Impressive data on likely RotaTeq impact; Rotarix ACIP recommendation added

A good amount of news about rotavirus vaccination in the U.S. came out of Atlanta yesterday. First, a CDC report issued as an MMWR Early Release detailed encouraging data on trends regarding the impact of rotavirus. Titled "Delayed onset and diminished magnitude of rotavirus activity -- United States, November 2007-May 2008," the report examines data from clinical laboratories as to the frequency and timing of confirmed rotavirus samples during the rotavirus season currently underway.

In addition to seeing a delay of 2-4 months in the start of this year's rotavirus season, the report states that the number of positive tests for rotavirus was "substantially lower during the 2007-08 rotavirus season than during any of the prevaccine seasons." These trends coincide with increasing use of RotaTeq, Merck's rotavirus vaccine, approved in 2006. (Despite being the most likely explanation, both the report and an accompanying CDC press release acknowledge that the role of the vaccine cannot be stated definitively from these data alone.)

If these changes are, in fact, attributable to RotaTeq, there are also early signs that the benefit of vaccination may extend beyond those vaccinated to the community-at-large. The MMWR piece explains:

"Because the changes in rotavirus activity appear more pronounced than might be attributed to direct protective effects of vaccination alone, the results of this analysis suggest that vaccination of a proportion of the population might offer indirect benefits to unvaccinated children (i.e., herd immunity) by reducing transmission of rotavirus in the community. "

Needless to say, more data will be needed to see whether this positive trend continues in future years, as well as whether the declines in positive tests for rotavirus correspond with decreases in rotavirus-induced hospitalizations and deaths as vaccination programs proceed.

Here's coverage from the Los Angeles Times and the Washington Post, and a press release by Merck touting the positive news.

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In other rotavirus vaccine news, GSK's Rotarix, approved by FDA in April (as we noted previously), was added yesterday by the Advisory Committee on Immunization Practices to its universal recommendation for infants. No preference was stated between the two vaccines by ACIP. Here's a story on the recommendation (technically not official until published in MMWR) by the Associated Press.

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Unrelated to rotavirus, the ACIP also voted to add recommendations for two combination vaccines as options for parents and physicians: Sanofi Aventis' Pentacel (DTaP, polio, Hib) and GSK's Kinrix (DTap, polio), both of which would reduce the total number of injections needed to complete the recommended vaccination series. This Reuters story has more.