• Clinical science

Immunization schedule (Vaccination schedule)


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.

ACIP immunization schedule

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

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 Annual immunization: 1 or 2 doses Annual immunization: 1 dose (> 9 years)
LAIV Annual immunization: 1 or 2 doses (2–9 years) Annual immunization: 1 dose (> 9 years)
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 3-dose series for > 15 years Catch-up

Adult recommendations and duration of protection

Adult recommendations Duration of protection
Hepatitis B vaccine (HepB)
  • At least 20 years

Diphtheria and tetanus toxoids, acellular pertussis (DTaP)

  • Booster doses of Td 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)
  • 2 doses of HepA vaccine separated by 6–18 months for high risk groups (e.g., travelers to endemic countries, users of recreational drugs, men who have sex with men, patients with chronic liver disease)
  • 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) or zoster live vaccine (ZVL)
  • RZV: 2 doses in adults > 50 years (preferred over ZVL)
  • ZVL: 1 dose in adults > 60 years
  • -
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

To remember the childhood immunization schedule think: HHating PeDs Immunization/Vaccination MmeHMorizing: 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, MMR: 12–15, 4–6 years, HepA 2 years, Meningococcus 11–12 years


Immunizations for travel

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.

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
  • There is currently no efficacy data available for the vaccine.
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.