December 16, 2010

Signs point toward lighter flu season

Signs point toward lighter flu season

A Vanderbilt researcher's work to examine the impact of H1N1 influenza on children in the Southern hemisphere is shedding light on the sort of flu season we might expect this year in North America.

While working in his native country of Argentina, Fernando Polack, M.D., the Cesar Milstein Professor of Pediatrics, described the impact of H1N1 influenza on children during the H1N1 pandemic in a New England Journal of Medicine study in 2009. This month, in a correspondence in the NEJM, Polack expands on that work and has good news for those of us just entering flu season.

In the correspondence, Polack describes the 2010 flu season for pediatric patients in Argentina as very mild, especially when compared with the same population during the 2009 flu season.

This year there were no pediatric deaths from influenza, fewer than 50 children were hospitalized during peak flu season months, and none due to pandemic H1N1 (May 1 to July 31, 2010). Polack suggests the world-wide vaccination efforts in the wake of H1N1 influenza may have helped.

“The interesting thing is that there were no hospitalizations due to pandemic H1N1 influenza virus this year in the same population that was severely affected in 2009. Mainly a variety of type B cases were seen at area hospitals. There are several possible explanations, but one key factor is that about 95 percent of children under age 5 got an H1N1 vaccine before the 2010 flu season,” Polack said.

The severity of last year's flu season may have helped as well. It is estimated that one in three children was infected with H1N1 during the 2009 epidemic, conferring protection against the virus this year.

Last year was one of the more deadly years for pediatric flu patients. Argentina experienced the third largest number of pediatric deaths from the H1N1 flu across the Americas.

During the H1N1 pandemic, Polack worked with six hospitals in Buenos Aires to collect the data for his initial study. The hospitals serve 1.2 million children in Argentina. After the deadly 2009 season, Polack re-examined hospital admission and nose swab data to confirm the types and severity of flu seen in 2010.

In addition to his role in Vanderbilt's Department of Pediatrics, Polack serves as the director of INFANT Foundation, a research and clinical institute based in Buenos Aires.