Is intussusception a side effect of the rotavirus vaccine?

Is Intussusception a Side Effect of the Rotavirus Vaccine?

Yes, intussusception is a recognized but rare side effect of rotavirus vaccines, though the risk varies significantly between vaccine types and is substantially lower than with the withdrawn RotaShield vaccine.

Historical Context: The RotaShield Precedent

The first licensed rotavirus vaccine, RRV-TV (RotaShield), was withdrawn from the U.S. market in 1999 due to a clear association with intussusception 1. This vaccine carried:

• A >20-fold increased risk within 3-14 days after the first dose 1, 2
• An approximately 5-fold increased risk after the second dose 1
• An overall risk of approximately 1 case per 10,000 vaccine recipients 1, 3
• Age-dependent risk, with higher rates in infants vaccinated after 60 days of age 1, 2

Current Vaccines: RotaTeq (RV5) and Rotarix (RV1)

RotaTeq (Pentavalent Vaccine)

RotaTeq demonstrates no significant increased risk of intussusception in most surveillance data 1. Key findings include:

• Prelicensure trial of 70,000 infants showed no evidence of association 1
• Post-licensure VAERS surveillance through March 2008 found cases did not exceed expected background rates 1
• VSD monitoring of >200,000 doses found no increased risk within 30 days of any dose 1
• If any risk exists, it is estimated at no greater than 1 in 25,000-50,000 first doses 1
• One study of 1,301,810 doses found a nonsignificant relative risk of 1.1 4

Rotarix (Monovalent Vaccine)

Rotarix shows a small but statistically significant increased risk of intussusception 5. The most recent and highest quality evidence demonstrates:

• Relative risk of 8.4 for intussusception within 7 days after either dose compared to historical background rates 5
• Relative risk of 9.4 (95% CI: 1.4-103.8) when directly compared to RotaTeq 5
• Attributable risk of 5.3 cases per 100,000 infants vaccinated after two doses 5
• Study included 207,955 doses with 6 observed cases versus 0.72 expected 5

Clinical Implications and Risk-Benefit Considerations

Timing of Risk

The highest risk period is within the first 7 days after vaccination, particularly after the first dose 5, 3. A relative increase in reports during the first week after dose 1 has been noted, though whether this represents true increased risk or reporting bias remains unclear 1.

Contraindications

Infants with a history of intussusception should have risks and benefits carefully weighed before vaccination, as they may be at higher risk for repeat episodes 1. Until additional postlicensure data became available, ACIP recommended careful consideration in this population 1.

Age Considerations

Evidence from the RotaShield experience suggests vaccination should be initiated before 13 weeks of age to minimize potential age-dependent risk 1. The risk may be higher in infants vaccinated after 60 days of age 2.

Risk-Benefit Balance

The benefits of rotavirus vaccination substantially outweigh the small risk of intussusception 6. Consider that:

• Rotavirus causes an estimated 440,000 deaths annually in children under 5 years worldwide 3
• Large prelicensure trials showed no increased risk for both vaccines 6, 7
• The attributable risk, even for Rotarix, is approximately 5 per 100,000 vaccinated 5
• Current vaccines prevent severe, life-threatening rotavirus gastroenteritis 6

Common Pitfalls to Avoid

• Do not confuse background intussusception rates with vaccine-associated risk: Background rates are approximately 1 per 3,300 infants under 1 year 8
• Do not delay vaccination unnecessarily: Delays may make infants ineligible (>13 weeks) or increase age-dependent risk 1
• Do not assume all rotavirus vaccines carry equal risk: Current evidence suggests RotaTeq has lower risk than Rotarix 5