CDC and WHO recommend that sample
panels of influenza A/H2N2 be destroyed
CDC, HHS, and the World Health Organization are
working with the College of American Pathologists (CAP) and other providers of
proficiency testing panels (see below) to ensure that influenza A/H2N2 samples
sent to U.S. laboratories and laboratories in 17 other countries are destroyed
immediately. Information sent with these proficiency testing panels did not
indicate that influenza A/H2N2 samples were included. The A/H2N2 samples sent
out are similar to the A/H2N2 viruses that circulated in humans in 1957 at the
beginning of the Asian influenza pandemic. Influenza A/H2N2 viruses continued
to circulate widely in the human population until they disappeared upon the
introduction of influenza A/H3N2 viruses during the 1968 Hong Kong influenza
pandemic. Therefore, persons born after 1968 have no or only limited immunity
against A/H2N2 strains. To date, no influenza A/H2N2 human cases among
laboratory workers have been associated with distribution or handling of these
proficiency testing panels. However, because of the potential risk associated
with this particular strain, laboratories have been advised to immediately
autoclave or incinerate and treat as potentially infectious and hazardous all
materials retained or derived from these panels.
CAP, the American Association of Bioanalysts, the American
College of Family Physicians and the American College of Physician Services all
sent proficiency testing surveys containing one or more samples of A/H2N2 to
approximately 6,500 labs in the United States. Proficiency testing panels
containing A/H2N2 samples were also sent to laboratories in Belgium, Bermuda,
Brazil, Canada, Chile, France, Germany, Hong Kong, Israel, Italy, Japan,
Lebanon, Mexico, Saudi Arabia, Singapore, South Korea and Taiwan. The World
Health Organization has informed the Ministries of Health in these countries.
Although there is low risk of infection of laboratory
workers who use proper biosafety precautions, and historic data suggest that it
is unlikely that a laboratory worker will have been infected, destruction of
the samples is strongly recommended. Instructions for appropriate destruction
of the A/H2N2 samples were distributed to the laboratories that received A/H2N2
samples.
CDC remains in close communication with WHO, as well as the
College of American Pathologists and other providers of proficiency testing
panels, about the identification and destruction of the H2N2 panels of concern
and will provide additional information as it becomes available.