A

"Total background and vaccine related cases projected annually per 100,000 infants <12 months of age. "Date of CDC presentation of study, cpp _ F3sldtiv6 risk dExcess cases projected annually for entire U.S. cohort of estimated 4 million infants <12 months of age. ePer 100,000 vaccinees.

"Total background and vaccine related cases projected annually per 100,000 infants <12 months of age. "Date of CDC presentation of study, cpp _ F3sldtiv6 risk dExcess cases projected annually for entire U.S. cohort of estimated 4 million infants <12 months of age. ePer 100,000 vaccinees.

FIG. 2. Number of projected cases of intussusception (attributable risk [AR]) caused by rotavirus vaccine according to CDC in various analyses and times.

53 developed intussusception in a larger never-vaccinated group of children observed over a longer period of time but whose absolute number was not available) (ACIP 1999). It was noted in this expanded cohort study that RRV-TV had an attributable risk of 1 case of intussusception per >12 000 doses (ACIP

1999). In another estimate at this meeting, they also noted that the RRV-TV was causally related with one case of intussusception per 5000 vaccinees or 800 excess cases.

Three months later, in January 2000, CDC reported the attributable risk from the case-control study, to be 1 case of intussusception per 4500 vaccinees (or 22.2 per 100 000 infants, or 888 excess cases) (Fig. 2) (NIH/NVPO Workshop 1/21/

Moreover, on 11 April 2000, at the CDC EIS Conference, the CDC reported that from a further expanded cohort study, which now included 10 MCOs, the risk of developing intussusception after vaccination was 1 case per 12 274 infants—an almost fivefold reduction from a figure presented to the ACIP in October 1999 when the vaccine was withdrawn (Fig. 2). In this further expanded cohort study, six cases of intussusception were detected in 61 371 RRV-TV-vaccinated infants in the first 3 weeks after vaccination (or one case per 20 100 doses of vaccine). The 10 MCOs cohort study provided the most reliable data available up to that time regarding attributable risk because it included the largest number of vaccinated children and, in addition, the rate of intussusception in relation to the absolute number of vaccinees was available rather than only person-year calculations.

We have consistently had a problem with the odds ratios and attributable risk figures presented by CDC. The attributable risk of 1 case per 12 274 (or 8.1 cases/ 100 000) vaccinated infants) (CDC-EIS Conference 4/11/00) is in sharp contrast to the reported relative risk of 1.8 from the case-control study (i.e. 40 excess cases per 100 000) and the odds ratios which had ranged from 13—25 for rotavirus vaccine recipients during the first week after vaccination in the case-control, case-series and cohort studies (Fig. 2) (ACIP 1999). These magnified odds ratios observed during the first week after the first dose received special emphasis and attention by the ACIP and public health community, whereas the overall attributable risk figure of ~ 1:12 000 which has not been available until recently, has not been placed in proper perspective.

0 0

Post a comment