An early review of the recent influenza A H1N1 scare suggests this virus is more transmissible and lethal than the typical seasonal flu viruses. This is the conclusion of a team of epidemiologists who analyzed the recent outbreak of H1N1 in Mexico. They presented several interesting, but tentative observations:
- Cases which occurred outside of Mexico were most common in those countries that experienced a significant number of travelers from Mexico.
- The risk for children younger than 15 years was higher than for adults (1.52 vs. 1.0). This suggests that although the virus is novel (new), adults may have some protection due to cross-immunity from exposure to strains of the past.
- This virus seems to be transmitted more efficiently from person to person than the typical seasonal flu.
- The estimated fatality rate is 0.4%, slightly more lethal than the seasonal flu varieties, but considerably lower than the 3% death rate of the virus that caused the 1918-1919 flu pandemic.