Is this an epidemic?

It is in this above background that the current ‘swine flu’ outbreak in India needs to be viewed. Clearly there is a major outbreak of influenza in India that is currently affecting many parts of the country. As is to be expected, local conditions like climatic and health system related are determining the spread in different states, explaining why some states are more affected than others. In epidemiological terms it is not clear whether this can be termed as an epidemic. To term a disease outbreak as an epidemic it has to be shown that the prevalence of the disease is significantly higher than in similar periods, earlier. As we have noted earlier, seasonal influenza affects all countries, including India, every year. What we are seeing today is that the H1N1 virus is now a seasonal strain and that hence it is not surprising that influenza patients are testing positive to the H1N1 strain.

The problem of terming this an epidemic is critically related to the fact that we do not have reliable population wide data regarding disease prevalence and morbidity and mortality related to different diseases. Because we do not have the data we do not know if infection rates and deaths are significantly higher than in ‘normal’ seasons. It could just be a one season spike in cases, as is to be expected because the immune protection of the 2009 pandemic has receded. Thus for example, if we only go by the number of reported deaths, then it would not be seen as an epidemic in the US – where an average of 36,000 deaths is related to influenza every year. In India, we simply don’t know the average number of deaths caused by influenza.

However, because we do not have population wide disease surveillance data, many questions remain unanswered. We don’t know if the majority of the flu cases are being caused by the H1N1 virus. We don’t know if the number of cases is significantly higher this season, nor whether a relatively higher percentage of the infected run the risk of severe symptoms. We don’t know if the H1N1 strain has mutated and become more virulent. Because we don’t know, even people at the highest levels of governance are content to speculate and spread disinformation. Recently the chief minister of Bengal is believed to have stated that the government would control the swine population in the state to counter the outbreak. Such statements are an example of the ignorance about public health that pervades the highest levels of the administration and government.