Wednesday, April 29, 2009


Since the outbreak of the swine flu on the American continent, we have been wondering about typical flu mortality in Hawaii. Hawaii doesn't have a flu season; year round visitors from Asia, Europe, the Americas, and other Pacific Islands results in year-round influenza cases in Hawaii due to a plethora of viruses.

We wondered if Hawaii’s tropical climate resulted in more deaths due to influenza as compared to other States. After all, bacteria certainly thrives in Hawaii’s sultry heat. But the chart above, using the latest CDC mortality rates by State from 2005, shows Hawaii’s rate of death by influenza and pneumonia is low compared to the overall rate in the US and majority of the other individual States.

Hawaii reported 241 deaths by flu and pneumonia in 2005, 15% of the overall deaths for that year (the rates are age-adjusted rates per 100,000 U.S. standard population). This was less than the overall US rate of 20.3% and only Alaska (12.3%), Florida (11.8%), Minnesota (14.5%), Oregon (14.5%), Washington (14.5%), and Vermont (13.7%) had lower age-adjusted rates of mortality. It is interesting that most of these States have relatively humid weather.

We were surprised to discover
numerous studies showing that viruses do not flourish if the humidity is over 50% and those that do survive are weakened from the heat and less likely to cause death (at least in laboratory animals). The hot and humid weather that is the norm in most of Hawaii disrupts a virus’s ability to survive and transmit.

Hawaii had a different experience during the great flu pandemic of 1918 than the Southern and Northern Hemispheres. The first flu case came in the Spring, like most of the rest of the world, but the flu persisted in Hawaii during the summer and through to the Fall. The rest of the world saw the flu disappear in the summer and reemerge with fury in the Fall. Hawaii had a low death rate from that flu epidemic compared to the rest of the world.

Each year in the U.S., an average of 36,000 people die and more than 200,000 are hospitalized from serious flu complications. Ninety percent of flu deaths and more than half of hospitalizations from the flu occur in people age 65 and older. In Hawaii,
115 of the 241 deaths in 2005 were 85 or more years of age.

As we watch the growing worldwide concern and rising numbers of deaths from this new strain of influenza, swine flu, we take comfort in knowing that Hilo's rainy nights and warm humid days may be our best defense against the threat.


Anonymous said...

the flu also is worse in the winter because people lock up their homes and offices and stay inside more where they are more likely to get and spread the virus.

Anonymous said...

Just found this nice site with flu data.
Some useful stuff there.

I don’t think that thsi thing will go pandemic! It will be gone within a month.

Anonymous said...

The Oregon and Washington stats are misleading - a lower % of people die of flu because the sinus infections kill them off before the flu can get them. ;)