Effectiveness of Lanzhou lamb rotavirus vaccine against hospitalized gastroenteritis: Further analysis and update

Lanzhou Lamb Rotavirus (LLR) vaccine has been licensed for use in China since 2000 but its efficacy and impact on public health have not yet been established. We recently conducted a post-licensure retrospective case-control study and reported an overall vaccine effectiveness (VE) of 73% (95% CI, 61%–82%) for a single dose of LLR vaccine by examining children 2 months to 5 years of age who were hospitalized for treatment of laboratory-confirmed rotavirus gastroenteritis and healthy controls that were 1:1 matched by gender, age and community or village of residence in Guangzhou, China during 2002–2004. In this follow-up analysis, we further assessed VE against hospitalization for rotavirus gastroenteritis among children vaccinated at different ages using a previously described method. The VE of LLR was defined as the proportional reduction in the risk of illness among vaccinated children and was calculated as one minus the matched odds ratio x 100%. Conditional logistic regression was used to calculate the odds ratio. We restricted the analysis to 119 matched pairs with discordant vaccination status where either the rotavirus patient or the matched healthy control was vaccinated at <24 months of age and where both patient and control were born within 60 days of one another. We estimated overall VE at 77% (95% CI, 64%–86%) (Table 1). One dose of LLR vaccine showed a VE of 81% (95% CI, 68%–89%) among children vaccinated at 2 to 11 months of age. Children vaccinated at 2–6 months had a slightly higher VE than those vaccinated at 7–11 months but this difference Effectiveness of Lanzhou lamb rotavirus vaccine against hospitalized gastroenteritis Further analysis and update