What is the recommended vaccination schedule for Rotarix (rotavirus vaccine) in a healthy infant?

Rotarix Vaccination Schedule

Rotarix (RV1) is administered as a 2-dose oral series at 2 and 4 months of age, with strict age restrictions: the first dose must be given between 6 weeks and 14 weeks 6 days of age, and all doses must be completed by 8 months of age. 1, 2

Standard Dosing Schedule

• Dose 1: Administer at 2 months of age (can be given as early as 6 weeks) 1
• Dose 2: Administer at 4 months of age 1
• Minimum interval between doses: 4 weeks 1, 2
• Each dose volume: 1.5 mL administered orally directly into the infant's mouth 2

Critical Age Restrictions

These age limits are absolute and cannot be violated:

• Minimum age for first dose: 6 weeks 1, 2
• Maximum age for first dose: 14 weeks and 6 days (do NOT initiate vaccination at 15 weeks or older) 1, 2, 3
• Maximum age for final dose: 8 months and 0 days 1, 2

The ACIP and AAP emphasize that vaccination should not be initiated for infants aged 15 weeks or older due to insufficient safety data on the first dose in older infants. 1 If an infant reaches 15 weeks without receiving the first dose, they have permanently aged out of eligibility and should not receive the vaccine series. 3

Co-administration with Other Vaccines

Rotarix may be administered simultaneously with all routine infant vaccines without interference: 1, 2

• DTaP (diphtheria, tetanus, acellular pertussis) 1
• Haemophilus influenzae type b (Hib) 1
• Inactivated poliovirus vaccine (IPV) 1
• Hepatitis B vaccine 1
• Pneumococcal conjugate vaccine 1
• Inactivated influenza vaccine (for infants ≥6 months) 1

Special Populations

Preterm Infants

• Use chronological age from birth, not corrected gestational age 2, 4
• Vaccinate on the same schedule as term infants if the infant is clinically stable 1
• May vaccinate at discharge from NICU/nursery if age-eligible and clinically stable 1
• If readmitted within 2 weeks after vaccination, institute contact precautions for 2-3 weeks post-vaccination due to vaccine virus shedding 1

Breastfed Infants

• Follow the identical schedule as non-breastfed infants 1, 2
• No feeding restrictions before or after vaccine administration 1
• Vaccine efficacy is similar in breastfed and non-breastfed infants 1

Previous Rotavirus Infection

• Complete the vaccination series even if the infant had documented rotavirus gastroenteritis, as natural infection provides only partial immunity 1

Minor Acute Illness

• Administer vaccine to infants with mild gastroenteritis or upper respiratory infection, with or without fever 1

Interchangeability with RotaTeq

• Complete the series with the same product (Rotarix) whenever possible 1
• If the previous vaccine product is unknown or unavailable, continue with available product 1
• If any dose was RotaTeq (RV5) or product is unknown, administer a total of 3 doses to complete the series 1
• All doses must still be completed by 8 months of age regardless of product used 1

Common Pitfalls to Avoid

• Do not attempt "catch-up" vaccination for infants who missed the age window—there is no catch-up schedule for rotavirus vaccines 2, 3
• Do not use corrected age for preterm infants—always use chronological age from birth, which may cause some preterm infants to age out before being stable enough to vaccinate 2, 4
• Do not defer vaccination because other routine vaccines are delayed—rotavirus vaccine has strict age cutoffs that cannot be extended 1
• Do not start the series at 15 weeks or older—the infant has permanently aged out of eligibility 2, 3

Clinical Rationale

The strict age restrictions exist because Rotarix was studied only in infants who received the first dose by 14 weeks 6 days of age, with demonstrated efficacy of 85-96% against moderate-to-severe rotavirus gastroenteritis. 1, 5, 6 The age limits also minimize any theoretical risk of intussusception, which was associated with the previous rotavirus vaccine (RotaShield) when given to older infants. 5, 7