New England Journal of Medicine
Volume 362 — April 29, 2010 — Number 17
http://content.nejm.org/current.shtml

To the Editor: Madhi and colleagues (Jan. 28 issue)1 describe the effectiveness of a live, oral rotavirus vaccine against rotavirus gastroenteritis among infants in South Africa and Malawi. The vaccine had 64.1% efficacy against G1 rotavirus strains and 59.7% efficacy against non-G1 strains. However, we need to consider the prevalence of various strains before introducing the vaccine extensively in the community. A study in Bangladesh from 2001 through 2005 showed that the G1P[8] strain was the most prevalent (36.4%), followed by G9P[8] (27.7%), G2P[4] (15.4%), and G12P[6] (3.1%), but in 2005–2006, G2P[4] appeared as the most prevalent strain (43.2%), and G12P[6] increased in prevalence (11.1%).2 The recently licensed Rotarix vaccine includes only P[8] specificity, with less efficacy against heterotypic non-P[8] strains. The study by Kafulafula et al. showed that breast-feeding influences the rate of gastroenteritis in infants during the first year of life,3 although the authors did not report these results. The currently available Rotarix vaccine might provide good coverage against rotavirus strains that are prevalent in wealthier countries, but for developing countries like Malawi, we might need a vaccine containing different rotavirus strains.

Dewan S. Billal, Ph.D.
University of Laval
Quebec, QC, Canada
dsbh2000@yahoo.com