H1N1 epidemic was more dangerous in Mexico, study reveals

The 2009 H1N1 epidemic appears to have been more dangerous than most seasonal flu pandemics, as well as more lethal, in Mexico, than in other countries.

Researchers from Mexico and the United States recently analyzed the mortality rates of the epidemic in that country as well as the years of life lost, a measure designed to elucidate the impact of the epidemic through the integration of age effects and the public health impact, according to CIDRAP News.

Because of differences in diagnostic testing and disease reporting, it remains difficult to determine the impact of the 2009 H1N1 epidemic, especially its morbidity and mortality rate.

The new study, which was recently published in the journal Clinical Infectious Diseases, estimates the mortality and YLL rates in Mexico using monthly statistics on age and cause-specific death rates from 2000 to 2010, as well as population-based influenza surveillance.

The researchers discovered that the virus was associated with the deaths of 11 out of every 100,000 in Mexico, in comparison with the U.S. pandemic rate of four deaths per 100,000 people, CIDRAP News reports. The YLL was 445,000 in Mexico for the same period.

Dr. Lone Simonsen, an epidemiologist with the George Washington University and a co-author of the study, said it remains unclear as to why the mortality rate would be so much higher in Mexico.

One theory is that the virus that hit Mexico early was somehow different than what circulated later, according to CIDRAP News. It is also possible that higher rates of pneumococcal bacteria could have led to more deaths.

Simonsen said the findings provide interesting angles for further research.