Swine influenza - update 5

29 April 2009

Wednesday 11:45pm

WHO Raises Pandemic Alert to Phase 5 (Pandemic is “Imminent”) as US Cases Increase to 91 in 10 States, and Nine Nations Confirm Cases including New Zealand in the SOUT= HERN Hemisphere. WHO Hosts Meeting on Evolving Clinical and Epidemiological Facts.

The Director-General of the WHO, Dr. Margaret Chan, held= a live press conference from Geneva at ~ 4:15pm (ET) to announce the increase to Pandemic Phase 5 based on community-level outbreaks in Mexico and the USA of the novel influenza A (H1N1) virus (until yesterday referred to as “swine flu”). According to the updated= WHO Pandemic Phase definitions, Phase 5 means that an influenza pandemic (Phase= 6) is “imminent”.

Globally, WHO reported nine (9) nations with lab-confirm= ed infections with this new virus. Only Mexico and the USA have confirmed deaths due to this virus so far. The first death in the USA occurred yesterday in a 23 month-old c= hild from Mexico City who was visiting Texas with famil= y, became ill, and was hospitalized.

Overall, the WHO data are: USA (91 cases with 1 death), Mexico (26 cases with 7 deaths),Canada (13 cases), UK (5 cases), Spain (4 cases), Germany (3 cases), New Zealand (3 cases), Israel= (2 cases), and Austria (1 case).

The WHO today held a special meeting to discuss the specific clinical, epidemiological, and virological data from nations, including the USA and Mexico, that have patients infected with this novel virus. T= he results are expected to be posted on the WHO website soon, hopefully within= 24 hours. This information will be very helpful to clinicians and public health officials as well as other emergency responders and planners around the wor= ld.

In the USA the CDC report= ed an increase from 64 to 91 lab-confirmed cases yesterday, in ten states: New York (51 cases), Texas (16), California (14), Michigan (2), Kansas (2), Massachusetts (2), Ohio (1), Indiana (1), Arizona (1), Neva= da (1).

In a live televised press conference at 3pm (ET) the Secretary of the Department= of Homeland Security (DHS), the overall lead federal official for this outbrea= k, and the newly-confirmed Secretary of Health and Human Services (HHS) stated that anti-influenza medications a= nd other emergency supplies from the US Strategic National Stockpile (SNS) were being distributed across the entire nation.

The US Federal Response Pandemic Stage remained at zero = (0) on the official government website www= .pandemicflu.gov in the morning. It can be anticipated that the question of the applicabilit= y of this US<= /st1:country-region> staging system for this specific pandemic influenza threat will be reviewed= and news of the outcome of the review disseminated soon.

As noted in this newsletter two days ago (Monday, April = 28) the Southern Hemisphere will begin their seasonal influenza season in their winter months of June, July, and August. Thus, if this novel influenza A (H= 1N1) virus becomes established in the Southern Hemisphere now, then it may spread extensively during June-August. To date, this has not occurred. New Zealand is the only natio= n with lab-confirmed cases so far in the Southern Hemisphere.

The threat exists that this novel virus could mutate or recombine with other human influenza, or avian influenza viruses if it spre= ads widely in the human population globally.&n= bsp; Such a recombination event could include the acquisition of an oseltamivir (Tamiflu)-resistant neuraminidase from another human influenza = H1N1 virus.

If the current novel virus becomes dominant in the South= ern Hemisphere from June to August, then it may well become the dominant influe= nza virus in the Northern Hemisphere as well.

Hopefully, this novel influenza A (H1N1) virus will not become resistant to the antiviral drug oseltamivir (Tamilfu), as recently occurred, over the past two years, in both the northern and southern hemisp= here with seasonal human influenza A (H1N1).

Daniel R. Lucey, M, MPH

EROne Institutes, Department of Emergency Medicine<= /o:p>

Was= hington Hospital Center and Medstar Health

Adjunct Professor of Microbiology and Immunology

Geo= rgetown University Medical Center, Washington D.C.= =

Website for this posting: www.BePast.org

e-mail: DRL23@Georgetown.edu