What routine vaccinations are indicated for a clinically well 6‑week‑old infant?

Routine Vaccinations for a 6-Week-Old Infant

A clinically well 6-week-old infant should receive the first dose of rotavirus vaccine, DTaP, Hib, PCV13, IPV, and the second dose of hepatitis B vaccine at this visit, as all these vaccines reach their minimum eligible age of 6 weeks. 1, 2

Core Vaccine Schedule at 6 Weeks

At exactly 6 weeks of chronological age, the following vaccines are indicated:

• Rotavirus vaccine (first dose) – This is the most time-sensitive vaccine at this visit, as it must be initiated between 6 and 14 weeks 6 days of age; delaying beyond this narrow window is contraindicated due to increased intussusception risk. 3, 1

• DTaP (first dose) – Protects against diphtheria, tetanus, and pertussis, with the minimum age of 6 weeks making this the earliest safe administration point. 1, 4

• Haemophilus influenzae type b/Hib (first dose) – Critical protection during the period of waning maternal antibodies when infants are most vulnerable to invasive Hib disease. 1, 4

• Pneumococcal conjugate vaccine/PCV13 (first dose) – Provides protection against invasive pneumococcal disease, which carries significant morbidity and mortality in young infants. 1, 4

• Inactivated poliovirus vaccine/IPV (first dose) – Minimum age of 6 weeks allows initiation of the polio series at this visit. 1, 4

• Hepatitis B vaccine (second dose) – If the birth dose was administered, the second dose is due at a minimum of 4 weeks after the first dose, making 6 weeks an appropriate timing. 1, 4

Critical Timing Rationale

The 6-week visit represents the earliest opportunity to begin the primary vaccine series because:

• Maternal antibodies are declining rapidly at this age, leaving infants increasingly vulnerable to life-threatening infections like pertussis, Hib meningitis, and pneumococcal sepsis. 1

• The infant immune system is sufficiently mature at 6 weeks to mount protective responses to these antigens without excessive maternal antibody interference. 1

• Rotavirus vaccination has an absolute upper limit for initiation at 14 weeks 6 days, making the 6-week visit essential to avoid missing this narrow window entirely. 3, 2

Simultaneous Administration

• All indicated vaccines should be administered at the same visit to maximize protection during this high-risk period and improve series completion rates. 3, 1

• Simultaneous administration of multiple vaccines is safe, well-tolerated, and does not increase adverse events or diminish immune responses. 3

Common Pitfalls to Avoid

• Do not delay vaccination for minor illnesses such as mild upper respiratory infections, low-grade fever, or diarrhea—these are not contraindications. 5

• Do not use corrected gestational age for preterm infants—all vaccines should be given at chronological age of 6 weeks regardless of prematurity, with the sole exception being hepatitis B birth dose in infants <2,000g born to HBsAg-negative mothers. 1, 6

• Do not defer rotavirus vaccine thinking you can "catch up later"—missing the 6-14 week window means the infant cannot receive this vaccine at all. 3

• Do not reduce vaccine doses for low birth weight or preterm infants—full doses are required for all infants regardless of size. 1, 6

Special Considerations for Preterm Infants

• Medically stable preterm infants should receive all vaccines at 6 weeks chronological age using the same schedule and full doses as term infants. 1, 6, 7

• Very preterm infants (<32 weeks gestation) may experience apnea or bradycardia within 48 hours post-vaccination; consider cardiorespiratory monitoring for the first vaccine doses in hospitalized infants. 1, 7

• The only exception to chronological age scheduling is hepatitis B birth dose for infants <2,000g born to HBsAg-negative mothers, which should be deferred until 1 month of age or hospital discharge. 1

Contraindications

• Severe allergic reaction to any vaccine component or previous dose contraindicates that specific vaccine. 3

• Severe combined immunodeficiency (SCID) contraindicates rotavirus and other live vaccines. 1

• Encephalopathy within 7 days of a previous pertussis-containing vaccine contraindicates further DTaP. 1