1918 Flu Pandemic Offers Lessons for Today

Although the 1918 flu pandemic occurred over 90 years ago, there are still a number of mysteries concerning this pandemic, mysteries that could have broader implications for how doctors view the flu today.

The effects of the 1918 flu pandemic where widespread and devastating, and the pandemic actually lasted from March 1918 to June 1920. As many as 100 million people may have been killed. The 1918 flu pandemic, like the H1N1 or swine flu pandemic, had a higher mortality rate among the young when compared to traditional seasonal flu epidemics. It was thought that this was due to possibly the 1918 virus "overactivating" the immune system. When a person's immune system comes into contact with a foreign entity, such as a virus, the immune response includes a variety of responses from the immune system that normally protect a person against infection.

While the immune response is normally protective and necessary for survival, a number of diseases may be due, in part, to a chronic immune response or inflammation. Chronic poor dental hygiene, which may lead to chronic gum irritation and inflammation is now believed to lead to an increased incidence of heart attacks.

While the effects of the 1918 flu epidemic were immediate, the children born during the year 1918, presumably to mothers who were infected with the flu, displayed a number of abnormalities not seen in previous or later generations of children. This could very possibly be attributed to the 1918 flu as a third of the world's population was infected with the 1918 flu.

Time magazine ran a recent article on the side effects of the 1918 flu epidemic, which are postulated to have caused and increased incidence of heart attack decades later. Researchers performed a retrospective study by examining health records from 1982 and 1996. They found a spike in the number of heart attacks, by twenty percent, for people born between October 1918 and June 1919.

It is postulated by some researchers that infants born in this time period, when the 1918 flu was most active, were exposed in their mother's womb to the 1918 flu when their mother caught the 1918 flu virus. Other small differences are noted around the same period of time, such that men born in 1919 are 0.05 inches shorter than men born during other years around that time period. Researchers believe that that difference in height was also caused by the 1919 flu.

Researchers have also noted that children born during winter months, when the seasonal flu hits in the United States, that these children have a high rate of schizophrenia than children born during summer months. Schizophrenia has been linked in some studies to an exaggerated immune response, and the seasonal flu could in pregnant women lead to brain inflammation in the fetus. However, it is still largely unknown as to how the seasonal flu increases the risk of developing schizophrenia.

One possible explanation for the higher incidence of heart attacks in infants born to mothers during the 1918 flu pandemic could be that infection in utero, or inside the womb, lead to an inflammatory state which somehow damaged coronary arteries in the infants' hearts. Damage that may be microscopic and not yet identified on studies of the effect of the flu on newborns. And that somehow the scars of this damage lead to an increased risk of heart attacks some sixty years later.

Or it may simply be the extra metabolic stress that the flu adds on to the stress of pregnancy for the pregnant women who caught the 1918 flu.

But can we learn anything from this study of 1918 flu survivors that could be applied today regarding the H1N1, or swine flu epidemic? Perhaps so. As pregnant women are recommended to get both the seasonal flu and H1N1 flu vaccines, these vaccinations which will save the lives of pregnant women, and may also help their children to live longer and healthier lives.

Sources:

Side Effects of 1918 Flu Seen Decades Later
http://www.time.com/time/health/article/0,8599,1929814-2,00.html

1918 Flu Pandemic
http://en.wikipedia.org/wiki/1918_flu_pandemic