What is the routine immunization schedule for a healthy newborn and infant without contraindications?

Neonatal and Infant Vaccination Timeline

Birth (Within 24 Hours)

All medically stable newborns weighing ≥2,000 g should receive the first dose of hepatitis B vaccine before hospital discharge, regardless of maternal HBsAg status. 1, 2

• Infants born to HBsAg-positive mothers must receive both hepatitis B vaccine and 0.5 mL hepatitis B immune globulin (HBIG) within 12 hours of birth at separate injection sites, regardless of birth weight 1, 2
• Infants born to mothers with unknown HBsAg status receive hepatitis B vaccine within 12 hours; maternal blood is drawn immediately, and if positive, HBIG is administered as soon as possible but no later than 7 days of age 1, 2
• Preterm infants <2,000 g born to HBsAg-negative mothers should defer the birth dose until 1 month of chronological age or hospital discharge 1, 2
• Only monovalent hepatitis B vaccine should be used for the birth dose; combination vaccines are not appropriate 1, 2

2 Months (Minimum Age: 6 Weeks)

At 2 months of chronological age, infants receive their first comprehensive set of vaccines simultaneously to provide early protection during the highest-risk period. 2

• DTaP (Diphtheria, Tetanus, Pertussis) – first dose 2
• Hib (Haemophilus influenzae type b) – first dose 2
• PCV (Pneumococcal conjugate vaccine) – first dose 2
• IPV (Inactivated poliovirus) – first dose 2
• Rotavirus – first dose (must be initiated between 6 weeks and 14 weeks 6 days; initiation after this window is contraindicated due to intussusception risk) 2
• Hepatitis B – second dose (minimum 4 weeks after first dose) 2

4 Months

All vaccines from the 2-month visit are repeated at 4 months, maintaining a minimum 4-week interval between doses. 2

• DTaP – second dose 2
• Hib – second dose 2
• PCV – second dose 2
• IPV – second dose 2
• Rotavirus – second dose 2

6 Months

The 6-month visit completes the primary infant series for most vaccines and initiates influenza vaccination. 2, 3

• DTaP – third dose 2
• Hib – third dose (not required if PRP-OMP vaccine was used at 2 and 4 months) 2, 3
• PCV – third dose 2, 3
• Rotavirus – third dose if using RotaTeq (must be completed by 8 months of age) 2, 3
• Hepatitis B – third dose (minimum 8 weeks after second dose, minimum 16 weeks after first dose, and infant must be ≥24 weeks old) 1, 2
• Influenza – first dose (annual vaccination; children <9 years receiving for the first time need two doses ≥4 weeks apart) 2, 3

12-15 Months

Live-virus vaccines are introduced at 12 months along with booster doses of previously administered vaccines. 2

• MMR (Measles, Mumps, Rubella) – first dose (minimum age 12 months) 2
• Varicella – first dose (minimum age 12 months) 2
• Hepatitis A – first dose (second dose 6 months later) 2
• DTaP – fourth dose (can be given as early as 12 months if ≥6 months have elapsed since third dose) 1, 2
• Hib – fourth dose (final booster) 2
• PCV – fourth dose (final booster) 2

18 Months

• DTaP – fourth dose if not given at 12-15 months 2

4-6 Years (School Entry)

Preschool boosters complete the childhood vaccination series before kindergarten entry. 2

• DTaP – fifth dose (final childhood dose; must be given after age 4 years) 2
• IPV – fourth dose (not required if third dose was given at ≥4 years of age) 2
• MMR – second dose (may be given earlier if ≥28 days after first dose) 2
• Varicella – second dose (may be given earlier if ≥3 months after first dose) 2

11-12 Years (Adolescent Visit)

• Tdap (Tetanus, diphtheria, acellular pertussis) – single booster dose 1, 2
• HPV (Human papillomavirus) – two-dose series separated by at least 5 months if initiated before age 15 years 1
• Meningococcal conjugate (MenACWY) – first dose 1

Critical Timing Principles

Vaccines should be administered at chronological age, not corrected gestational age, for all infants including preterm infants. 2

• Minimum intervals between doses must be maintained to ensure adequate immune response 2
• Simultaneous administration of multiple vaccines is safe, does not increase adverse events, and significantly improves completion rates 2, 4
• Any dose not given at the recommended age should be administered at the next possible visit 1
• Never restart a vaccine series regardless of time elapsed between doses; continue where you left off 4

Common Pitfalls to Avoid

• Do not delay vaccination for minor illnesses such as mild upper respiratory infections, diarrhea, or low-grade fever—these are not contraindications 4
• Do not use corrected age for preterm infants when scheduling vaccines; use chronological age 2
• Do not miss the rotavirus window: initiation after 14 weeks 6 days is contraindicated, and the series must be completed by 8 months 2, 3
• Do not defer the birth dose of hepatitis B vaccine in term infants ≥2,000 g without documented maternal HBsAg-negative status and physician order 1, 2

Special Populations

HIV-infected infants receive all inactivated vaccines on the standard schedule; MMR may be given to asymptomatic or mildly symptomatic children but is contraindicated in severely immunosuppressed children; varicella is only for asymptomatic, non-immunosuppressed HIV-infected children 1, 2

Preterm infants follow the same chronological schedule as term infants, with the exception of hepatitis B birth dose deferral for infants <2,000 g born to HBsAg-negative mothers 1, 2