Flu season thoughts.

I haven't had a flu vaccine in decades, and, statistically speaking, I shouldn't be worried, because the flu only afflicts roughly 10-20% of the population. Thusly, I think that I've only ever had the flu, once.

This compares to the common cold, which I, on average, catch once a year.

Of late, both the national and  Portland news media outlets have been pushing the narrative that the flu season is getting worse. Concurrently, they're also reporting that because of the mismatch of the vaccine, the vaccine is not as effective, though they say that you should nonetheless get the shot, because it offers some protection.

Naturally, I had to do some research.

Contrary to national reports, we're well on our way down from the flu season's peak.

Google Flu Trends

Indeed, we peaked in early December, nationally, according to Google Flu Trends. So, how are we doing in Oregon? Well, that map above pretty much tells you how Oregon is doing. Below is confirmation that it has been a mild season, overall, in the State of Oregon.

So, how is the flu season doing in Portland? Well, it's still getting hot (pun intended), but if you extrapolate the change in slope, Portland's flu season will either peak in the next week or two, then begin to drop off.

Now consider that it takes about two weeks for the flu vaccine to reach full effectiveness, so if you run out to get the shot, you will likely miss the peak of the season in Portland.

But more critically, because of this season's mismatch, the vaccine is likely only about 50-55% effective. In a good year, the vaccine is about 80-85% effective.

In fact, the number of people needed to vaccine in order for one person to avoid the flu, is roughly 71, and that's when there's a perfect match. (By comparison, NNV for seniors against pneumonia, ranges from 600 - 2000, while NNV for seniors against shingles, ranges from 11 - 165.) Note: that does not mean that the 70 people who were vaccinated would end up with the flu, but that because the flu infects just 10-20% of the population, you need to vaccinate 71 people to stop one infection.

So should you get a shot?

Well, that depends on your perspective. The cost is often free up front, making the choice a relatively simple cost-benefit-risk analysis. Despite what you may hear about side-effects of vaccines, there is no actual link between vaccines and certain specific diseases or conditions. However, I am quite sure that there is a genetic component to vaccine response -- that is to say that if viruses can mutate, then surely humans have minute variations that is responsible for how our bodies respond to vaccines.

Frankly, I would rather that virologists focus on a vaccine against rhinovirus, the common cold, because rhinoviruses are much more prevalent.

But no, I will not be getting the flu vaccine. Maybe next season.

References:

1. http://summaries.cochrane.org/CD001269/ARI_vaccines-to-prevent-influenza-in-healthy-adults
2. http://link.springer.com/article/10.1186%2F1741-7015-11-153
3. http://www.cdc.gov/vaccines/acip/recs/grade/pneumo-vac-adult.html
4. http://www.jstor.org/discover/10.2307/41996069