WHO declares end to H1N1 pandemic

Speaking at a virtual press conference yesterday evening Dr Margaret Chan, the director-general of the World Health Organisation, said the new H1N1 virus has largely run its course and that the world is no longer in phase 6 of influenza pandemic alert. “Put simply,” she said, “the pandemic is over.”

“We are now moving into the post-pandemic period,” she said.

She reiterated that these were the views of the Emergency Committee, which met earlier yesterday.

The Committee based its assessment on the global situation, as well as reports from several countries that are now experiencing influenza.

However, she warned that as we enter the post-pandemic period, this does not mean that the H1N1 virus has gone away.

“Continued vigilance is extremely important, and WHO has issued advice on recommended surveillance, vaccination, and clinical management during the post-pandemic period.

“Based on experience with past pandemics, we expect the H1N1 virus to take on the behaviour of a seasonal influenza virus and continue to circulate for some years to come.

“Globally, the levels and patterns of H1N1 transmission now being seen differ significantly from what was observed during the pandemic. Out-of-season outbreaks are no longer being reported in either the northern or southern hemisphere. Influenza outbreaks, including those primarily caused by the H1N1 virus, show an intensity similar to that seen during seasonal epidemics,” Dr Chan said.

She said that during the pandemic, the H1N1 virus crowded out other influenza viruses to become the dominant virus. This is no longer the case. Many countries are reporting a mix of influenza viruses, again as is typically seen during seasonal epidemics.

“In addition, a small proportion of people infected during the pandemic, including young and healthy people, developed a severe form of primary viral pneumonia that is not typically seen during seasonal epidemics and is especially difficult and demanding to treat. It is not known whether this pattern will change during the post-pandemic period, further emphasizing the need for vigilance.

“Pandemics are unpredictable and prone to deliver surprises. No two pandemics are ever alike. This pandemic has turned out to be much more fortunate than what we feared a little over a year ago. This time around, we have been aided by pure good luck. The virus did not mutate during the pandemic to a more lethal form. Widespread resistance to oseltamivir did not develop. The vaccine proved to be a good match with circulating viruses and showed an excellent safety profile,” she said.

In reply to a question from Reuters about the implications for countries holding remaining stockpiles of oseltamivir vaccine Dr Chan reiterated that the virus was still sensitive to the vaccine. “So they would continue to be useful. And WHO strongly recommends where vaccines are available, high risk groups should be immunized.”

Dr Chan added in response to another question that vaccines that have a shelf life that has expired should be destroyed in keeping with best practice. 

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