Sunday, February 17, 2013

Risk and flu

This video is from a nice website, Risk Bites.

It has been estimated that the Spanish flu that hit during the First World War killed 50 million to 100 million people worldwide. Flu pandemics, of which that was the worst in centuries, occur ever few decades. They occur when a new, highly infectious strain of the flu evolves to which there is little "herd immunity" in the human population. If that strain proves to be very lethal, lots of people die.

It is important that the world maintains epidemiological surveillance systems that would quickly identify the emergence of such a strain in order that public health efforts could be employed in a timely manner. These would include development of an appropriate vaccine and mass immunization campaigns using the vaccine. It is important that we inform the public that flu is more dangerous than immunization, and that they have a public duty to be immunized so that when the next potential pandemic emerges, people will respond.

The regular flu is dangerous. I quote from a January story in Bloomberg News:

The worst U.S. flu season since 2009 intensified last week, killing hundreds more people as the viral epidemic spread to additional states, health officials said. 
About 8.3 percent of all deaths nationwide were due to the flu and pneumonia for the week ended Jan. 12, more than the 7.3 percent level for an epidemic, the Centers for Disease Control and Prevention said today. About 90 percent of those deaths are people older than age 65, who are being hit particularly hard by this year’s flu strain, the Atlanta-based agency said.
Of course, it is important for people at high risk of serious cases of the flu to be immunized, but so too it is important for people who might infect the old or those with impaired immunological systems to be immunized.

Indeed, even if the immunizations are only 60 percent effective, 100 percent coverage can really benefit people. A lot of flu is spread in schools. If all kids and teachers were immunized, there would be a lot of classes in which flu was not spread from student to student. Even if only 60 percent of the kids in the classroom were protected, if one of them is yours, your whole family would be safer. Moreover, the immunizations may reduce the severity of infection even if the person is not completely immune and gets the flu.

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