MANILA, 12 May 2009, 1600 hrs—No new confirmed cases of the influenza A(H1N1) virus were reported in the Western Pacific Region over the past 24 hours. No deaths from influenza A(H1N1) have been reported in the Region.
In total, 17 confirmed cases of influenza A(H1N1) have now been reported in the Western Pacific Region:
- 1 in China, reported 11 May
- 4 in Japan, 3 reported 9 May, 1 reported 10 May
- 1 in Australia, reported 9 May
- 7 in New Zealand, 3 reported 28 April, 1 reported 1 May, 1 reported 4 May, and 2 reported 9 May
- 3 in the Republic of Korea, reported 2 May, 5 May and 7 May
- 1 in Hong Kong (China), reported 1 May.
It has been just two weeks since WHO increased its pandemic level alert to Phase 5, ''a strong signal that a pandemic is imminent''.
Transmission of influenza A(H1N1) among humans has risen sharply since WHO declared Phase 5 on 29 April. The confirmed global case count has increased from just 148 in seven countries when Phase 5 was declared to 4 798 cases in 30 countries as of 12 May. Confirmed cases of the virus jumped by 1 995 over the weekend of 9–10 May alone, and in the same two-day period they increased by 1 358 in the United States of America. While the symptoms exhibited by patients in other countries have been less severe than in Mexico, 53 deaths have been reported globally and hospitalization rates in some of the affected countries are reported to be somewhat higher than would be expected for seasonal influenza.
Although the number of reported cases in the Western Pacific Region remains low, WHO believes strongly that this is no time for complacency. The influenza A(H1N1) virus is expected to continue spreading and infecting more people in more countries. The case for renewed vigilance is stronger now than ever, particularly in the Southern Hemisphere as it moves into its seasonal influenza season.
There remain many unknowns about this virus. Experience with previous pandemics shows they can come in two or three waves, can start mild and become more severe, can affect some countries more than others and can last for as long as two years.
The pandemic of 1957 began with a mild wave followed by a second more severe wave which killed 2 million people. An analysis published on 12 May in the scientific journal Science and facilitated by the WHO Rapid Pandemic Assessment Collaboration, draws parallels between that pandemic and the current outbreak of influenza A(H1N1). It points out that the current fatality rates in Mexico are similar to those of 1957 – but, it should be noted, are nowhere near as high as those seen during the 1918 pandemic.
The analysis in the Science paper, based on early data from Mexico, also appears to indicate that this influenza A(H1N1) outbreak is somewhat different from seasonal influenza outbreaks. Influenza A(H1N1) seems to be more transmissible than seasonal influenza. In addition, younger people appear to be much more likely to become infected than older people - another departure from typical patterns of seasonal flu outbreak.
"It's a virus that almost certainly will cause a global epidemic," study author Neil Ferguson, an epidemiologist at Imperial College London, told the weekly scientific magazine Nature. "But it's not the catastrophic scenario people were fearing for bird flu."
Governments in the Western Pacific Region should take this time to step up preparedness activities. This is an unfolding global event with potential serious health implications particularly for developing nations. WHO believes that based on past pandemics and analysis of the currently available data, up to one third of the world's population could yet get infected by influenza A(H1N1). Past experience of influenza shows that infections which have a mild impact in the developed world can cause much more severe health problems in developing nations.
Global case count
As of 06:00 GMT, 12 May 2009, 30 countries have officially reported 4 789 cases of influenza A(H1N1) infection, with 53 deaths. Mexico has reported 1 626 laboratory confirmed human cases of infection, including 48 deaths.
The United States of America has reported 2 532 laboratory confirmed human cases including three deaths. Canada has reported 284 laboratory confirmed human cases, including one death. Costa Rica has reported eight laboratory-confirmed human cases including one death.
The following countries have reported laboratory confirmed cases with no deaths: Argentina (1), Australia (1), Austria (1), Brazil (6), China (1), Hong Kong (China) (1), Colombia (1), Costa Rica (1), Denmark (1), El Salvador (2), France (12), Germany (11), Guatemala (1), Ireland (1), Israel (7), Italy (6), Japan (4), Netherlands (3), New Zealand (7), Norway (2), Panama (2), Poland (1), Portugal (1), Republic of Korea (3), Spain (88), Sweden (1), Switzerland (1), Thailand (1) and the United Kingdom (34).
WHO is not recommending travel restrictions related to the outbreak of the influenza A(H1N1) virus. Individuals who are ill should delay travel plans and returning travellers who fall ill should seek appropriate medical care. These recommendations are prudent measures which can limit the spread of many communicable diseases, including influenza.
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