Flu deaths reality check

[link to www.cbc.ca]

under 50%

Flu models versus counts

Getting back to the question of how deadly influenza really is, fate did offer up a chance to check the model predictions when the flu pandemic hit in 2009, and the world faced a new influenza threat called H1N1.

Back then a flu expert told me that the pandemic would be a rare opportunity to check the true death toll from flu, because, for the first time, there was widespread lab testing, a national reporting system, and all eyes were on potential flu-related deaths. The final count: 428 deaths, which is much closer to the seasonal average of around 300 recorded in the vital statistics tables than to the 2,000 to 8,000 deaths estimated for the average flu season by the computer models.

So how did the models rate after a real life test? "The predictive models of 2009 of influenza have actually been a complete failure," respiratory-infection expert Jefferson said.

"Ranges like 2,000 to 4,000 or even 8,000 influenza-related deaths a year are thrown around each flu season, and policy decisions and flu shot campaigns are based on these numbers," Michael Gardam told me. "I think it is important for us to remember that these numbers are estimates and certainly not written in stone. These numbers vary a great deal depending on which research paper you read."

There's another point to consider here. Using death estimates is the scariest way to talk about the risk from flu, because 8,000 thousand sounds like a lot of deaths. But if you ask, "8,000 deaths out of how many people?" suddenly the risk seems much smaller. In fact, it would be 8,000 deaths among 35 million Canadians. In other words, in a normal flu season, about 0.02 per cent of Canadians are in danger of dying from the flu, using the highest estimate. Another way to look at it is this: 99.98 per cent of Canadians will not die of flu this year.


[link to healthsentinel.com]

according to the CDC's National Center for Health Statistics (NCHS), “influenza and pneumonia” took 62,034 lives in 2001 - 61,777 of which were attributed to pneumonia and 257 to flu, and in only 18 cases was flu virus positively identified. Between 1979 and 2002, NCHS data show an average 1348 flu deaths per year (range 257 to 3006).’

The CDC and news media frequently proclaim that there are about 36,000 influenza-associated deaths annually. Review of the mortality data from the CDC’s National Vital Statistics System(NVSS) reveals these estimates are grossly exaggerated. The NVSS reports preliminary mortality statistics and distinguishes between influenza-related deaths and pneumonia-related mortality. When the final report is issued, influenza mortalities are combined with the far more frequent pneumonia deaths, yielding an exaggerated representation of influenza deaths. Pneumonia related mortality due to immunosuppression, AIDS, malnutrition, and a variety of other predisposing medical conditions is therefore combined with seasonal influenza deaths. The actual influenza related deaths for the years 1997 to 2002 ranged from 257 to 1,765 annually. These values are further overestimated by combining deaths from laboratory-confirmed influenza infections with cases lacking laboratory confirmation.”