2nd H1N1 wave may be mild: study

Fears that a possible second wave of the H1N1 in autumn as temperatures drop is more severe and lethal than the current one....

Fears that a possible second wave of the H1N1 in autumn as temperatures drop is more severe and lethal than the current one may be unfounded,says a review in todays issue of the JAMA (Journal of American Medical Association).

David Morens and Jeffrey Taubenberger,infectious disease experts at the US National Institute of Allergy and Infectious Diseases (NIAID),part of the US National Institutes of Health,reviewed past epidemics to conclude that recent flu pandemics exibited no more than one seasonal recurrence before changing into the relatively mild seasonal flu.

The researchers reviewed 14 past flu outbreaks since the 16th century to say that in most of the 20th century epidemics,second waves were either the same or less significant that the first. The researchers say that the current H1N1 spread will ensure that people develop good immunity by the time temperatures drop.

Pandemic history suggests that changes neither in transmissibility nor in pathogenicity are inevitable, the researchers said. The theory stems from the belief that the deadly 1918-19 flu pandemic,which killed 20-40 million people,began with a milder spring wave that got more deadly as the virus spread throughout the summer,picking up lethal mutations.