This flu season, national health authorities made a relatively poor guess of which flu strain would be going around. As a result, the media has endlessly repeated a study finding that this year's flu vaccine is only "23 percent effective." Offhand, you might guess that this means only 23 percent of vaccinated people are protected against the flu — or maybe you could somehow get one-fourth of a case of the flu?
Not quite. It turns out this definition is quite complicated, and isn't even a measurement of the general population, but instead of people with acute respiratory infections. Aaron Carroll carefully explains the details below, but the bottom line is that even when the flu shot isn't a great match, it's still worth getting. —Ryan Cooper
Subscribe to The Week
Escape your echo chamber. Get the facts behind the news, plus analysis from multiple perspectives.
Sign up for The Week's Free Newsletters
From our morning news briefing to a weekly Good News Newsletter, get the best of The Week delivered directly to your inbox.
From our morning news briefing to a weekly Good News Newsletter, get the best of The Week delivered directly to your inbox.
-
Today's political cartoons - February 1, 2025Cartoons Saturday's cartoons - broken eggs, contagious lies, and more
-
5 humorously unhealthy cartoons about RFK Jr.Cartoons Artists take on medical innovation, disease spreading, and more
-
Brodet (fish stew) recipeThe Week Recommends This hearty dish is best accompanied by a bowl of polenta
-
FDA approves painkiller said to thwart addictionSpeed Read Suzetrigine, being sold as Journavx, is the first new pharmaceutical pain treatment approved by the FDA in 20 years
-
Study finds possible alternative abortion pillSpeed Read An emergency contraception (morning-after) pill called Ella could be an alternative to mifepristone for abortions
-
California declares bird flu emergencySpeed Read The emergency came hours after the nation's first person with severe bird flu infection was hospitalized
-
Bird flu one mutuation from human threat, study findsSpeed Read A Scripps Research Institute study found one genetic tweak of the virus could enable its spread among people
-
Dark chocolate tied to lower diabetes riskSpeed Read The findings were based on the diets of about 192,000 US adults over 34 years
-
ACA opens 2025 enrollment, enters 2024 raceSpeed Read Mike Johnson promises big changes to the Affordable Care Act if Trump wins the election
-
McDonald's sued over E. coli linked to burgerSpeed Read The outbreak has sickened at least 49 people in 10 states and left one dead
-
Texas dairy worker gets bird flu from infected cowSpeed Read The virus has been spreading among cattle in Texas, Kansas, Michigan and New Mexico
