Baby Vaccine Schedule

The six visits that carry the baby schedule

Almost every infant vaccine lands in one of six well-child visits: 2, 4, 6, 12, 15 and 18 months. The CDC child and adolescent immunization schedule lays them out by age, and the pattern is built around two things: when a baby's immune system can respond to a vaccine, and when the protection from the mother starts to fade.

The spacing is not arbitrary. The first doses arrive at 2 months because antibodies passed during pregnancy protect a newborn for roughly the first two months. The gaps of 4 to 8 weeks between the early doses let the immune response build without overlapping too much. The 12-month cluster waits until the immune system handles live vaccines such as MMR, which is why those shots cannot be pulled earlier just for convenience.

Six visits, 10 diseases, and a needle count that depends on which products your pediatrician stocks. The calculator above turns a birth date into the actual calendar dates, and it shows the injection count both ways.

What is given at 2, 4 and 6 months

The first three visits carry the heaviest load. Each one covers the same core set, with small differences as the series builds.

• DTaP covers diphtheria, tetanus and pertussis, the last of which is whooping cough. Three doses by 6 months, a fourth at 15 to 18 months, and a fifth at 4 to 6 years.
• Polio, or IPV. One injection at each of the first three visits, with a fourth at 4 to 6 years.
• Hib protects against Haemophilus influenzae type b, a cause of meningitis in young children. Three doses in the first six months and a booster at 12 to 15 months.
• Pneumococcal, or PCV. Four doses: 2, 4, 6 and 12 to 15 months.
• Rotavirus. An oral vaccine, not a shot, given at 2, 4 and 6 months. The first dose has to happen before 15 weeks of age.
• Hepatitis B. The first dose is usually given at the hospital within 24 hours of birth, with the second at 1 to 2 months and the third anywhere from 6 to 18 months.

Count the injections and the 2-month visit is 5, with 1 oral dose alongside. The 4-month and 6-month visits are 4 injections each plus the oral dose. A baby who also gets the yearly flu vaccine from 6 months adds 1 or 2 more, depending on whether it is a first flu season.

The 12, 15 and 18 month visits

The second year is lighter on needles and heavier on new diseases. The 12-month visit is the busiest of the three.

At 12 months a baby gets MMR, chickenpox, a pneumococcal booster and a Hib booster, which is 4 injections. If the practice stocks ProQuad, the combined MMR and chickenpox product, it is 3. Hepatitis A also starts in this window, anywhere from 12 to 23 months, with the second dose at least 6 months later.

At 15 months there is one injection: the fourth DTaP. Many practices fold this into the 18-month visit, and the CDC window runs to 18 months, so a DTaP at 17 months counts.

At 18 months the hepatitis A series finishes if it started at 12 months, and the fall flu shot lands here for a baby born in spring. That is 2 injections, and the visit doubles as the autism and development screening checkpoint that most pediatric practices run between 18 and 24 months.

Put together, the three visits add 7 injections, which is where the 20-injection total comes from when every antigen goes in separately.

Combination shots versus separate shots

A combination vaccine packs several antigens into one syringe. The antigen count does not change, and the protection does not change. What changes is the number of needle sticks and the number of vials a practice has to keep in stock.

The two products that matter most in the first year are Pediarix, which combines DTaP, polio and hepatitis B, and Pentacel, which combines DTaP, polio and Hib. Either one turns the 2-month visit from 5 injections into 3. At 12 months, ProQuad combines MMR and chickenpox and turns 4 injections into 3.

Over the full schedule the difference is about 5 injections: roughly 20 with separate antigens, 15 with combinations. For a baby that is 5 fewer pokes, and for a parent it is 5 fewer holds on the exam table.

The trade-offs are practical rather than medical. A practice may not stock every combination, insurance coverage varies by product, and some combinations cannot be used at certain ages because the antigen doses are fixed. A pediatrician may also prefer separate shots when one component needs to be delayed, since a combination cannot be split apart. None of these choices changes the date of the next visit.

The whole schedule in one table

This is the six-visit pattern with the injection count for each route. The oral rotavirus dose is listed separately because it is swallowed, not injected.

Two visits in this table are flexible by design. Hepatitis B can finish at any point from 6 to 18 months, and hepatitis A can start at any point from 12 to 23 months. That flexibility is why two babies the same age can have different shot counts on the same day.

Behind schedule: how catch-up works

A missed visit does not restart a series. This is the single most common worry at a late checkup, and the rule is simple: the doses already given still count, and the series resumes at the next dose.

What matters is the minimum interval between doses, not the calendar. If the 4-month visit is skipped and the baby shows up at 7 months, the 4-month doses can be given then, and the 6-month doses follow 4 weeks later. The schedule notes list the minimum age for each dose and the minimum gap to the next one.

Two vaccines have hard ceilings rather than floors. Rotavirus cannot be started after 14 weeks and 6 days, and the series has to finish by 8 months, so a baby who falls far behind may skip that one entirely. Everything else can be caught up later, and a pediatrician will usually compress the missed doses into the next two or three visits rather than adding extra appointments.

One caution on early doses: a shot given before the minimum age does not count and has to be repeated. That is why a practice will not move the 12-month MMR up to 10 months for a family trip without a specific travel plan in writing.

The day after a shot

Most reactions are small and short. A sore thigh, a low fever, fussiness and extra sleep are the usual pattern, and they show the immune system is responding rather than that something went wrong.

• Fever. Up to 100.4 F in the first 24 to 48 hours is common, and about 1 in 4 babies runs one after DTaP. Infant acetaminophen or ibuprofen dosed by weight helps, and ibuprofen is only for babies over 6 months.
• Soreness. A red, warm spot at the injection site can last 2 or 3 days. A cool cloth and extra holding do more than anything else.
• Fussiness. Expect a rough evening after the 2-month and 4-month visits, and a calmer one after the boosters.
• When to call. A fever above 100.4 F lasting more than 48 hours, any fever in a baby under 3 months, a cry that will not stop for 3 hours, or swelling that spreads past the thigh.

Serious reactions are rare, and they are reportable. The Vaccine Adverse Event Reporting System collects them, and a pediatrician can file a report on a family's behalf. Keep the visit date and the product name from the shot record, because both are needed for a report or for a school form later.

Where to get the shots and what to bring

The pediatrician's office is the default, and it is the best choice for a baby under 2 because the visit also covers weight, length, feeding and development. A local health department clinic is the usual alternative, and many run evening hours for working parents. Retail pharmacies rarely vaccinate infants, and some states set a minimum age of 3 or 5 for pharmacy shots.

Bring three things: the shot record, the insurance card and a list of any reaction after a previous dose. If the record is missing, a pediatrician can often pull it from a state immunization registry, which most states maintain and which keeps a consolidated history across providers.

Cost should not decide the schedule. The Vaccines for Children program covers the full series at no cost for children who are uninsured, underinsured, on Medicaid or Native American, and most private plans cover infant vaccines with no copay as preventive care. Ask at the front desk before the visit rather than after, since the billing code for a combination product can differ from the separate shots.

This page is a planning reference built from the published CDC schedule, not medical advice. Your pediatrician may adjust a date for a premature birth, an immune condition or a missed visit, and the office record is the version that counts.