The immunization schedule is a set of CDC recommendations that maps out which vaccines you need and exactly when to get them, from birth through adulthood. It covers more than a dozen vaccines for children and continues with boosters and new vaccines well into your 60s and beyond. The schedule is updated annually and grouped by age: children (birth through 6 years), adolescents (7 through 18), and adults (19 and older).
Birth Through 18 Months
Vaccines start on the day a baby is born with the first dose of hepatitis B. Over the next 18 months, the schedule is packed with the highest concentration of doses a person will ever receive, because infants are most vulnerable to serious infections. Here’s what’s recommended during this window:
- Hepatitis B: 3 doses at birth, 1 to 2 months, and 6 to 18 months
- Rotavirus: 2 or 3 doses (depending on the brand) starting at 2 months, with additional doses at 4 and sometimes 6 months
- DTaP (diphtheria, tetanus, whooping cough): first 3 of a 5-dose series at 2, 4, and 6 months
- Hib (bacterial meningitis): 3 to 4 doses starting at 2 months, with a booster at 12 to 15 months
- Pneumococcal: 4 doses at 2, 4, 6, and 12 to 15 months
- Polio: first 3 of a 4-dose series at 2, 4, and 6 to 18 months
- MMR (measles, mumps, rubella): first dose at 12 to 15 months
- Chickenpox: first dose at 12 to 15 months
- Hepatitis A: 2-dose series starting at 12 months, with the second dose at least 6 months later
Many of these vaccines are given as combination shots, so a single injection can cover multiple diseases at once. Your child won’t receive a separate needle for every vaccine listed above.
Toddler Through Elementary School
Between ages 15 months and 6 years, the schedule focuses on boosters that strengthen the immunity built during infancy. The fourth dose of DTaP is given at 15 to 18 months, and the fifth and final dose comes at 4 to 6 years, right before kindergarten. Polio gets its fourth dose at 4 to 6 years as well. The second doses of MMR and chickenpox are also given at 4 to 6 years.
This is often when parents notice a cluster of shots at the pre-kindergarten checkup. That visit typically covers the final DTaP, polio, MMR, and chickenpox doses, which is why many schools require proof of these vaccines before enrollment.
Preteens and Teens
The 11- to 12-year-old checkup introduces three important vaccines. The first is a tetanus, diphtheria, and whooping cough booster (Tdap), which replaces the childhood DTaP. The second is HPV, which protects against cancers caused by human papillomavirus. Most adolescents need a 2-dose HPV series if they start before age 15. Those who start at 15 or older, or who have weakened immune systems, need 3 doses.
The third is the meningococcal ACWY vaccine, which protects against bacterial meningitis. All preteens get one dose at 11 to 12, with a booster at 16 because protection fades over time. Teens who get their first dose at 16 or later don’t need the booster. A separate meningococcal B vaccine is available for teens preferably between 16 and 18 years old, though it’s based on individual decision-making rather than a blanket recommendation.
Adult Vaccines by Age
The adult schedule is less intensive but far from empty. A tetanus and diphtheria booster is recommended every 10 years for all adults. The flu vaccine is annual. COVID-19 vaccination is recommended yearly for everyone 6 months and older, with most adults ages 12 to 64 needing one dose per season. Adults 65 and older are recommended to receive two COVID-19 doses, spaced six months apart.
At age 50, two new vaccines enter the picture. The shingles vaccine is a 2-dose series recommended for all adults 50 and older, regardless of whether they remember having chickenpox. Pneumococcal vaccines also become routine, with a single dose of PCV20 or PCV21 completing the series for most people. If PCV15 is used instead, a follow-up dose of a different pneumococcal vaccine is needed about a year later. Adults younger than 50 with certain risk factors, such as chronic heart or lung disease, diabetes, or a weakened immune system, may also need pneumococcal vaccination earlier.
Vaccines During Pregnancy
Pregnant people have their own mini-schedule. The Tdap vaccine is recommended during every pregnancy, typically in the third trimester, so that protective antibodies transfer to the baby before birth. The flu vaccine is also recommended during any trimester of pregnancy.
RSV is a newer addition. Pregnant people can receive a single RSV vaccine dose during weeks 32 through 36 of pregnancy, given between September and January, to protect their newborn during RSV season. The timing matters: getting vaccinated after 36 weeks and 6 days is not recommended because there isn’t enough time for antibodies to cross the placenta. If the mother isn’t vaccinated, the infant can instead receive an RSV antibody injection (nirsevimab) during October through March.
Catching Up on Missed Vaccines
If your child has fallen behind, the CDC publishes a catch-up schedule with minimum intervals between doses so vaccines can be given on an accelerated timeline. The spacing rules vary by vaccine. For hepatitis B, doses must be at least 4 weeks apart for the first two, and the third dose must come at least 8 weeks after the second and at least 16 weeks after the first. For MMR, you only need 4 weeks between the two doses. Polio requires 4 weeks between the first three doses and 6 months before the final dose, which should not be given before age 4.
These minimum intervals allow a child who missed early vaccines to get fully caught up in a matter of months rather than years. Adults who were never vaccinated or lack records can also catch up. The hepatitis B series, MMR, chickenpox, and polio vaccines all have adult catch-up options.
Adjusted Schedules for Higher-Risk Groups
People with weakened immune systems, whether from medication, organ transplant, or HIV, often need extra doses or earlier vaccination. For example, HPV normally requires 2 doses for teens, but immunocompromised individuals need 3 regardless of age at first dose. The shingles vaccine is recommended as early as age 19 for people with immune-suppressing conditions, rather than the usual age 50. Stem cell transplant recipients need a completely fresh 3-dose Hib series starting 6 to 12 months after transplant, regardless of what they received before.
People with diabetes who are 60 or older are specifically recommended to get vaccinated against hepatitis B. Those with insulin-dependent diabetes or chronic heart disease are also flagged as higher risk for severe RSV, which may influence whether they receive that vaccine.
Travel Vaccines
International travel can add vaccines to your schedule that aren’t part of the routine U.S. recommendations. Hepatitis A, typhoid, yellow fever, Japanese encephalitis, cholera, and rabies are all potentially recommended depending on your destination. Some of these, like yellow fever, require a certificate of vaccination for entry into certain countries. The CDC recommends checking travel-specific vaccine guidance at least 4 to 6 weeks before departure, since some series require multiple doses spaced weeks apart.