A third wave of H1N1 swine flu in the offing?

A third wave of H1N1 swine flu infection surge is possible sometime this winter, alerts a section of flu experts.

If the current trend in H1N1 outbreak follows the pattern of previous pandemics the pandemic virus and its descendents will be among us for some undefined period of time, the warn.

Earlier, a new influenza A virus replaced the previous virus, making it the seasonal flu A strain until the next pandemic occurred.

Influenza B viruses also cause human illness but they don’t trigger pandemics.

Third wave of swine flu or not, it might be more important to get more people immunized.

The current H1N1 pandemic involves two seasonal A viruses, H3N2 and a seasonal H1N1 virus. However, it is too early to say whether the pandemic H1N1 will replace both.

But there is every reason to believe the pandemic H1N1 will cause illness next winter and the winter after that, experts feel.

The activity of flu virus generally start in late November or December and spikes in January or February.

Normally, pandemics do not follow a single pattern. But experts are looking to the most recent pandemics, 1957 and 1968.

According to Dr. Walter Dowdle, who worked on influenza at the U.S. Centers for Disease Control during the former and ran the CDC’s virology division there will be the ongoing transmission of the new virus, but not the sharp spike of activity seen in some places in the spring or early summer and seen in most places this winter.

Between the people who have already had swine flu, have been vaccinated or had pre-existing immunity (seen in some people over age 60), Canada is nearing the point where about half of the population is likely protected against the virus, some people estimate.

But experts like Dr. Allison McGeer would like to believe that there will be a third wave this winter.

“I don’t think the pandemic strain is finished. I think there are too many susceptibles. I think it’s coming back,” stated McGeer, head of infection control at Toronto’s Mount Sinai Hospital.

However, experts alert that notwithsanding the fixation with the third wave, it is more important to get as many people immunized as possible as quickly as possible.

There will be  “a bump” of activity after Christmas, because so many people remain susceptible to the virus, bet some researchers.

Regardless of where the experts come down on the question of a third wave, they say one thing is a safe bet. Whether it’s this winter or next, swine flu will be back.

Meanwhile, WHO has warned that with new H5N1 bird flu cases reported in poultry in Egypt, Indonesia, Thailand and Vietnam, the risk of bird flu and the H1N1 pandemic swine flu virus mixing was heightened.

Source: Helen Branswell, Canadian Press