Flu has been bad this season but it appears to have peaked

Based on several different trackers, it looks like flu this season has been bad. According to the CDC (as reported by Margot Sanger-Katz of The New York Times): "Nationwide, we’re on track for a nasty flu season, with both a large number of cases and many severe ones that require hospitalizations, according to the Centers for Disease Control and Prevention."

One flu tracker maintained by the CDC is based on outpatient visits to hospitals because of flu symptoms (link, Figure 1):

Figure 1. Flu tracker from the CDC based on outpatient hospital visits for flu symptoms (snapshot from 1/9/15). The 2014-2015 season (red line with triangles, see key) is compared to the past 4 seasons (from CDC).

As one can see, compared to the past 4 years, this year's flu season (red line) ranks with the 2012-13 season as one of the worst.

Another tracker that you can follow is Google Flu Trends (Figure 2), which relies on the number of flu-related Google Searches to estimate the severity of the flu outbreak. It also shows that this season is bad with only the 2012-13 season worse.

Figure 2. Google Flu Trends (1/9/15). This year (dark blue) compared to the past 6 years. 2012-2013 is the only year with a higher peak.

The good news is that both trackers indicate that the worst of the flu season may be over. It is too early to say for certain, but the number of cases or severity in both graphs appear to have peaked and is now declining. I will check both trackers next week to see if this downward trend continues.

However you should not let your guard down. One of the issues compounding the spread of flu this year is that the flu vaccine has not been as effective as in previous years. The most prevalent flu strain (H3N2) seems to have mutated sufficiently to avoid the antibodies induced by the vaccine. Of course, you should still get your flu shot but you should be aware it will most likely offer only 50% protection (i.e. reduced risk) as opposed to 60-90% in a typical year.

Just as a reminder, flu can have serious health consequences (especially compared to a cold) with approximately 25,000 deaths per year in the U.S. attributed to flu-related causes. Those at most risk are the elderly and kids. The problems arise from complications from being sick with flu. For example, flu can lead to pneumonia and bronchitis which can cause death if severe enough and not treated properly.

To avoid the flu, it is best to get your flu shot. In addition, wash your hands carefully and often with soap, avoid touching your eyes, nose, or mouth, and try to avoid close contact with sick people.