Relying on your subjective perception isn’t only unreliable, it’s biased by your existing beliefs. To find out if the flu vaccine really is worthwhile, you need to look at objective numbers. Each year, only about 0.0001 percent of people who get the vaccine have a severe allergic reaction (that’s one person per million doses). And there’s no way of knowing how many people contract the flu before the vaccine has reached its peak effectiveness. Influenza can incubate for up to four days, and the flu shot isn’t fully effective until two full weeks after administration.
