What vaccines are recommended for a 4-month-old infant?

Recommended Vaccines at Four Months of Age

At four months of age, infants should receive the second doses of DTaP, IPV, Hib, pneumococcal conjugate vaccine (PCV), rotavirus vaccine, and potentially the second dose of hepatitis B vaccine if not already completed. 1, 2

Core Vaccine Series at 4 Months

The following vaccines are recommended as part of the routine immunization schedule:

DTaP (Diphtheria, Tetanus, Acellular Pertussis)

• The second dose of DTaP should be administered at 4 months of age, with a minimum interval of 4 weeks after the first dose given at 2 months 1
• This is part of a 3-dose primary series given at 2,4, and 6 months 1, 2

IPV (Inactivated Poliovirus Vaccine)

• The second dose of IPV is due at 4 months of age 1
• All children should receive IPV at 2,4,6-18 months, and 4-6 years as part of the all-IPV schedule recommended for routine childhood vaccination in the United States 1

Hib (Haemophilus influenzae type b Conjugate Vaccine)

• The second dose of Hib conjugate vaccine should be given at 4 months 1
• Important caveat: If PRP-OMP (PedvaxHIB or ComVax) is used at 2 and 4 months, a dose at 6 months is not required 1
• If other Hib conjugate types (HbOC or PRP-T) are used, three primary doses at 2,4, and 6 months are needed 3

Pneumococcal Conjugate Vaccine (PCV)

• The second dose of PCV should be administered at 4 months of age 4, 2
• This is part of a 4-dose series given at 2,4,6, and 12-15 months 4

Rotavirus Vaccine

• The second dose of rotavirus vaccine is due at 4 months 1, 2
• Critical timing consideration: The rotavirus series must be completed by 8 months of age, and vaccination should not be initiated after 14 weeks 6 days of age 1
• If Rotarix is used (2-dose series), the dose at 6 months is not needed; if RotaTeq is used (3-dose series), a third dose at 6 months is required 1

Hepatitis B Vaccine

• If the infant has not yet received the second dose of hepatitis B vaccine (which can be given between 1-2 months), it should be administered at the 4-month visit 1, 2
• The hepatitis B series consists of 3 doses, with the third dose not given before 6 months of age 1

Combination Vaccines

• DTaP-IPV-Hib-HepB (hexavalent vaccine) is licensed for use at 2,4, and 6 months and can simplify the immunization schedule by reducing the number of injections 1
• When combination vaccines are used, all components count toward completion of each respective vaccine series 3
• Different brands of DTaP-containing combination vaccines can be used interchangeably to complete the series 3

Concomitant Administration

• All vaccines recommended at 4 months can be safely administered during the same visit at different injection sites 4, 5
• Studies demonstrate that concomitant administration does not affect immunogenicity or safety profiles 4, 6

Common Pitfalls to Avoid

• Do not delay vaccination if the original vaccine brand is unavailable—different brands are interchangeable 3
• Do not restart the vaccine series if there are interruptions; simply continue with the next dose 3
• Ensure proper minimum intervals: The second dose must be given at least 4 weeks after the first dose 1, 3
• Monitor for fever: Higher rates of fever (47.1%-47.4%) have been observed with hexavalent vaccines compared to pentavalent vaccines, though fever-related medical events remain similar 1