Merck Manual

Please confirm that you are a health care professional

Loading

Childhood Vaccination Schedule

By

Michael J. Smith

, MD, MSCE, Duke University

Last full review/revision Dec 2019| Content last modified Dec 2019
Click here for Patient Education
NOTE: This is the Professional Version. CONSUMERS: Click here for the Consumer Version
Topic Resources

Vaccination follows a schedule recommended by the Centers for Disease Control and Prevention (CDC), the American Academy of Pediatrics, the American Academy of Family Physicians, and the American College of Obstetricians and Gynecologists. See tables Recommended Immunization Schedule for Ages 0–6 Years, Recommended Immunization Schedule for Ages 7–18 Years, and Catch-up Immunization Schedule for Ages 4 Months–18 Years.

Practitioners should also check for the CDC's latest recommendations (also available as a free mobile app), consult the CDC's child–adolescent immunization schedules and catch-up immunization schedule, and consult the relevant Advisory Committee on Immunization Practices (ACIP) statements for detailed recommendations and updates. Vaccination status should be reassessed at every visit.

For adverse effects and details of administration of specific vaccines, see Overview of Immunization.

Table
icon

Recommended Immunization Schedule for Ages 0–6 Years

Vaccine

Birth

1 month

2 months

4 months

6 months

9 months

12 months

15 months

18 months

19–23 months

2–3 years

4–6 years

Hepatitis B (HepB)[a]

1st dose

2nd dose

See footnote *

3rd dose

See footnote *

Rotavirus (RV)[b]

1st dose

2nd dose

See footnote [b]

1st dose

2nd dose

3rd dose

See footnote *

4th dose

See footnote *

5th dose

1st dose

2nd dose

See footnote [d]

See footnote *

3rd or 4th dose[d]

See footnote *

See footnote †

1st dose

2nd dose

3rd dose

See footnote *

4th dose

See footnote *

See footnote †

1st dose

2nd dose

3rd dose

See footnote *

4th dose

Influenza (inactivated influenza vaccine [IIV])[g]

Yearly, 1 or 2 doses

Influenza (live-attenuated influenza vaccine [LAIV])[g]

Yearly, 1 or 2 doses

NOTE: LAIV was not recommended for the 2017-2018 flu season; LAIV may be used during the 2019-2020 flu season.

See footnote [h]

1st dose

See footnote *

2nd dose

Varicella (VAR)[i]

1st dose

See footnote *

2nd dose

Hepatitis A (HepA)[j]

See footnote †

2-dose series[j]

See footnote ‡

Meningococcal vaccine (MenACWY-D for ages ≥ 9 months; MenACWY-CRM for ages ≥ 2 months)[k]

See footnotes † and [k]

See footnotes † and [e]

* = Range of recommended ages for catch-up immunization.

= Range of recommended ages for certain high-risk groups.

‡ = Range of recommended ages for catch-up and for certain high-risk groups.

This schedule includes recommendations from the CDC and the ACIP in effect as of February 5, 2019. Any dose not administered at the recommended age should be administered at a subsequent visit, when indicated and feasible. A combination vaccine should be used instead of separate injections when appropriate. Considerations should include provider assessment, patient preference, and the potential for adverse events. Vaccination providers should consult the relevant ACIP statement for detailed recommendations. Clinically significant adverse events that follow immunization should be reported to the Vaccine Adverse Event Reporting System (VAERS) using this site or by calling 800-822-7967. Suspected cases of vaccine-preventable diseases should be reported to the state or local health department. If children fall behind or start late, a catch-up schedule should be followed (see table Catch-up Immunization Schedule for Ages 4 Months–18 Years). For information about contraindications and precautions, see the ACIP's Vaccine Recommendations and Guidelines: Contraindications and Precautions.

For calculating intervals between doses, 4 weeks = 28 days. Intervals of ≥ 4 months are determined by calendar months.

Vaccine doses given ≤ 4 days before the minimum age or interval are considered valid. Doses given ≥ 5 days earlier than the minimum interval or minimum age are not considered valid and should be repeated as age-appropriate. The repeated dose is given after the invalid dose separated by the recommended minimum interval. For further guidance, see Table 3-1: Recommended and minimum ages and intervals between vaccine doses.

Within a number range (eg, 12–18 months), the dash means "through."

For information about people with immunocompromising conditions, see the ACIP's Vaccine Recommendations and Guidelines: Altered Immunocompetence.

For information about travel vaccine requirements, see the CDC's web site Travelers' Health.

For information about vaccinating during an outbreak of a vaccine-preventable disease, contact the state or local health department.

[a] Hepatitis B (HepB) vaccine. Minimum age is at birth.

At birth:

  • If the mother is hepatitis B surface antigen (HBsAg)–negative, administer 1 dose within 24 hours of birth for medically stable infants ≥ 2000 g. For infants < 2000 g, administer 1 dose at age 1 months or before hospital discharge.

  • If the mother is HBsAg-positive, administer HepB and 0.5 mL of hepatitis B immune globulin (HBIG) at separate anatomic sites within 12 hours of birth, regardless of birth weight. These infants should be tested for HBsAg and antibody to HBsAg (anti-HBs) at age 9–12 months. If the HepB series is delayed, test 1–2 months after the final dose.

  • If the mother’s HBsAg status is unknown, administer HepB vaccine to all infants within 12 hours of birth, regardless of birth weight. If infants weigh < 2000 g, administer 0.5 mL of HBIG in addition to HepB vaccine within 12 hours of birth. Determine the mother’s HBsAg status as soon as possible, and, if she is HBsAg-positive, administer 0.5 mL of HBIG to infants ≥ 2000 g as soon as possible but no later than age 7 days.

After the birth dose:

  • Administer the 2nd dose at age 1–2 months and the 3rd dose at age 6–18 months. Monovalent HepB vaccine should be used for doses administered before age 6 weeks.

  • Administration of a total of 4 doses of HepB vaccine is permissible when a combination vaccine containing HepB is administered after the birth dose.

  • Infants who did not receive a birth dose should receive 3 doses of a HepB-containing vaccine on a schedule of 0 months, 1–2 months, and 6 months starting as soon as feasible (see table Catch-up Immunization Schedule for Ages 4 Months–18 Years).

  • The minimum interval between dose 1 and dose 2 is 4 weeks, and between dose 2 and dose 3, it is 8 weeks. The final (3rd or 4th) dose in the HepB vaccine series should be administered no earlier than at age 24 weeks and at least 16 weeks after the first dose.

[b] Rotavirus (RV) vaccines. Minimum age is 6 weeks for RV-1 (Rotarix®) and RV-5 (RotaTeq®).

  • If RV-1 is used, administer 2 doses: At ages 2 months and 4 months.

  • If RV-5 is used, administer 3 doses: At ages 2 months, 4 months, and 6 months.

  • If any dose in a series was RV-5 or is unknown, 3 doses should be administered.

  • The maximum age for the final dose is 8 months, 0 days.

  • Vaccination should not be initiated in infants aged 15 weeks, 0 days or older (see table Catch-up Immunization Schedule for Ages 4 Months–18 Years).

[c] Diphtheria and tetanus toxoids and acellular pertussis (DTaP) vaccine. Minimum age is 6 weeks, except for DTaP-IPV vaccines (Kinrix® and Quadracel®), which have a minimum age of 4 years.

  • Administer a 5-dose DTaP series at ages 2, 4, 6, 15–18 months, and 4–6 years.

  • The 4th dose may be administered as early as age 12 months, provided at least 6 months have elapsed since the 3rd dose.

  • A 4th dose that was inadvertently given as early as age 12 months may be counted if it was given ≥ 4 months after the 3rd dose.

  • A 5th dose of DTaP vaccine is not needed if the 4th dose was administered at age ≥ 4 years.

[d] Haemophilus influenzae type b (Hib) vaccine. Minimum age is 6 weeks.

  • If PRP-T (ActHIB® or Hiberix®) or DTaP-IPV/Hib (Pentacel®) is used, administer 4 doses at ages 2, 4, 6, and 12–15 months.

  • If PRP-OMP (PedvaxHIB®) is used, administer 3 doses at ages 2, 4, and 12–15 months.

  • Administer only 1 dose to unvaccinated children aged 15–59 months.

Catch-up vaccination:

  • First dose given at age 7–11 months: Administer the 2nd dose at least 4 weeks later and the 3rd (final) dose at age 12–15 months or 8 weeks after 2nd dose (whichever is later).

  • First dose given at age 12–14 months: Administer the 2nd (final) dose at least 8 weeks after the first dose.

  • First dose given before age 12 months and 2nd dose before age 15 months: Administer the 3rd (final) dose 8 weeks after the 2nd dose.

  • 2 doses of PRP-OMP given before age 12 months: Administer the 3rd (final) dose at age 12–59 months and at least 8 weeks after the 2nd dose.

  • Unvaccinated at age 15–59 months: Administer only 1 dose.

  • For other catch-up recommendations, see table Catch-up Immunization Schedule for Ages 4 Months–18 Years.

Conditions that increase risk of Hib infection: The following are recommendations for children at increased risk of Hib infection. (Unimmunized means that the complete routine series was not given if children are aged < 14 months or that no doses were given if children are aged ≥ 14 months.)

  • Treatment with chemotherapy or radiation therapy: If children aged 12–59 months are unvaccinated or have been given only 1 dose before age 12 months, administer 2 doses separated by 8 weeks. If they have been given ≥ 2 doses before age 12 months, administer 1 dose at least 8 weeks after the previous dose. Doses given within 14 days of starting therapy or during therapy should be repeated at least 3 months after therapy is completed.

  • Receipt of a hematopoietic stem cell transplant: Administer the 3-dose series with doses 4 weeks apart, regardless of Hib vaccination history. The series should be started 6–12 months after successful transplantation.

  • Anatomic or functional asplenia, including sickle cell disease: If children aged 12–59 months are unvaccinated or have been given only 1 dose before age 12 months, administer 2 doses separated by 8 weeks. If they have been given ≥ 2 doses before age 12 months, administer 1 dose at least 8 weeks after the previous dose. Unimmunized children aged ≥ 5 years are given 1 dose.

  • Elective splenectomy: Administer 1 dose to unimmunized children aged ≥ 15 months; if possible, the vaccine should be given at least 14 days before procedure.

  • HIV infection: If children aged 12–59 months are unvaccinated or have been given only 1 dose before age 12 months, administer 2 doses separated by 8 weeks. If they have been given ≥ 2 doses before age 12 months, administer 1 dose at least 8 weeks after the previous dose. Unimmunized children aged 5–18 years are given 1 dose.

  • Immunoglobulin deficiency, early component complement deficiency: If children aged 12–59 months are unvaccinated or have been given only 1 dose before age 12 months, administer 2 doses separated by 8 weeks. If they have been given ≥ 2 doses before age 12 months, administer 1 dose at least 8 weeks after the previous dose.

[e] Pneumococcal vaccines. Minimum age is 6 weeks for 13-valent pneumococcal conjugate vaccine (PCV13) and 2 years for 23-valent pneumococcal polysaccharide vaccine (PPSV23).

  • Administer 4 doses of PCV13 at ages 2, 4, 6, and 12–15 months.

Catch-up vaccination:

Conditions that increase risk of pneumococcal infection: The following are recommendations for children who are aged 2–5 years and who have conditions that put them at risk. These conditions include chronic heart and lung disorders, diabetes mellitus, a cerebrospinal leak, a cochlear implant, and certain immunocompromising conditions (eg, sickle cell disease, asplenia, HIV infection, chronic kidney failure, nephrotic syndrome, certain cancers, treatment with immunosuppressants, solid organ transplantation, multiple myeloma). For further guidance, see the ACIP's recommendations for use of the pneumococcal vaccine in children. For recommendations for children aged 7–18 years, see table Recommended Immunization Schedule for Children and Adolescents Ages 7–18 Years).

  • If possible, administer PCV13 doses before PPSV23.

  • If children have been given only 3 doses, administer 1 PCV13 dose at least 8 weeks after the previous PCV13 dose. If they have been given < 3 doses, administer 2 doses: at 8 weeks and at 16 weeks after the previous dose.

  • If children have not been given PPSV23, administer 1 dose of PPSV23 at least 8 weeks after any previous PCV13 dose. Children who have an immunocompromising condition (see above) are given a 2nd dose 5 years after the first.

[f] Inactivated poliovirus vaccine (IPV). Minimum age is 6 weeks.

  • Administer a 4-dose IPV series at ages 2, 4, 6–18 months, and 4–6 years. The final dose in the series should be administered on or after the 4th birthday and at least 6 months after the previous dose.

  • When a combination vaccine containing IPV is used, ≥ 4 doses can be administered before the 4th birthday, but a dose is still recommended after the 4th birthday and at least 6 months after the previous dose.

  • During the first 6 months of life, minimum age and minimum intervals are recommended only if the infant is at risk of imminent exposure to circulating poliovirus (eg, traveling to a polio-endemic region, during an outbreak).

Catch-up vaccination:

  • If ≥ 4 doses are administered before age 4 years, an additional dose should be administered at age 4–6 years and at least 6 months after the previous dose.

  • A 4th dose is not necessary if the 3rd dose was administered at age ≥ 4 years and at least 6 months after the previous dose.

  • For other catch-up recommendations, see Table: Catch-up Immunization Schedule for Ages 4 Months–18 Years.

For series that contain oral polio vaccine (OPV), either only OPV or mixed OPV-IPV:

  • The total number of doses needed to complete the series is the same as that recommended for the US IPV schedule.

  • Only trivalent OPV (tOPV) fulfills US vaccination requirements. For further guidance on assessing doses documented as OPV, see the CDC's guidance for assessment of poliovirus vaccination status.

[g] Influenza vaccine (seasonal). Minimum age is 6 months for inactivated influenza vaccine (IIV) and 2 years for live-attenuated influenza vaccine (LAIV). NOTE: Live-attenuated influenza vaccine (LAIV) was not recommended for the 2017–2018 flu season; LAIV may be used during the 2019–2020 flu season.

  • For most healthy children aged ≥ 2 years, either LAIV or IIV may be used. However, LAIV should not be administered to some children, including children with asthma, children aged 2–4 years who have asthma or have had wheezing in the past 12 months, and children who have any other medical conditions that predispose them to influenza complications. For all other contraindications to the use of LAIV, see the ACIP's 2019–2020 recommendations .

  • Administer annually an age formulation and dose of influenza vaccine that is appropriate for patient's age and health status.

  • Children aged 6 months–8 years who did not receive ≥ 2 doses of influenza vaccine before July 1, 2019, should be given 2 doses separated by at least 4 weeks.

  • For further guidance, see the ACIP's 2019–2020 recommendations.

[h] Measles, mumps, and rubella (MMR) vaccine. Minimum age is 12 months for routine vaccination.

  • Administer 2 doses at ages 12–15 months and 4–6 years. The 2nd dose may be given as early as 4 weeks after the first dose.

  • Catch-up vaccination: For unvaccinated children, administer 2 doses at least 4 weeks apart.

  • International travel: Administer 1 dose of MMR vaccine to infants aged 6–11 months who are traveling internationally. Revaccinate these children with 2 doses of MMR vaccine: the first dose at age 12–15 months (at age 12 months if the child remains in a high-risk area) and the 2nd dose given at least 4 weeks after the previous dose. For unvaccinated children aged ≥ 12 months, administer 2 doses at least 4 weeks apart before departure.

[i] Varicella (VAR) vaccine. Minimum age is 12 months.

  • Administer 2 doses at ages 12–15 months and 4–6 years.

  • The 2nd dose may be given as early as 3 months after the first dose; a dose given after a 4-week interval may be counted.

[j] Hepatitis A (HepA) vaccine. Minimum age is 12 months.

  • Administer 2 doses, separated by 6–18 months, between the first and 2nd birthdays. A series begun before the 2nd birthday should be completed even if the child turns 2 before the 2nd dose is given.

Catch-up vaccination:

  • Anyone aged ≥ 2 years may be given the HepA vaccine if desired. Minimum interval between doses is 6 months.

International travel:

  • Administer 1 dose of HepA vaccine to infants aged 6–11 months who are traveling internationally. Then administer 2 doses, separated by 6–18 months, between 12 to 23 months of age.

Increased risk of hepatitis A: Unvaccinated children are vaccinated if they are at increased risk of hepatitis A. Risk factors include

  • Travel to endemic areas

  • A clotting factor disorder

  • Treatment with clotting factor concentrates

  • A chronic liver disorder

  • Homelessness

  • Anticipated close personal contact (eg, as members of the household) with an adopted child during the first 60 days after the child's arrival in the US from an endemic area

[k] Serogroup A, C, W, Y meningococcal vaccines. Minimum age is 2 months for MenACWY-CRM (Menveo®) and 9 months for MenACWY-D (Menactra®). Routine vaccination is a 2-dose series, given at ages 11–12 years and 16 years, but the vaccine is given to younger children who are at increased risk.

For children who have persistent complement component deficiency (including those taking eculizumab) or anatomic or functional asplenia, sickle cell disease, or HIV infection: One of the following can be used:

  • MenACWY-CRM: Administer a 4-dose series at ages 2, 4, 6, and 12 months. If the first dose is given at age 7–23 months, administer 2 doses, with the 2nd dose given at least 12 weeks after the first dose and after the first birthday. If the first dose is given at age ≥ 24 months, administer 2 doses separated by at least 8 weeks.

  • MenACWY-D: Administer 2 doses at least 12 weeks apart if children are aged 9–23 months and at least 8 weeks apart if they are aged ≥ 24 months. If children aged ≥ 24 months have asplenia, sickle cell disease, or HIV infection, administer 2 doses at least 8 weeks apart. MenACWY-D must be given at least 4 weeks after the PCV13 series is completed.

For children who live in or are traveling to countries where meningococcal disease is hyperendemic or epidemic:

  • MenACWY-CRM: Administer 4 doses at ages 2, 4, 6, and 12 months. If the first dose is given at age 7–23 months, administer 2 doses, with the 2nd dose given at least 12 weeks after the first dose and after the first birthday.

  • MenACWY-D: For children aged 9–23 months, administer 2 doses at least 12 weeks apart; the 2nd dose may be given as early as 8 weeks after the first dose to children who are traveling.

  • For children age ≥ 2 years, administer 1 dose of MenACWY-CRM or MenACWY-D.

The CDC also recommends vaccinating people identified as being at increased risk during a meningococcal disease outbreak.

For further guidance, see the ACIP's meningococcal vaccine recommendations, particularly the ACIP's recommendations for the use of MenACWY-CRM in children.

ACIP = Advisory Committee on Immunization Practices; CDC = Centers for Disease Control and Prevention; PRP-OMP = Neisseria meningitidis polyribosyl ribitol phosphate/outer membrane protein.

Adapted from the CDC: Recommended Child and Adolescent Immunization Schedule for ages 18 years or younger, United States, 2019. Available here.

Table
icon

Recommended Immunization Schedule for Ages 7–18 Years

Vaccine

7–10 years

11–12 years

13–15 years

16 years

17–18 years

Hepatitis B (HepB)[a]

See footnote *

See footnotes † and [b]

See footnotes † and [c]

See footnotes * and [d]

Influenza inactivated influenza vaccine [IIV][e]

Yearly, 1 or 2 doses (age 6 months–8 years)

Yearly, 1 dose

Live-attenuated influenza vaccine [LAIV][e]

Yearly, 1 or 2 doses (age 2–8 years)

Yearly, 1 dose

NOTE: LAIV was not recommended for the 2017–2018 flu season; LAIV may be used during the 2019–2020 flu season.

See footnotes * and [f]

Varicella (VAR)[g]

See footnote *

Hepatitis A (HepA)[h]

See footnote ‡

Meningococcal vaccines, quadrivalent (MenACWY-D and MenACWY-CRM)[i]

See footnote †

First dose

See footnote †

2nd dose

See footnote †

See footnote *

Tdap

See footnote ‡

See footnotes † and §

See footnote [k]

See footnote *

See footnotes † and [l]

See footnote §

* = Range of recommended ages for catch-up immunization.

= Range of recommended ages for certain high-risk groups.

‡ = Range of recommended ages for catch-up and for certain high-risk groups.

§ = Range of recommended ages for groups that are not high-risk but may be given the vaccine based on clinical judgment.

This schedule includes recommendations from the CDC and the ACIP in effect as of February 5, 2019. Any dose not administered at the recommended age should be administered at a subsequent visit, when indicated and feasible. A combination vaccine should be used instead of separate injections when appropriate.

Vaccination providers should consult the relevant ACIP statement for detailed recommendations.

Clinically significant adverse events that follow immunization should be reported to the Vaccine Adverse Event Reporting System (VAERS) using this site or by calling 800-822-7967. Suspected cases of vaccine-preventable diseases should be reported to the state or local health department. If children fall behind or start late, a catch-up schedule should be followed (see table Catch-up Immunization Schedule for Ages 4 Months–18 Years). For information about contraindications and precautions, see the ACIP's Vaccine Recommendations and Guidelines: Contraindications and Precautions.

For calculating intervals between doses, 4 weeks = 28 days. Intervals of ≥ 4 months are determined by calendar months.

Vaccine doses administered ≤ 4 days before the minimum age or interval are considered valid. Doses administered ≥ 5 days earlier than the minimum interval or minimum age are not considered valid and should be repeated as age-appropriate. The repeated dose is given after the invalid dose separated by the recommended minimum interval. For further guidance, see Table 3-1: Recommended and minimum ages and intervals between vaccine doses.

For information about people with immunocompromising conditions, see the ACIP's Vaccine Recommendations and Guidelines: Altered Immunocompetence.

For information about travel vaccine requirements, see the CDC's web site Travelers' Health.

For information about vaccinating during an outbreak of a vaccine-preventable disease, contact the state or local health department.

[a] Hepatitis B (HepB) vaccine.

  • Administer the 3-dose series at 0, 1–2, and 6 months to children not previously vaccinated.

  • For children with incomplete vaccination, follow the catch-up recommendations (see table Catch-up Immunization Schedule for Ages 4 Months–18 Years).

  • A 2-dose series (doses separated by at least 4 months) of adult formulation Recombivax HB® may be used in adolescents aged 11–15 years.

[b] Haemophilus influenzae type b (Hib) conjugate vaccine.

  • Hib vaccine is not routinely given to patients > 5 years. However, it is given to younger children who are at increased risk.

  • Administer 1 dose to unimmunized patients aged ≥ 5 years if they have anatomic or functional asplenia (including sickle cell disease).

  • Administer 1 dose to unimmunized patients aged 5–18 years if they have HIV infection.

  • Administer a single dose of any vaccine that contains Hib to unimmunized children and adolescents aged ≥ 15 months if they are having an elective splenectomy; if possible, the vaccine should be given at least 14 days before procedure.

  • For patients aged ≥ 14 months, unimmunized means that they have received no doses of Hib vaccine.

[c] Pneumococcal vaccines (13-valent pneumococcal conjugate vaccine [PCV13] and 23-valent pneumococcal polysaccharide vaccine [PPSV23]).

Conditions that increase risk of pneumococcal infection: The following are recommendations for children who are aged 6–18 years and who have conditions that increase the risk of pneumococcal disease.

  • Administer PCV13 doses before PPSV23 if possible.

Chronic heart or lung disorders or diabetes mellitus:

  • If no doses of PPSV23 have been given, administer 1 dose of PPSV23 at least 8 weeks after any previous PCV13 dose.

Cerebrospinal leak or a cochlear implant:

  • If no doses of PCV13 or PPSV23 have been given, administer 1 dose of PCV13 followed by 1 dose of PPSV23 at least 8 weeks later.

  • If any doses of PCV13 have been given but no PPSV23, administer 1 dose of PPSV23 at least 8 weeks after the previous dose of PCV13.

  • If PPSV23 has been given but no PCV13, administer 1 dose of PCV13 at least 8 weeks after the previous dose of PPSV23.

Certain immunocompromising conditions (eg, sickle cell disease, other hemoglobinopathies, immunodeficiency, asplenia, HIV infection, chronic kidney failure, nephrotic syndrome, certain cancers, treatment with immunosuppressants, solid organ transplantation, multiple myeloma):

  • If no doses of PCV13 or PPSV23 have been given, administer 1 dose of PCV13 followed by 2 doses of PPSV23; the first PPSV23 dose is given 8 weeks after the PCV13 dose, and the 2nd dose is given at least 5 years after the first PPSV23 dose.

  • If any doses of PCV13 have been given but no PPSV23, administer 2 doses of PPSV23; the first PPSV23 dose is given 8 weeks after the previous PCV13 dose, and the 2nd dose is given at least 5 years after the first PPSV23 dose.

  • If PPSV23 has been given but no PCV13, administer 1 dose of PCV13 at least 8 weeks after the previous dose of PPSV23 and a 2nd dose of PPSV23 5 years after the first PPSV23 dose and at least 8 weeks after the PCV13 dose.

Chronic liver disease or alcoholism:

  • If no doses of PPSV23 have been given, administer 1 dose of PPSV23 at least 8 weeks after any previous PCV13 dose.

If the PCV13 series is incomplete, the number and timing of additional PCV13 doses are determined by the age when first dose was given. For further guidance, see the ACIP's recommendations for use of the pneumococcal vaccine in children.

[d] Inactivated poliovirus vaccine (IPV).

For series that contain oral polio vaccine (OPV), either only OPV or mixed OPV-IPV:

  • The total number of doses needed to complete the series is the same as that recommended for the US IPV schedule.

  • Only trivalent OPV (tOPV) fulfills US vaccination requirements. For further guidance on assessing doses documented as OPV, see the CDC's guidance for assessment of poliovirus vaccination status.

[e] Influenza vaccines (inactivated influenza vaccine [IIV] and live-attenuated influenza vaccine [LAIV]).

  • If children aged 6 months–8 years were not given ≥ 2 doses of influenza vaccine before July 1, 2019, administer 2 doses separated by at least 4 weeks.

  • Administer 1 dose of influenza vaccine to people aged ≥ 9 years.

  • The live-attenuated influenza vaccine (LAIV) was not recommended for the 2017–2018 season. It may be used during the 2019–2020 season.

  • For further guidance, see the ACIP's 2019–2020 recommendations.

[f] Measles, mumps, and rubella (MMR) vaccine.

  • Catch-up vaccination: For unvaccinated children and adolescents, administer 2 doses at least 4 weeks apart.

[g] Varicella (VAR) vaccine.

  • If people aged 7–18 years do not have evidence of immunity, administer 2 doses of varicella vaccine with the 2nd dose given 3 months after the first dose for children aged 7–12 years and given at least 4 weeks after the first dose for adolescents ≥ 13 years. Minimum interval for both age groups is 4 weeks.

  • For further guidance, see the ACIP's recommendations for prevention of varicella.

[h] Hepatitis A (HepA) vaccine.

Catch-up vaccination:

  • Anyone aged ≥ 2 years may be given the HepA vaccine if desired; 2 doses are given. Minimum interval between doses is 6 months.

Increased risk of hepatitis A: Unvaccinated children are vaccinated if they are at increased risk of hepatitis A. Risk factors include

  • Travel to or work in endemic areas

  • Men who have sex with men

  • Use of illicit drugs (injected or not)

  • A clotting factor disorder

  • Treatment with clotting factor concentrates

  • A chronic liver disorder

  • Homelessness

  • Anticipated close personal contact (eg, as members of the household or as regular babysitters) with an adopted child during the first 60 days after the child's arrival in the US from an endemic area

[i] Serogroup A, C, W, Y meningococcal vaccines (MenACWY-CRM [Menveo®] and MenACWY-D [Menactra®]):

  • Administer a 2-dose series at age 11–12 years and at age 16 years.

  • If the first dose is administered at age 13–15 years, a booster dose should be administered at age 16–18 years with a minimum interval of at least 8 weeks after the preceding dose.

  • If the first dose is administered at age 16–18 years, a booster dose is not needed.

Catch-up recommendations for children who have persistent complement component deficiency (including those taking eculizumab), anatomic or functional asplenia, sickle cell disease, or HIV infection: One of the following can be used:

  • MenACWY-CRM: If the first dose is given at age ≥ 24 months, administer 2 doses separated by at least 8 weeks.

  • MenACWY-D: Administer 2 doses at least 8 weeks apart if children are aged ≥ 24 months. MenACWY-D must be given at least 4 weeks after the PCV13 series is completed.

Catch-up recommendations for children who live in or are traveling to countries where meningococcal disease is hyperendemic or epidemic:

  • For children age ≥ 2 years, administer 1 dose of MenACWY-CRM or MenACWY-D.

The CDC recommends vaccinating people identified as being at increased risk during a meningococcal disease outbreak. Which vaccine they should receive depends on the serogroup causing the outbreak.

For further guidance (including use in patients at increased risk), see the ACIP's meningococcal vaccine recommendations and the CDC's The Pink Book: Meningococcal Disease.

[j] Tetanus and diphtheria toxoids and acellular pertussis (Tdap) vaccine. Minimum age is 11 years for routine vaccination and 7 years for catch-up vaccination.

  • Administer 1 dose to adolescents aged 11–12 years.

  • For pregnant adolescents, administer 1 dose during each pregnancy, preferably at 27–36 weeks gestation. Tdap may be administered regardless of the interval since receipt of the last tetanus- and diphtheria-toxoid–containing vaccine.

  • If adolescents aged 13–18 years have not received Tdap vaccine, administer 1 dose of Tdap followed by tetanus and diphtheria toxoids (Td) booster doses every 10 years thereafter.

  • For children and adolescents aged 7–18 years who are not fully immunized with the childhood diphtheria-tetanus-acellular pertussis (DTaP) vaccine series, administer 1 dose of Tdap vaccine as part of the catch-up series, preferably the first dose. If additional doses are needed, use Td vaccine.

  • Children who were given Tdap inadvertently at age 7–10 years or as part of a catch-up series should be given the routine Tdap dose at age 11–12 years.

  • An inadvertent dose of DTaP vaccine administered to children aged 7–10 years can be counted as part of the catch-up series. The routine dose of Tdap should be given at age 11–12 years. If adolescents aged 11–18 years are inadvertently given DTaP, it can be counted as the adolescent Tdap dose.

[k] Human papillomavirus (HPV) vaccine. Minimum age is 9 years.

  • Routine vaccination with HPV is recommended at age 11 or 12 years (can start at age 9 years) and for previously unvaccinated or not adequately vaccinated patients up through age 26 years.

The number of doses (2 or 3 doses) depends on age at the first dose:

  • Age 9–14 years: Administer a 2-dose series at 0 and 6–12 months. Minimum interval is 5 months. Repeat if a dose is given too soon; repeat the dose at least 12 weeks after the invalid dose and at least 5 months after the first dose.

  • Age ≥ 15 years: Administer a 3-dose series at 0, 1–2 months, and 6 months. Minimum intervals are 4 weeks between the first and 2nd dose, 12 weeks between the 2nd and 3rd dose, and 5 months between the first and 3rd dose. If any dose is given too soon, repeat the dose at or after the minimum interval since the previous dose.

  • People who have completed a valid series with any HPV vaccine do not need additional doses.

Special situations:

  • History of sexual abuse or assault: Begin the series at age 9 years.

  • Immunocompromising conditions (including HIV infection): Administer a 3-dose series at 0 months, 1–2 months, and 6 months to patients aged 9–26 years.

  • Pregnancy: Vaccination during pregnancy is not recommended, but there is no evidence that the vaccine is harmful. No intervention is needed for women who are inadvertently given a dose of HPV vaccine while they are pregnant. Delay remaining doses until after pregnancy. Pregnancy testing is not needed before vaccination.

  • For further guidance, see the ACIP's updated recommendations for the HPV vaccine.

[l] Serogroup B meningococcal vaccines (MenB [Bexsero®, Trumenba®]). Minimum age is 10 years.

  • MenB vaccines may be given at clinical discretion to any adolescents aged 16–23 years (preferably at age 16–18 years) who want it, even if they are not at increased risk.

  • Administer 2 doses of Bexsero® at least 1 month apart.

  • Administer 2 doses of Trumenba® at least 6 months apart. If the 2nd dose is given earlier than 6 months, give a 3rd dose at least 4 months after the 2nd dose.

  • Bexsero® and Trumenba® are not interchangeable.

  • For further guidance, see the ACIP's meningococcal vaccine recommendations.

Conditions that increase risk of meningococcal B infection: The following are recommendations for children and adolescents who have conditions that put them at risk. These conditions include having anatomic or functional asplenia, sickle cell disease, and persistent complement component deficiency (including use of eculizumab):

  • Administer 2 doses of Bexsero® at least 1 month apart.

  • Administer 3 doses of Trumenba® at 0 months, 1–2 months, and 6 months.

ACIP = Advisory Committee on Immunization Practices; CDC = Centers for Disease Control and Prevention.

Adapted from the CDC: Recommended Child and Adolescent Immunization Schedule for ages 18 years or younger, United States, 2019. Available here.

Table
icon

Catch-up Immunization Schedule for Ages 4 Months–18 Years

Vaccine

Minimum Age for Dose 1

Minimum Interval Between Doses 1 and 2

Minimum Interval Between Doses 2 and 3

Minimum Interval Between Doses 3 and 4

Minimum Interval Between Doses 4 and 5

For ages 4 months–6 years

Hepatitis B (HepB)[a]

Birth

4 weeks

8 weeks and at least 16 weeks after the first dose

Minimum age for the final dose: 24 weeks

Rotavirus (RV)[b]

6 weeks

Maximum age for the first dose: 14 weeks, 6 days

4 weeks

4 weeks[b]

6 weeks

4 weeks

4 weeks

6 months

6 months[c]

6 weeks

4 weeks if the first dose was administered at age < 12 months

8 weeks (as the final dose) if the first dose was administered at age 12–14 months

No further doses needed if the first dose was administered at age 15 months

4 weeks[d] if the current age is < 12 months and the first dose was administered at age < 7 months and ≥ 1 previous dose was PRP-T (ActHib®, Pentacel®, Hiberix®) or unknown

8 weeks and age 12–59 months (as the final dose)[d] if one of the following is present:

  • The current age is < 12 months and the first dose was administered at age 7–11 months.

or

  • The current age is 12–59 months and the first dose was administered at age <12 months and the 2nd dose was administered at age < 15 months.

or

  • The first 2 doses were PRP-OMP (PedvaxHIB®, Comvax®) and administered at age < 12 months.

No further doses needed if the previous dose is administered at age 15 months

8 weeks (as the final dose)

Only necessary for children aged 12–59 months who received 3 dose before age 12 months

6 weeks

4 weeks if the first dose was administered at age < 12 months.

8 weeks (as the final dose for healthy children) if the first dose was administered at age 12–14 months

No further doses needed for healthy children if the first dose is administered at age 24 months

4 weeks if the current age is < 12 months and the previous dose was given at age < 7 months

8 weeks (as the final dose for healthy children) if one of the following is present:

  • The previous dose was given at age 7–11 months and the current age is 12 months.

or

  • The current age is ≥12 months and at least 1 dose was given before age 12 months.

No further doses needed for healthy children if the previous dose is administered at age 24 months

8 weeks (as the final dose)

Only necessary for children aged 12–59 months who received 3 doses before age 12 months or for high-risk children who received 3 doses at any age

6 weeks

4 weeks[f]

4 weeks[f] if the current age is < 4 years

6 months as the final dose if the current age is ≥ 4 years

6 months[f]

Minimum age: 4 years for the final dose

Meningococcal ACWY[g]

6 weeks

8 weeks[g]

See footnote [g]

See footnote [g]

12 months

4 weeks

Varicella (VAR)[i]

12 months

3 months

Hepatitis A (HepA)[j]

12 months

6 months

For ages 7–18 years

Tetanus, diphtheria, acellular pertussis (Tdap)[k]

7 years[k]

4 weeks

4 weeks if the first dose of DTaP/DT was administered at age < 12 months

6 months (as the final dose) if the first dose of DTaP/DT or Tdap/Td was administered at age 12 months

6 months if the first dose of DTaP/DT was administered at age < 12 months

9 years

Routine dosing intervals recommended[l]

Hepatitis A (HepA)[j]

N/A

6 months

Hepatitis B (HepB)[a]

N/A

4 weeks

8 weeks and at least 16 weeks after the first dose

Inactivated polio virus (IPV)[f]

N/A

4 weeks

6 months[f]

A 4th dose not necessary if the 3rd dose was administered at age ≥ 4 years and at least 6 months after the previous dose

A 4th dose of IPV required if all previous doses were administered at age < 4 years or if the 3rd dose was administered < 6 months after the 2nd dose

Meningococcal ACWY conjugate[g]

N/A

8 weeks[g]

Measles, mumps, rubella (MMR)[h]

N/A

4 weeks

Varicella (VAR)[i]

N/A

3 months if age is < 13 years

4 weeks if age is 13 years

NOTE: For children whose vaccinations were started late or are > 1 month behind, this table provides catch-up schedules and minimum intervals between doses (see also the CDC's recommended catch-up immunization schedule). A vaccine series does not need to be restarted, regardless of the time that has elapsed between doses. Use the section appropriate for the child’s age.

Always use this table in conjunction with the CDC's child and adolescent immunization schedules, including their footnotes (see also table Recommended Immunization Schedule for Ages 0–6 Years and table Recommended Immunization Schedule for Ages 7–18 Years).

Clinically significant adverse events that follow immunization should be reported to the Vaccine Adverse Event Reporting System (VAERS) using this site or by calling 800-822-7967. Suspected cases of vaccine-preventable diseases should be reported. For information about contraindications and precautions, see the ACIP's Vaccine Recommendations and Guidelines: Contraindications and Precautions.

For calculating intervals between doses, 4 weeks = 28 days. Intervals of ≥ 4 months are determined by calendar months.

Vaccine doses administered ≤ 4 days before the minimum age or interval are considered valid. Doses administered ≥ 5 days earlier than the minimum interval or minimum age are not considered valid and should be repeated as age-appropriate. The repeated dose is given after the invalid dose separated by the recommended minimum interval. For further guidance, see Table 3-1: Recommended and minimum ages and intervals between vaccine doses.

For information about travel vaccine requirements, see the CDC's web site Travelers' Health.

For information about vaccinating during an outbreak of a vaccine-preventable disease, contact the state or local health department.

[a] Hepatitis B (HepB) vaccine.

  • Administer the 3-dose series to children not previously vaccinated.

  • A 2-dose series (with doses separated by at least 4 months) of adult formulation Recombivax HB® can be used in adolescents aged 11–15 years.

[b] Rotavirus (RV) vaccines.

  • Vaccination should not be initiated in infants aged 15 weeks 0 days. The maximum age is 8 months 0 days for the final dose in the series.

[c] Diphtheria and tetanus toxoids and acellular pertussis (DTaP) vaccine.

  • The 5th dose is not necessary if the 4th dose was administered at age 4 years.

[d] Haemophilus influenzae type b (Hib) conjugate vaccine.

  • First dose given at age 7–11 months: Administer the 2nd dose at least 4 weeks later and the 3rd (final) dose at 12–15 months or 8 weeks after the 2nd dose (whichever is later).

  • First dose given at age 12–14 months: Administer the 2nd (final) dose at least 8 weeks after the first dose.

  • First dose given before age 12 months and the 2nd dose given before 15 months: Administer the 3rd (final) dose 8 weeks after the 2nd dose.

  • 2 doses of PRP-OMP (PedvaxHIB®, Comvax®) given before 12 months: Administer the 3rd (final) dose at age 12–59 months and at least 8 weeks after the 2nd dose.

  • Unvaccinated at age 15–59 months: Administer only 1 dose.

Conditions that increase risk of Hib infection: The following are recommendations for children at increased risk of Hib infection. (Unimmunized means that the complete routine series was not given if children are aged up to 14 months or that no doses were given if children are aged ≥ 14 months.)

  • Treatment with chemotherapy or radiation therapy: If children aged 12–59 months are unvaccinated or have been given only 1 dose before age 12 months, administer 2 doses separated by 8 weeks. Doses given within 14 days of starting therapy or during therapy should be repeated at least 3 months after therapy is completed.

  • Receipt of a hematopoietic stem cell transplant: Administer the 3-dose series with doses 4 weeks apart, regardless of Hib vaccination history. The series should be started 6–12 months after successful transplantation.

  • Anatomic or functional asplenia, including sickle cell disease: If children aged 12–59 months are unvaccinated or have been given only 1 dose before age 12 months, administer 2 doses separated by 8 weeks. If they have been given ≥ 2 doses before age 12 months, administer 1 dose at least 8 weeks after the previous dose. Unimmunized children and adolescents ≥ 5 years are given 1 dose.

  • Elective splenectomy: Administer 1 dose to unimmunized children aged ≥ 15 months; if possible, the vaccine should be given at least 14 days before procedure.

  • HIV infection: If children aged 12–59 months are unvaccinated or have been given only 1 dose before age 12 months, administer 2 doses separated by 8 weeks. If they have been given ≥ 2 doses before age 12 months, administer 1 dose at least 8 weeks after the previous dose. Unimmunized children aged 5–18 years are given 1 dose.

  • Immunoglobulin deficiency, early component complement deficiency: If children aged 12–59 months are unvaccinated or have been given only 1 dose before age 12 months, administer 2 doses separated by 8 weeks. If they have been given ≥ 2 doses before age 12 months, administer 1 dose at least 8 weeks after the previous dose.

[e] Pneumococcal vaccines. Minimum age is 6 weeks for 13-valent pneumococcal conjugate vaccine (PCV13) and 2 years for 23-valent pneumococcal polysaccharide vaccine (PPSV23). For further guidance, see the ACIP's recommendations for use of the pneumococcal vaccine in children.

  • Catch-up vaccination with PCV13: 1 dose for healthy children aged 24–59 months if PCV13 doses have not been completed per the ACIP's recommended catch-up schedule.

Conditions that increase risk of pneumococcal infection: The following are catch-up recommendations for children have conditions that put them at risk. These conditions include chronic heart and lung disorders, diabetes mellitus, a cerebrospinal leak, a cochlear implant, certain immunocompromising conditions (eg, sickle cell disease, other hemoglobinopathies, asplenia, HIV infection, chronic kidney failure, nephrotic syndrome, certain cancers, treatment with immunosuppressants), solid organ transplantation, multiple myeloma, chronic liver disease, and alcoholism.

  • If possible, administer PCV13 doses before PPSV23.

For children aged 2–5 years with any condition that increases risk:

  • If 3 doses of PCV13 were administered previously, administer 1 dose of PCV13 at least 8 weeks after the previous dose.

  • If < 3 doses of PCV13 were administered previously, administer 2 doses of PCV13 8 weeks after the previous dose and 8 weeks apart.

  • If they have not been given PPSV23, administer 1 dose of PPSV23 at least 8 weeks after any previous dose of PCV13.

For children and adolescents aged 6–18 years with chronic heart or lung disorders or diabetes mellitus:

  • If no dose of PPSV23 have been given, administer 1 dose of PPSV23 at least 8 weeks after any previous PCV13 dose.

For children and adolescents aged 6–18 years with a cerebrospinal leak or a cochlear implant:

  • If no doses of PCV13 or PPSV23 have been given, administer 1 dose of PCV13 followed by 1 dose of PPSV23 at least 8 weeks later.

  • If any doses of PCV13 have been given but no PPSV23, administer 1 dose of PPSV23 at least 8 weeks after the previous dose of PCV13.

  • If any doses PPSV23 have been given but no PCV13, administer 1 dose of PCV13 at least 8 weeks after the previous dose of PPSV23.

For children and adolescents aged 6–18 years with certain immunocompromising conditions (eg, sickle cell disease, other hemoglobinopathies, asplenia, HIV infection, chronic kidney failure, nephrotic syndrome, certain cancers, treatment with immunosuppressants):

  • If no doses of PCV13 or PPSV23 have been given, administer 1 dose of PCV13 followed by 2 doses of PPSV23; the first PPSV23 dose is given 8 weeks after the PCV13 dose, and the 2nd dose is given at least 5 years after the first PPSV23 dose.

  • If any doses of PCV13 have been given but no PPSV23, administer 2 doses of PPSV23; the first PPSV23 dose is given 8 weeks after the previous PCV13 dose, and the 2nd dose is given at least 5 years after the first PPSV23 dose.

  • If any doses of PPSV23 have been given but no PCV13, administer 1 dose of PCV13 at least 8 weeks after the previous dose of PPSV23 and a 2nd dose of PPSV23 5 years after the first PPSV23 dose and at least 8 weeks after the PCV13 dose.

For children and adolescents aged 6–18 years with chronic liver disease or alcoholism:

  • If no doses of PPSV23, administer 1 dose of PPSV23 at least 8 weeks after any previous PCV13 dose.

If the PCV13 series is incomplete, the number and timing of additional PCV13 doses are determined by the age when first dose was given. For further guidance, see the ACIP's recommendations for use of the pneumococcal vaccine in children.

[f] Inactivated poliovirus vaccine (IPV).

  • During the first 6 months of life, minimum ages and minimum intervals are recommended only if the infant is at risk of imminent exposure to circulating poliovirus (eg, traveling to a polio-endemic region, during an outbreak).

  • If ≥ 4 doses were given before age 4 years, administer an additional dose at age 4–6 years and at least 6 months after the previous dose.

  • A 4th dose is not necessary if the 3rd dose was administered at age ≥ 4 years and at least 6 months after the previous dose.

  • IPV is not routinely recommended for US residents ≥ 18 years.

For series that contain oral polio vaccine (OPV), either only OPV or mixed OPV-IPV:

  • The total number of doses needed to complete the series is the same as that recommended for the US IPV schedule.

  • Only trivalent OPV (tOPV) fulfills US vaccination requirements. For further guidance on assessing doses documented as OPV, see the CDC's guidance for assessment of poliovirus vaccination status.

[g] Serogroup A, C, W, Y meningococcal vaccines (MenACWY-CRM [Menveo®] and MenACWY-D [Menactra®]).

[h] Measles, mumps, and rubella (MMR) vaccine.

  • For unvaccinated children and adolescents, administer 2 doses at least 4 weeks apart.

[i] Varicella (VAR) vaccine.

  • If people aged 7–18 years do not have evidence of immunity, administer 2 doses of varicella vaccine with the 2nd dose given 3 months after the first dose for children aged 7–12 years and at least 4 weeks after the first dose for adolescents ≥ aged 13 years. In children aged 7–12 years, the 2nd dose can be administered as early as 4 weeks after the first dose if needed.

  • For further guidance, see the ACIP's recommendations for prevention of varicella.

[j] Hepatitis A (HepA) vaccine.

Increased risk of hepatitis A: Unvaccinated children are vaccinated if they are at increased risk of hepatitis A. Risk factors include

  • Travel to or work in endemic areas

  • Men who have sex with men

  • Use of illicit drugs (injected or not)

  • A clotting factor disorder

  • Treatment with clotting factor concentrates

  • A chronic liver disorder

  • Homelessness

  • Anticipated close personal contact (eg, as members of the household or as regular babysitters) with an adopted child during the first 60 days after the child's arrival in the US from an endemic area

[k] Tetanus and diphtheria toxoids (Td) and tetanus and diphtheria toxoids and acellular pertussis (Tdap) vaccines.

  • If adolescents aged 13–18 years have not received Tdap, administer 1 dose, followed by a Td booster every 10 years.

  • If children and adolescents aged 7–18 years are not fully immunized with diphtheria-tetanus-acellular pertussis (DTaP), administer 1 dose of Tdap as part of the catch-up series, preferably the first. If additional doses are needed, use Td vaccine.

  • Children aged 7–10 years who were given Tdap inadvertently or as part of the catch-up series may be given the routine Tdap dose at 11–12 years.

  • An inadvertent dose of DTaP vaccine administered to children aged 7–10 years can be counted as part of the catch-up series. The routine dose of Tdap may be given at age 11–12 years.

  • An inadvertent dose of DTaP vaccine administered to adolescents aged 11–18 years can be counted as the adolescent Tdap dose.

[l] Human papillomavirus (HPV) vaccine.

  • Routine vaccination with HPV is recommended for all adolescents at age 11 or 12 years (can start at age 9) and for previously unvaccinated or not adequately vaccinated patients up through age 26 years.

The number of doses (2 or 3 doses) depends on age at the first dose:

  • Age 9–14 years: Administer a 2-dose series at 0 and 6–12 months. Minimum interval is 5 months. If a dose is given too soon, repeat the dose at least 12 weeks after the invalid dose and at least 5 months after the first dose.

  • Age ≥ 15 years: Administer a 3-dose series at 0, 1–2 months, and 6 months. Minimum intervals are 4 weeks between the first and 2nd dose, 12 weeks between the 2nd and 3rd dose, and 5 months between first and 3rd dose. If any dose is given too soon, repeat the dose at or after the minimum interval since the previous dose.

  • People who have completed a valid series with any HPV vaccine do not need additional doses.

  • For further guidance, see the ACIP's updated recommendations for the HPV vaccine.

ACIP = Advisory Committee on Immunization Practices; CDC = Centers for Disease Control and Prevention; N/A = not applicable; PRP-OMP = Neisseria meningitidis polyribosyl ribitol phosphate/outer membrane protein.

Adapted from the CDC: Catch-up immunization schedule for persons aged 4 months–18 years who start late or who are more than 1 month behind, United States, 2019. Available here.

More Information

Drugs Mentioned In This Article

Drug Name Select Trade
Gammagard S/D
SOLIRIS
Click here for Patient Education
NOTE: This is the Professional Version. CONSUMERS: Click here for the Consumer Version
Professionals also read

Also of Interest

Videos

View All
Overview of Persistent Truncus Arteriosus
Video
Overview of Persistent Truncus Arteriosus
3D Models
View All
Cystic Fibrosis: Defective Chloride Transport
3D Model
Cystic Fibrosis: Defective Chloride Transport

SOCIAL MEDIA

TOP