DOI: 10.1097/INF.0b013e318278bb4e
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PMID: 23838663
Issn Print: 0891-3668
Publication Date: 2013/05/01
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Excerpt
Velásquez and colleagues1 show in a large Mexican cohort study that there is a small but finite risk of intussusception (IS) associated with the first dose of human rotavirus vaccine (Rotarix; GlaxoSmithKline Biologicals, Rixensart, Belgium). The number of additional cases of IS attributable to Rotarix vaccination was estimated at approximately 2 per 100,000 infants vaccinated, which is somewhat less than what was estimated for RotaShield (Wyeth, New York, NY) vaccine before its withdrawal. A study from Australia also identified a risk of similar magnitude after the first dose of both Rotarix and RotaTeq (Merck, Whitehouse Station, NJ) vaccines.2 While, unlike Mexico, the risk of IS after Rotarix could not be detected in Brazil,1 and a recent report from the United States found no increased risk for IS after RotaTeq,3 it would seem that there is no smoke without the fire. A low risk of IS is associated with the administration of the first dose of both currently licensed live oral rotavirus vaccines.
Velázquez and colleagues argue that despite the small risk of IS the risk–benefit ratio remains very much in favor of universal rotavirus vaccination program because a considerable number of rotavirus-associated deaths are prevented by the vaccine.1 This is certainly true for Mexico and many other countries, but is not sufficient to convince some developed countries with little or no mortality from rotavirus that have not yet introduced a rotavirus vaccination program and view the risk of IS as a potential concern. Rather, the critical question is what can be done to reduce the risk of rotavirus vaccine–associated risk of IS, and an obvious issue is the age at the time of administration of the first dose of vaccine.
The background for the importance of age lies with the RotaShield experience. According to Simonsen and colleagues, there were no cases of IS in infants vaccinated between 30 and 59 days of age (denominator 69.123), 9 cases in infants vaccinated between 60 and 89 days of age (denominator 197.144), but a much higher number and 3–4 times higher rate of cases among infants who participated in the catch-up program and received their first dose of RotaShield vaccine between ages of 90 and 159 days.4 A plausible assumption is that the lower risk of IS associated with the current live oral rotavirus vaccines would follow a similar pattern for age. In fact, a recent report from Germany has found just that an increased risk of IS was observed in infants who received the first dose of rotavirus vaccine, either RotaTeq or Rotarix, between ages 90–179 days, but not in infants less than 89 days of age at the time of vaccine administration.5
Velázquez and colleagues mention the age issue only in passing, and note that an exploratory analysis showed no increased risk of IS in infants who received the first dose after 14 weeks of age as compared with those at 14 weeks or less. They also mention that only 18.2% of IS cases were among infants who received the first dose after the recommended limit of 16 weeks of age,4 but do not report what percentage of all children received the first dose of Rotarix after the age of 16 weeks.
A further question is where this “recommended” upper age limit of 16 weeks comes from. In the prelicensure trials of Rotarix (and RotaTeq), the first dose of vaccine was administered strictly between ages 6 and 12 weeks. This age range is also the still existing recommendation in the ESPID/ESPGHAN Evidence-based Recommendations for Rotavirus Vaccination in Europe.
