May 29, 2008 (CIDRAP News) – With summer temperatures settling in across the United States, health authorities are conceding that the novel H1N1 flu virus may continue circulating through the summer, rather than quieting down as seasonal flu strains do.

That could pose major challenges for surveillance of the new flu’s spread, because some important disease indicators, such as school absenteeism, cannot be used during the summer. It will also tug research on the strain toward an aspect of flu that is not well understood despite years of inquiry: why influenza is a seasonal infection.

The Centers for Disease Control and Prevention (CDC) signaled yesterday that it does not expect the novel virus to mimic seasonal flu’s usual summer hiatus.