EXPERT ADVISORY: The 2009 H1N1 Influenza

By Sathya Achia Abraham

New data about the 2009 H1N1 influenza virus reveals compelling observations about patients hospitalized with the illness – some that could merit further consideration by public health authorities, according to an editorial by two Virginia Commonwealth University physicians published in the Nov. 12 issue of the New England Journal of Medicine.

In the editorial, Richard P. Wenzel, M.D., professor and chair in the Department of Internal Medicine in the VCU School of Medicine, together with Michael B. Edmond, M.D., M.P.H., chair of the Division of Infectious Diseases, noted that ethnic and racial minorities are at high risk for severe illness due to the H1N1 influenza – as are individuals who are obese.

Wenzel and Edmond based their observations on several recent studies - two of which are featured in the current issue of the journal – one U.S study, and the other known as the Australian and New Zealand Intensive Care study. Both studies shed light on the clinical characteristics of patients who have been hospitalized with 2009 strain.

Based on their analysis, Wenzel and Edmond noted that ethnic and racial minorities are at high risk for severe illness due to the H1N1 influenza – as are individuals who are obese. These factors could merit further investigation, however, neither issue has been addressed by public health authorities, according to Wenzel.

“It is time to place obese patients on the high priority list for vaccination with H1N1 vaccine,” he said.

Recent studies also reveal interesting data that the routine seasonal vaccination may have protected some people from the H1N1 virus, according to Wenzel. For example, one case-control study in Mexico described in the editorial suggested a rate of 73 percent protection against the H1N1 virus among patients who received a trivalent seasonal vaccine.

“The Australian/New Zealand study is particularly helpful because influenza season in the Southern Hemisphere occurs opposite that in the Northern Hemisphere, so the findings of that study are helpful in predicting critical care resources that may be needed for our flu season,” said Edmond.

The estimates from Australia and New Zealand suggest much milder outcomes compared to predictions, but Wenzel and Edmond noted that it is imperative to understand that this virus is unpredictable and has been responsible for deaths in children and young adults.

EDITOR’S NOTE: A copy of the editorial is available to reporters in PDF format by email request from mediasupport@nejm.org.