Baby's first-year vaccine schedule (CDC + WHO overview)

The immunization record is one of the most important documents of the first year. In the United States, the CDC/ACIP schedule lays out which vaccines your baby receives, when, and why — and the WHO publishes a parallel global schedule used by most national health systems worldwide. This guide walks through what your baby gets at each age, what each vaccine protects against, what side effects to expect, and what to do if you fall behind. Built on CDC, AAP and WHO recommendations.

Country covered in this guide: United States. Schedule from the CDC / ACIP 2025 recommendations, aligned with AAP HealthyChildren guidance. The article also references the WHO global schedule used by most national health systems worldwide. Official sources: CDC — Child & Adolescent Immunization Schedule · AAP HealthyChildren — Immunizations.

Living elsewhere? National schedules differ — always check the one issued by your country's health authority. Quick links: UK → NHS vaccination schedule · Canada → Public Health Agency of Canada · Australia → National Immunisation Program · India → Indian Academy of Pediatrics · Other → WHO summary tables.

Why vaccinate in the first year

Newborns arrive with passive antibodies from the mother (transferred through the placenta in the last weeks of pregnancy) and, if breastfed, ongoing protection from antibodies in breast milk. That defense, however, fades quickly through the first 6 months — exactly when the baby's immune system is still developing.

Vaccines work by teaching the immune system to recognize and respond to viruses and bacteria before the disease occurs. In the first year, your baby receives most of the primary doses against the diseases that historically caused the most deaths or lifelong disability in young children: hepatitis B, diphtheria, tetanus, pertussis (whooping cough), polio, Haemophilus influenzae type b, pneumococcus, rotavirus, influenza, measles, mumps, rubella, varicella, hepatitis A.

According to the WHO, childhood vaccination prevents 3.5–5 million deaths per year worldwide.

CDC/ACIP schedule for the first year (US)

The schedule below follows the 2025 CDC/ACIP recommendations for healthy infants in the United States. Some doses are given in a window (e.g. 2–3 months for the first rotavirus dose), and combination vaccines may differ between providers.

Note: this is the routine US schedule. If you live elsewhere, follow your national schedule (NHS in the UK, RKI in Germany, AEP in Spain, HAS in France, PNI in Brazil, etc.). The WHO schedule used by many low- and middle-income countries adds BCG at birth for tuberculosis prevention — the US does not give BCG routinely because the TB burden is low.

Vaccine by vaccine: what it protects against and how it reacts

At birth

Hepatitis B (1st dose). Ideally given within the first 24 hours of life. Protects against hepatitis B virus infection, which can cause chronic hepatitis, cirrhosis and liver cancer years later. Following doses are at 1–2 months and 6–18 months.

In countries that follow the WHO schedule, BCG is also given at birth (or in the first month) to protect against severe forms of tuberculosis (tuberculous meningitis, miliary TB).

2, 4 and 6 months

These visits are the heaviest in shots — and also the most important.

DTaP — Diphtheria, Tetanus, acellular Pertussis (whooping cough). Three doses build the primary series; boosters follow at 15–18 months and 4–6 years. Acellular pertussis has fewer reactions than the older whole-cell formulation; both are safe.

IPV — Inactivated Polio Vaccine (injectable). Replaced the oral polio vaccine in the US in 2000. Protects against the paralysis of poliomyelitis.

Hib — Haemophilus influenzae type b. Protects against meningitis, epiglottitis and severe pneumonia caused by Hib. Number of doses depends on brand (3 or 4).

PCV15 (pneumococcal conjugate). Protects against 15 serotypes of Streptococcus pneumoniae, the leading cause of pneumonia, otitis media, meningitis and bacteremia in young children. The 12–15 month dose is the booster.

Rotavirus (oral drops). Protects against rotavirus gastroenteritis, which used to be the leading cause of severe diarrhea and dehydration in babies before vaccination. The series has a strict age window: the first dose between 6 weeks and 14 weeks 6 days; the last dose by 8 months 0 days. Doses outside that window cannot be given (slightly increased risk of intussusception). If your baby spits up shortly after the oral dose, do NOT repeat — just continue with the next scheduled dose.

Influenza (from 6 months). Annual flu shot. The first season requires two doses 4 weeks apart; subsequent years a single annual dose.

HepB (3rd dose). Often given at the 6-month visit; the third dose can be anywhere from 6 to 18 months.

12–15 months

MMR — Measles, Mumps, Rubella. Live attenuated vaccine. Expected reaction: fever appearing 5 to 12 days after the dose (not a "delayed reaction" — it's the cycle of the attenuated virus), sometimes with a mild rash that fades on its own. Measles has resurged in regions with low coverage — staying current matters for community protection.

Varicella (chickenpox). Live attenuated vaccine. First dose at 12–15 months, second at 4–6 years.

Hepatitis A. Two doses at least 6 months apart, starting at 12 months. Protects against hepatitis A, transmitted by contaminated food and water.

Hib booster and PCV15 booster complete the first-year cycle.

What to expect in the 48 hours after a shot

Most side effects appear in the first 24–48 hours and resolve on their own. They are signs that the immune system is doing its job — they do not mean the vaccine "did harm".

Red flags — when to seek care

Although rare, certain signs require immediate medical evaluation:

• Fever above 40°C (104°F) or fever that does not respond to fever reducers
• Inconsolable crying for more than 3 hours continuously
• Seizure
• Severe lethargy — limp baby, hard to wake
• Extensive limb swelling (whole thigh or arm swollen and warm)
• Anaphylactic reaction: generalized hives, swelling of face/lips, breathing difficulty, extreme paleness — typically within the first 30 minutes, which is why some clinics ask you to wait before leaving

These events are extremely rare (anaphylaxis: roughly 1 case per 1 million doses, per WHO data), but they should be reported as a vaccine adverse event (in the US, via the VAERS system) so the CDC and FDA can monitor vaccine safety.

If you fall behind

Good news: the schedule is cumulative. Doses your baby has already received still count. You don't need to restart any series — just catch up on what's missing.

What to do:

1. Bring the immunization record to your pediatrician. They will follow the CDC catch-up schedule to plan the next visits.
2. Sooner is better, especially for vaccines with strict age limits like rotavirus.
3. Don't skip doses thinking "they got one already, that's enough". Long-term immunity depends on the complete series.
4. Multiple shots in one visit are safe — the baby can receive several at once in different sites without weaker response or more serious reactions.

The CDC and AAP both reinforce: the diseases vaccines prevent are far more dangerous than the vaccines themselves. Measles, pertussis and Haemophilus meningitis have re-emerged in pockets of low coverage in the past decade.

Common myths — and what the evidence says

• "Vaccines cause autism" — Myth. The 1998 Wakefield paper was retracted for fraud; the author lost his medical license. Subsequent studies with millions of children (Hviid et al., Annals of Internal Medicine, 2019, with 657,000 Danish children) have ruled out any association.
• "Too many vaccines at once overload the immune system" — Myth. A baby encounters trillions of antigens daily through the environment alone; the entire vaccine schedule represents a tiny fraction. Combination shots are designed to be safe and effective together.
• "If they have colic or reflux, better delay" — Myth. Colic and reflux do not contraindicate vaccination.
• "Breastfed babies don't need vaccines" — Myth. Breast milk protects against several infections, but it does not replace vaccines. The two complement each other.
• "Pre-medicating with acetaminophen prevents fever" — Not recommended. Studies have shown that prophylactic acetaminophen reduces immune response to some vaccines. Use only after fever appears.

How to organize the immunization record in the first year

A few habits that help:

• Schedule the next visit before you leave the current one.
• Take a photo of the record after each shot — losing the paper card is a real problem when reconstructing history later.
• Note how the baby reacted (fever? how long? site pain?). It helps your pediatrician personalize the next dose.
• If traveling internationally, especially to regions with active outbreaks (measles, polio, yellow fever), check in advance whether the schedule is up to date or whether additional travel vaccines are recommended.

Fridge-magnet summary

• Birth: HepB (and BCG in WHO-schedule countries)
• 2 / 4 / 6 months: DTaP, IPV, Hib, PCV15, rotavirus
• 6 months: annual flu starts
• 12–15 months: MMR, varicella, HepA, Hib + PCV15 boosters

Staying on schedule is the single highest-impact preventive action of the first year. When in doubt about a specific dose, talk to your pediatrician or check the CDC/WHO schedule directly — never social media or influencers.