Thursday, April 30, 2009

Explaining the H1N1 influenza death rate in Mexico

In a highly unscientific "study", I heard reports question why the suspected death toll for H1N1 is higher in Mexico, but no subsequent answers followed. Naturally, I turned to Google for insight.

In 2006, researchers found that a country's income was the biggest predictor of its death toll in an influenza pandemic. The lack of income per capita in Mexico is evident in the large number of uninsured citizens who accordingly receive minimal federal health care in what amounts to a three-tier health system. This figure of 50 million uninsured out of an estimated population of 110 million amounts to approximately 45%.

According to a 2007 news release from the New Mexico Department of Health, influenza was not systematically monitored in Mexico. While this lack of monitoring may be in part due to lack of resources, it was likely aggravated by the World Bank-led neo-liberal health reform, which failed to prevent a shortage of adequately skilled staff and likely increased the bureaucratic barriers to inter-state cooperation in communicable disease monitoring.

My tentative conclusion is that poverty, insufficient resources, organizational dysfunction, and a lack of political will for influenza surveillance left Mexico in a condition vulnerable to an influenza pandemic.

As a consequence, it's entirely possible that H1N1 has gone undetected for some time and that the apparently high death toll to date (based on suspected rather than confirmed cases) could be more a function of total population infected rather than elevated lethality.

1 comment:

dr.skip said...

According to the Medical Journal, LANCET [368(9554):2211, you are right. "Excess mortality data show that, even in 1918–20, population mortality varied over 30-fold across countries. Per-head income explained a large fraction of this variation in mortality. Extrapolation of 1918–20 mortality rates to the worldwide population of 2004 indicates that an estimated 62 million people (10th–90th percentile range 51 million–81 million) would be killed by a similar influenza pandemic; 96% (95% CI 95–98) of these deaths would occur in the developing world." That means 19 of every 20 deaths will be in poor and developing countries.