The science of disease outbreaks is not an exact science. Although it seems as if the pandemic of H1N1 is waning, the WHO warns Tuesday that it is too early to determine if H1N1 is over. The WHO emergency committee of 15 experts states that the swine flu may reemerge, writes Reuters. With nearly 16,000 people dead from the deadly virus and the spread of swine flu to 212 countries and overseas territories, the subject of the swine flu weighs heavily in many peoples’ minds.
The swine flu is decreasing in most of the northern hemisphere. However, the WHO states that there are recent reported increases in West Africa. Do not get too comfortable yet, because the transmission of influenza often waxes and wanes. The Washington Post writes that pandemics are often unpredictable and will reemerge in unpredictable waves. These waves are dependent on certain factors. These include human behavior, atmospheric conditions, and competition from other microbes, even other strains of influenza. These factors are what make the predictability of new waves so uncertain.
Anne M. Schuchat, leader of the government’s response to H1N1 at the Centers for Disease Control told the Washington Post, “We are not at all out of the woods because the virus continues to circulate, but the chances of a very large additional wave are very hard to predict.” Even biologists who specialize in disease outbreaks state that as for the question of why the H1N1 has retreated since peaking in October 2009 there is no answer.
However, scientists do study how other similar viruses have waxed and waned, and this has given them a few clues. The Spanish flu of 1918 had four waves over the span of two years. These waves occurred at significantly different times. In 1957, the Asian flu, similar to the H1N1 strain, peaked in the late spring and fall. A third peak occurred in the late winter of 1958. Another flu, known as the Hong Kong flu, had its first wave and then it was followed by a second wave more than a year apart. The second wave infected almost as many people as the first wave.
Winter conditions are prime breading grounds for microbes like H1N1. Cool temperatures, low humidity and crowded living conditions are the perfect atmosphere for H1N1 to jump from person to person. Yet, it waned in October. Walter R. Dowdle, an epidemiologist at the Task Force for Global Health in Decatur, Georgia explains to the Washington Post, “ It runs through a community and moves on.”
The WHO has also recommended that the H1N1 strain be included in seasonal flu vaccinations. The WHO also plans to have a press conference on Wednesday to announce the results of their assessment. The expert committee that advised the premature assessment that H1N1 has peaked awaits the final decision to be taken by the WHO Secretary General Margaret Chan.