The influenza season is soon to be over for this year; however, it has been a long and relatively severe one. Perhaps we can learn a lesson from remembering the 19818 flu pandemic. We had no flu vaccine 100 years ago and as more of us do not get the flu shot during a given year, we could approach that level of morbidity and mortality again – a frightening thought. Many people do not get a flu shot these days and therefore indirectly and unknowingly contribute to this severity.
Part of the problem involves a phenomenon called “herd immunity” and we’re not talking cattle here. It implies that if enough people in a population are immunized against certain diseases, then it is very difficult for those diseases to spread. For example, when about 90 percent of the population is vaccinated, the spread of the disease is stopped. In other words, the 10% of the herd is susceptible but there are so many vaccinated people there is less chance that the 10% would be exposed to the disease.
Another example: In 2003, measles outbreaks became more prevalent in the UK. Part of the reason was that many parents were not having their children vaccinated with the MMR vaccine due to its alleged association with autism. Later studies failed to support this association; however due to a lack of herd immunity the increased outbreaks occurred.
So next fall when the next flu vaccine (although not perfect) becomes available, think about a hundred years ago and get a flu shot for the “herd”.