Trusted medical expertise in seconds.

Access 1,000+ clinical and preclinical articles. Find answers fast with the high-powered search feature and clinical tools.

Try free for 5 days
Evidence-based content, created and peer-reviewed by physicians. Read the disclaimer.

Immunization schedule

Last updated: August 23, 2021

Summarytoggle arrow icon

Vaccinations are among the most effective measures of preventive medicine. Especially in infants and young children, they can prevent potentially harmful diseases and hospitalization. Almost no one currently living in the US has seen vaccine-preventable diseases first-hand because their frequency has been dramatically decreased by vaccination. However, they persist worldwide and vaccination programs are essential to prevent future outbreaks of diseases like pertussis, mumps, and measles. In the US, immunization guidelines are published and updated every year by the Centers for Disease Control and Prevention (CDC) and Advisory Committee on Immunization Practices (ACIP). The schedule is designed to protect children when they are most vulnerable and individuals at high-risk before they are exposed to possibly life-threatening diseases.

Furthermore, international travelers are at risk of exposure to vaccine-preventable diseases depending on the region visited and the activities planned. Travelers should therefore seek advice about potential immunizations before departure. At a pretravel consultation, the traveler's prior immunizations, health conditions, and likely exposure to diseases while traveling should be taken into account. Information on travel vaccinations may be found on the CDC and the WHO websites.

General principles

  • Different vaccination types can be administered simultaneously (including live attenuated and inactivated vaccines) as specified in the ACIP immunization schedule.
  • Vaccines are given without dose adjustment for weight.
  • Missed doses should be caught up by simply continuing with the next doses required in the vaccine series.
  • Restarting the immunization series (i.e., from the first dose) if one or more doses are missed is never necessary, regardless of how much time has elapsed since the last dose.
  • The catch-up vaccinations are continued as per the minimum recommended interval between doses

Immunization schedule for birth to 18 months

Overview of immunization schedule for birth to 18 months
Birth 1 mo 2 mo 4 mo 6 mo 9 mo 12 mo 15 mo 18 mo
Hepatitis B vaccine (HepB) 1st dose (if infant > 2 kg) 2nd dose Catch-up 3rd dose

Diphtheria and tetanus toxoids, acellular pertussis

DTaP < 7 yrs

1st dose; minimum age 6 weeks

Exception: DTaP-inactivated poliovirus 4 years

2nd dose 3rd dose Catch-up 4th dose
Inactivated poliovirus vaccine (IPV) 1st dose, minimum age 6 weeks 2nd dose 3rd dose
Rotavirus vaccine (RV) 1st dose orally, minimum age 6 weeks 2nd dose 3rd dose
Hemophilus influenza type b vaccine (Hib) 1st dose, minimum age 6 weeks 2nd dose (3rd dose) Catch-up 3rd / 4th dose (booster dose) Catch-up
Pneumococcal conjugate (PCV13) 1st dose; minimum age 6 weeks 2nd dose 3rd dose Catch-up 4th dose Catch-up
Meningococcal conjugate High-risk groups, minimum age of 6 weeks for Hib-MenCY, 2 months for MenACWY-CRM ,and 9 months for MenACWY-D
Hepatitis A vaccine (HepA) 2-dose series at 12–24 months (time between doses: 6–18 months)
Influenza vaccine (IIV) Annual immunization: 1 or 2 doses
Measles, mumps, rubella vaccine (MMR) High risk groups prior to international travel: 1st dose at age 6–11 months 1st dose (minimum age is 12 months) Catch-up
Varicella vaccine (VAR) 1st dose Catch-up

Immunization schedule for 19 months to 18 years

Overview of immunization schedule for 19 months to 18 years
19-23 mos 2–3 years 4–6 years 7–10 years 11–12 years 13–15 years 16–18 years
Hepatitis B vaccine (HepB)
  • Catch-up
Diphtheria and tetanus toxoids, acellular pertussis DTaP < 7 yrs
  • Catch-up
  • 5th dose
Tdap ≥ 7 yrs
  • Catch-up
  • Single booster dose of Tdap is recommended
  • If catch-up immunizations with Tdap already administered, the single booster dose is not necessary for adolescents
Inactivated poliovirus vaccine (IPV)
  • Catch-up
  • 4th dose
  • Catch-up
Hemophilus influenza type b vaccine (Hib)
  • Catch-up
  • One dose recommended for high-risk groups
Pneumococcal vaccines Pneumococcal conjugate (PCV13)
  • Catch-up
  • Recommended for high-risk groups
Pneumococcal polysaccharide (PPSV23)
  • High-risk groups, minimum age is 2 years
Influenza vaccine IIV
LAIV
Hepatitis A vaccine (HepA)
  • 2-dose series at 12–24 months (time between doses: 6–18 months)
  • Catch-up
Meningococcal conjugate
  • High-risk groups
  • 1st dose
  • Catch-up
  • Booster dose at age 16 if first dose administered before 16th birthday
  • Catch-up immunization recommended for persons aged 13–18 years
Meningococcal B vaccine (MenB)
  • High-risk groups: 2 or 3 doses depending on the brand (minimum age: 10 years)
  • Based on clinical discretion: Adolescents and young adults aged 16–23 years to provide short-term protection against most strains of serogroup B meningococcal disease
Measles, mumps, rubella vaccine (MMR)
  • Catch-up
  • 2nd dose
  • Catch-up
Varicella vaccine (VAR)
  • Catch-up
  • 2nd dose
  • Catch-up
Human papillomavirus vaccine (HPV)
  • High-risk groups, minimum age 9 years
  • 2-dose series (can be ages 9–14 years)
  • 3-dose series for > 15 years
  • Catch-up

Adult recommendations and duration of protection

Overview immunization schedule for adults
Adult recommendations Duration of protection
Hepatitis B vaccine (HepB)
  • At least 20 years

Diphtheria and tetanus toxoids, acellular pertussis

  • For all adults ≥ 19 years who have never received a Tdap vaccine, provide a dose of Tdap (regardless of the interval since the last tetanus and diphtheria vaccine)
  • Booster doses of Td or Tdap every 10 years
  • All pregnant women should receive a single dose of Tdap at 27–36 weeks of gestation regardless of the interval since the last Tdap or Td vaccination.
  • Approx. 10 years
Rotavirus vaccine (RV)
  • Catch-up not routinely recommended for persons ≥ 18 years
  • Up to 3 years after completion of series
Hemophilus influenza type b vaccine (Hib)
  • Unknown; requires further investigation
Pneumococcal vaccines Pneumococcal conjugate (PCV13)
  • Not lifelong
Pneumococcal polysaccharide (PPSV23)
  • Recommended for all adults ≥ 65 years
  • Sequential PCV13 and PPSV23 are recommended for individuals age < 65 with certain high-risk conditions.
  • For adults age < 65 who are current smokers or have a chronic medical condition, PPSV23 vaccine alone is recommended.
  • Not lifelong
Inactivated poliovirus vaccine (IPV)
  • Catch-up not routinely recommended for persons ≥ 18 years
  • Probably lifelong after completion of series
Influenza vaccine (IIV, LAIV)
  • A yearly vaccine is recommended for all patients every flu season (Oct–April in northern hemisphere; May–Oct in southern hemisphere)
  • 1 season
Hepatitis A vaccine (HepA)
  • At least 25 years in adults and 14–20 years in children
Meningococcal conjugate
  • Repeat every 5 years in high-risk groups (e.g., patients with asplenia or complement component deficiency, complement inhibitor use, people traveling or residing in high-epidemic countries , microbiologists exposed to Neisseria meningitidis; first-year college students living in residence halls, military recruits)
  • Up to 5 years
Meningococcal B vaccine
  • Repeat every 2–3 years in high-risk groups
  • 2–3 years
Measles, mumps, rubella vaccine (MMR)
  • Probably lifelong
Varicella vaccine (VAR)
  • At least 10–20 years after completion of series
Zoster recombinant vaccine (RZV)
  • RZV: 2 doses in adults > 50 years (preferred over ZVL)
  • -
Human papillomavirus vaccine (HPV)
  • Catch-up immunization recommended for all adults < 26 years
    • 2 doses (0, 6–12 month schedule) in patients who began the immunization schedule at < 15 years
    • 3 doses (0, 1–2 month, 6 month schedule) in patients who began the immunization schedule ≥ 15 years or who are immunocompromised)
  • No evidence of weakened protection over time after completion of series

“HHating PeDs Immunization/Vaccination MmeHMorizing:” the childhood immunization schedule includes: HepB 0, 2, 6; Hib 2, 4, 6, 12–15; Pneumo: 2, 4, 6, 12–15; DTaP: 2, 4, 6, 15–18, 4–6 years; Td 10 years; IPV: 2, 4, 6, 4–6 years; Varicella 12–15, 4–6 years; MMR: 12–15, 4–6 years; HepA 2 years, Meningococcus 11–12 years.

References:[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]

Below is only a selection of recommendations. Not included are immunizations recommended for the US. For details on recommendations regarding specific countries, further diseases, vaccinations or drugs, see the CDC Yellow Book.

Overview of travel Immunizations
Immunization Schedule Minimum age Risk areas Recommendation Other
Japanese encephalitis vaccine (JE)
  • 2 doses, 28 days apart
  • Should be completed at least one week before exposure
  • Booster if last dose ≥ 1 year ago
  • 2 months
  • Southeast Asia
  • Recommended for travelers or US citizens living in endemic areas during periods of JE transmission
Yellow fever vaccine
  • 1 dose; at least 10 days before departure
  • 9 months
  • Africa, Central and South America
  • Recommended for all travelers or US citizens living in risk areas
  • Many African and South American countries require proof of vaccination from incoming travelers.
  • One dose provides lifelong protection.
Rabies vaccine
  • 3 doses: day 0, 7, and either 21 or 28 (depending on vaccine)
  • Provides protection within ∼ 2 weeks
  • none
  • Rabies is endemic on all continents except Antarctica. However, several countries are considered rabies-free.
  • May be recommended for travelers visiting countries with a high occurrence of animal rabies and low availability of antirabies biologics (e.g., countries in Africa, South America, and Southeast Asia)
  • Depends also on planned activities (e.g., caving, wildlife work in rabies-epizootic areas)
  • After being bitten by a mammal (e.g., dog, cat, monkey) persons who have been previously vaccinated should get 2 more doses of rabies vaccine (days 0 and 3). Rabies immune globulin is not required.
Typhoid and paratyphoid fever vaccine
  • Inactivated typhoid vaccine: 1 dose
    • At least 2 weeks before traveling
    • Booster dose every 2 years
  • Live typhoid vaccine: 4 doses; day 0, 3, 5, 7);
    • At least 1 week before traveling
    • Booster dose every 5 years
  • Common in most developing countries, especially in Southern Asia
  • Recommended for travelers with exposure to potentially contaminated foods and beverages
  • Persons with intimate exposure to a chronic carrier of Salmonella typhi
  • The vaccine can only prevent illness in about ¾ of cases.

Meningococcal conjugate

  • Children at 2 months of age: MenACWY-CRM as a 4-dose series at 2, 4, 6, and 12 months of age
  • Children at 7–23 months of age: MenACWY-CRM or MenACWY-D as a 2-dose series
  • Travelers 2–56 years: 1 dose MenACWY-CRM or MenACWY-D
  • Travelers > 56 years: 1 dose of meningococcal polysaccharide vaccine (groups A, C, Y, W combined)
  • 2 months
  • Sub-Saharan Africa
  • A quadrivalent meningococcal conjugate vaccination (e.g., MenACWY-CRM or MenACWY-D; protects against serogroups A, C, W, and Y) is recommended for persons traveling or residing in hyperendemic or epidemic countries who are in close contact with natives.
  • Travelers aged ≥ 2 years going to Saudi Arabia on a pilgrimage to Mecca are required by the Saudi government to provide proof of vaccination with a quadrivalent meningococcal vaccine in the last 3 years. Documentation of 2 doses of a meningococcal vaccine against serogroup A is required for travelers aged 3 months to 2 years.

References:[17][18][19][20][21][22][23][24][25]

Overview of pathogens affecting unvaccinated children
Pathogen Disease Clinical features Treatment
Measles virus
Rubella virus
  • Symptomatic treatment
Varicella zoster virus
Mumps virus
  • Symptomatic treatment
Corynebacterium diphtheriae
Haemophilus influenzae type b
Streptococcus pneumoniae
Neisseria meningitidis
Poliovirus
Clostridium tetani
Bordetella pertussis
  • Intense paroxysmal coughing (often occurring at night)
    • Followed by a deep and loud inhalation or high-pitched whooping sound
    • Often followed by posttussive vomiting
Hepatitis A virus
Hepatitis B virus
  1. Child and Adolescent Schedule. https://www.cdc.gov/vaccines/schedules/hcp/imz/child-adolescent.html. Updated: February 3, 2020. Accessed: June 23, 2020.
  2. Epidemiology and Prevention of Vaccine-Preventable Diseases.
  3. Ask the Experts About Rotavirus Vaccines. http://www.immunize.org/askexperts/experts_rota.asp. Updated: July 22, 2016. Accessed: March 23, 2017.
  4. Ask the Experts About Hib Vaccines. http://www.immunize.org/askexperts/experts_hib.asp. Updated: January 29, 2016. Accessed: March 24, 2017.
  5. Briere EC. Food and Drug Administration approval for use of Hiberix as a 3-dose primary Haemophilus influenzae type b (Hib) vaccination series. Morb Mortal Wkly Rep. 2016; 65 (16): p.418-419. doi: 10.15585/mmwr.mm6516a3 . | Open in Read by QxMD
  6. Expanding the potential impact of Haemophilus influenzae type b vaccines (Hib) by optimizing immunization schedules. http://www.who.int/immunization/sage/meetings/2013/april/1_Hib_summary_of_evidence.pdf. Updated: March 26, 2013. Accessed: March 24, 2017.
  7. Hepatitis B FAQs for Health Professionals. https://www.cdc.gov/hepatitis/hbv/hbvfaq.htm#D1. Updated: August 4, 2016. Accessed: March 24, 2017.
  8. HPV Vaccine Information For Young Women. https://www.cdc.gov/std/hpv/stdfact-hpv-vaccine-young-women.htm. Updated: January 3, 2017. Accessed: March 23, 2017.
  9. Meningococcal Vaccination: What Everyone Should Know. https://www.cdc.gov/vaccines/vpd/mening/public/index.html. Updated: December 9, 2016. Accessed: March 24, 2017.
  10. MacNeil JR, Rubin L, Folaranmi T, Ortega-Sanchez IR, Patel M, Martin SW. Use of Serogroup B Meningococcal Vaccines in Adolescents and Young Adults: Recommendations of the Advisory Committee on Immunization Practices, 2015. Morb Mortal Wkly Rep. 2015; 64 (41): p.1171-1176. doi: 10.15585/mmwr.mm6441a3 . | Open in Read by QxMD
  11. MMR vaccine FAQs. http://www.nhs.uk/conditions/vaccinations/pages/mmr-questions-answers.aspx. Updated: October 4, 2015. Accessed: March 24, 2017.
  12. Varicella Vaccine Effectiveness and Duration of Protection. https://www.cdc.gov/vaccines/vpd-vac/varicella/hcp-effective-duration.htm. Updated: August 30, 2012. Accessed: March 24, 2017.
  13. Van Damme P. Long-term Protection After Hepatitis B Vaccine. J Infect Dis. 2016; 214 (1): p.1-3. doi: 10.1093/infdis/jiv750 . | Open in Read by QxMD
  14. Vaccine Non-Responders. http://www.hepb.org/prevention-and-diagnosis/vaccination/vaccine-non-responders/. Updated: January 1, 2018. Accessed: March 29, 2018.
  15. Tomczyk S, Bennett NM, Stoecker C, et al. Use of 13-valent pneumococcal conjugate vaccine and 23-valent pneumococcal polysaccharide vaccine among adults aged ≥65 years: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR. 2014; 63 (37): p.822-825.
  16. Viral Hepatitis - Hepatitis A Questions and Answers for Health Professionals. https://www.cdc.gov/hepatitis/hav/havfaq.htm#B4. Updated: October 25, 2017. Accessed: March 29, 2018.
  17. Fischer M, Lindsey N, Staples JE, Hills S. Japanese encephalitis vaccines: recommendations of the Advisory Committee on Immunization Practices (ACIP). Morb Mortal Wkly Rep. 2010; 59 (RR01): p.1-27.
  18. Infectious Diseases Related to Travel - Japanese Encephalitis. https://wwwnc.cdc.gov/travel/yellowbook/2016/infectious-diseases-related-to-travel/japanese-encephalitis. Updated: July 10, 2015. Accessed: March 24, 2017.
  19. Travelers' Health - Yellow Fever. https://wwwnc.cdc.gov/travel/diseases/yellow-fever. Updated: July 10, 2015. Accessed: March 24, 2017.
  20. Clinical Update: Yellow Fever Vaccine Booster Doses. https://wwwnc.cdc.gov/travel/news-announcements/yf-vax-booster. Updated: July 21, 2015. Accessed: March 24, 2017.
  21. Select Destinations - Saudi Arabia: Hajj/Umrah Pilgrimage. https://wwwnc.cdc.gov/travel/yellowbook/2018/select-destinations/saudi-arabia-hajj-umrah-pilgrimage. Updated: June 12, 2017. Accessed: March 29, 2018.
  22. Infectious Diseases Related to Travel - Meningococcal Disease. https://wwwnc.cdc.gov/travel/yellowbook/2018/infectious-diseases-related-to-travel/meningococcal-disease. Updated: June 12, 2017. Accessed: March 29, 2018.
  23. Rabies Vaccine. http://www.who.int/ith/vaccines/rabies/en/. Updated: January 1, 2018. Accessed: March 29, 2018.
  24. Importation - Rabies-Free Countries and Political Units. https://www.cdc.gov/importation/rabies-free-countries.html. Updated: January 23, 2017. Accessed: March 29, 2018.
  25. Infectious Diseases Related to Travel - Typhoid & Paratyphoid Fever. https://wwwnc.cdc.gov/travel/yellowbook/2018/infectious-diseases-related-to-travel/typhoid-paratyphoid-fever. Updated: May 31, 2017. Accessed: March 29, 2018.
  26. Herold G. Internal Medicine. Herold G ; 2014