By Jillian Murray
“Influenza… what about HIV? That’s what people are dying from here.”
These are the words I heard in countless conversations while working on an influenza research project in South Africa last summer. Nearly every time I mentioned I was working on a public health research project I was met with a chorus of “ohhh HIV.” After explaining that I was, in fact, researching influenza, the conversation usually shifted to wondering why I would focus on something other than HIV.
I remember leaving some people unconvinced of the importance of studying respiratory diseases. Many had an emotional connection to HIV and recounted stories of people they knew dying of AIDS, but were unable to recall someone who died of influenza. In some populations, this acute awareness of the devastation of the HIV/AIDS epidemic has led to an ideology where an HIV diagnosis is mutually exclusive of other diseases.
Jillian Murray and a colleague in the Soweto township in Johannesburg during interviews for a health survey.
I found it interesting to witness the distinct hierarchy in the perceived importance of certain diseases. Influenza causes annual worldwide epidemics and can be a life-threatening complication of many other diseases, but because many people rank it’s severity slightly above the common cold, it is often assumed to be rather harmless. This is not only true in settings where there are other high priority communicable diseases, but is a common perception in North America as well.
The true burden of influenza is not well described in many developing countries. However, the burden is expected to be higher in developing compared to developed countries because of underlying factors that contribute to greater severity of disease – factors like crowding, low birth-weight, malnutrition and HIV, among others. In contrast to developed countries where the burden is primarily in the elderly population, these socio-economic factors play a role in broadening the demographic that is most at-risk for severe influenza in South Africa.
A better understanding of the burden of influenza is important for pandemic planning and more effective distribution of vaccine supply. While in South Africa, I worked under the supervision of Daniel Feikin, IVAC’s Director of Epidemiology. With the help of researchers at the National Institute of Communicable Diseases, we used a statistical model that adjusted for influenza risk factors between different provinces to estimate the burden of severe influenza at the provincial and national levels.
As it turned out, my work was very much related to HIV, which severely compromises the immune systems of those affected. There is evidence that HIV-positive individuals suffer a much greater mortality rate from influenza than HIV-negative individuals and that the risk for acquiring influenza in HIV-positive individuals is much greater than in HIV-negative individuals. A high prevalence of HIV, such as exists in South Africa, can cause the burden of influenza to be much greater than you would expect in a population with low HIV prevalence. For these reasons, HIV became one of the most influential risk factors for which we controlled in our study.
An important aim of the burden study in South Africa was to guide public health authorities in the country on how their policies regarding influenza vaccination can better meet the needs of their population. The HIV prevalence in South Africa, while varied between provinces, averages 17% in the 15-49 age group. It is crucial for public health officials to understand the disproportionate risk people in this age cohort have of developing severe influenza infections, and to develop policies and programs accordingly.
My conversations about why I was researching influenza were both valuable learning and teaching opportunities for me. The devastating HIV epidemic in South Africa is inextricably linked to increased susceptibility of its population to concomitant infections, such as severe cases of influenza. Therefore, it is important that discussions of HIV and influenza overlap in order to reinforce in the public’s mind the relationship these diseases have with each another. I hope I was able to play a role – however small – in increasing this understanding.
Jillian Murray is a second year Master of Science in Public Health (MSPH) student in the Global Disease Epidemiology and Control program at Johns Hopkins Bloomberg School of Public Health.