Rates of infection by the 2009 H1N1 influenza virus may have peaked in late October: Quest Diagnostics

Rates of infection by the 2009 H1N1 influenza virus may have peaked in late October, but the pandemic flu virus continues to be a potential source of illness in all age groups, including the elderly, according to a new report by Quest Diagnostics Incorporated (NYSE: DGX), the world's leading provider of diagnostic testing, information and services.

In its most recent Quest Diagnostics Health Trends(TM) Report "Testing for H1N1 in America," Quest Diagnostics analyzed results of more than 142,000 de-identified patient specimens tested for the 2009 H1N1 influenza virus in the U.S. between May 11, 2009, when the company introduced its first test for detecting the pandemic virus to physicians, and November 10, 2009. Quest Diagnostics is the only company in the U.S. that both performs 2009 H1N1 laboratory testing and, through its Focus Diagnostics business, provides two commercial 2009 H1N1 flu virus test kits authorized by the FDA for emergency use by complex molecular labs.

Key findings from the report:

• In the weeks following October 27, test demand for the virus has declined after several weeks of strong growth.
• About 99 percent of positive influenza A specimens tested were positive for 2009 H1N1 influenza.
• The number of specimens that tested positive for 2009 H1N1 influenza dropped in all age groups since late October, with the exception of those 65 years of age and older. In this age group, rates of positivity have tripled since late August, and are now at about 14 percent.
• Rates of positive test results for the pandemic have declined in recent weeks in most regions, with the exception of the Northeast, where rates have more than doubled during the two weeks ending November 10 compared to approximately the last two weeks of October.

"Our data provides encouraging signs that the 2009 H1N1 pandemic virus isn't spreading as aggressively now as it did in September and most of October. This decline may be due to several factors, including infection of millions of Americans with this influenza virus and the impact of H1N1 vaccinations, which may have reduced the number of people susceptible to infection, and changes in physician test-ordering practices," said Jay M. Lieberman, M.D., medical director, infectious diseases, Quest Diagnostics. "Nonetheless, our data also clearly indicates that the 2009 H1N1 virus continues to be the predominant influenza strain in the U.S. The bottom line is that the 2009 H1N1 flu pandemic in America is far from over."