No, the first dose of rotavirus vaccine cannot be given at 5 months old
The first dose of rotavirus vaccine must be administered between 6 weeks and 14 weeks, 6 days of age (approximately 3.5 months maximum), and vaccination should not be initiated for infants aged 15 weeks or older. 1
Critical Age Restrictions
The maximum age cutoff for initiating rotavirus vaccination exists for important safety reasons:
- Maximum age for dose 1: 14 weeks, 6 days (approximately 3.5 months) 1
- Minimum age for dose 1: 6 weeks 1
- At 5 months old (approximately 20-22 weeks), the infant has exceeded the maximum age window for the first dose by several weeks 1
Why This Restriction Exists
The age restriction is based on the lack of safety and efficacy data for initiating vaccination in older infants, particularly regarding the theoretical risk of intussusception:
- The previous rotavirus vaccine (RotaShield) was withdrawn in 1999 due to association with intussusception, with greatest risk after the first dose 2
- Current vaccines (RotaTeq and Rotarix) were studied only in infants who received the first dose by 14 weeks, 6 days of age 1
- Insufficient data exists on the safety of dose 1 in infants aged 15 weeks or older 1
What to Do Instead
For a 5-month-old infant who has not received any rotavirus vaccine:
- Do not initiate the rotavirus vaccine series - the infant has aged out of eligibility 1
- The opportunity for rotavirus vaccination has passed for this child 1
- Focus on ensuring all other age-appropriate vaccines are up to date 1
Important Caveat
If dose 1 was inadvertently given at 15 weeks or older, the series should still be completed according to schedule by 8 months of age, as the timing of dose 1 should not affect safety of subsequent doses 1. However, this does not apply to your scenario where no doses have been given yet.