Vaccine efficacy – Rotavirus vaccine RotaTeq (RV5)
A new analysis, published online by The Journal of Infectious Diseases, takes a look at acute gastroenteritis hospitalization (AGE) rates among US children under 5 years old, before and after the introduction of the first Rotavirus vaccine, RotaTeq (RV5) in early 2006. The objective of this analysis was to see if there was any change in gastroenteritis hospitalization rates after the vaccine was licensed for use among infants in the United States. The study I am referring to is this one:
Aaron T. Curns, Claudia A. Steiner, Marguerite Barrett, Katherine Hunter, Emily Wilson, and Umesh D. Parashar
The Journal of Infectious Diseases 2010;201:1617–1624 © 2010 by the Infectious Diseases Society of America. All rights reserved.
Why did they look at gastroenteritis hospitalization rates? Because that disease, commonly referred to as the “stomach flu“, is a viral infection, and rotavirus is the leading cause of severe gastroenteritis in children, credited with causing about 50% of acute gastroenteritis hospitalizations during January-June amoung U.S. children. Logically, if rotavirus causes it, and if an effective vaccine is introduced, we ought to observe statistically significant decreases in gastroenteritis hospitalization rates, and this is what this analysis was set up to do.
Study Summary -The authors gathered approximately 100% complete AGE hospitalization rates for children under 5 years of age, from 18 states, accounting for 49% of the U.S. under 5 children population. Median AGE hospitalization rates from the pre-vaccine years of 2000-2006 were compared with median AGE hospitalization rates from 2007, the first year after the vaccine, and 2008.
Results – Overall AGE hospitalization rates went down by 16% in 2007 and decreased by 45% in 2008. By age group, the reductions line up like this:
- 0-2 months – 28%
- 3-5 months – 42%
- 6-23 months – 50%
- 24-59 months – 45%
Prior to RV5 introduction, children in the 6-11 month age group had the highest hospitalization rates; after vaccine introduction children in the 0-2 month age group had the highest hospitalization rates, and showed the lowest decreases. Given that the first dose of the vaccine is given at 2 months of age, this result is to be expected.