Infection from pandemic influenza viruses often occurs in waves of activity. Since peaking in late October 2009, H1N1 testing and positivity rates have both declined, indicating that a third wave has not occurred. The Quest Diagnostics investigators believe the declines in testing and positivity rates may be due primarily to lower rates of infection from millions of Americans having already been infected with H1N1 and millions more receiving the H1N1 vaccine, which have reduced the number of people susceptible to infection.  In addition, changes in physician test-ordering practices may influence testing patterns.

However, the Quest Diagnostics Health Trends?„? Report also shows that H1N1 has not disappeared, and that the rate of positive H1N1 tests in the south was higher than the rate in the rest of the country in recent weeks.  The most recent data for the four weeks ending April 15, 2010, shows that about 26 percent of patients in all age groups tested in the southeast and 22 percent in the central south were positive for H1N1, compared to 6 percent for the remainder of the U.S. The southeast region includes Alabama, Florida, Georgia, Kentucky, Mississippi, North and South Carolina and Tennessee. The central south region includes Arkansas, Louisiana, New Mexico, Oklahoma and Texas.

The Quest Diagnostics Health Trends Report is based on an analysis of more than 195,000 H1N1 de-identified laboratory tests performed by the company nationally since it launched its first H1N1 test in May 2009. It is believed to be the largest analysis of H1N1 testing data in the U.S. by a private organization. The CDC identified H1N1 as a novel influenza strain in April 2009.

SOURCE Quest Diagnostics Incorporated