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
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.
-
Music reviews: Chance the Rapper, Cass McCombs, and Molly TuttleFeature "Star Line," "Interior Live Oak," and "So Long Little Miss Sunshine"
-
Film reviews: Eden and Honey Don't!Feature Seekers of a new utopia spiral into savagery and a queer private eye prowls a high-desert town
-
Critics' choice: Three chefs fulfilling their ambitionsFeature Kwame Onwuachi's grand second act, Travis Lett makes a comeback, and Jeff Watson's new Korean restaurant
-
Texas declares end to measles outbreakSpeed Read The vaccine-preventable disease is still spreading in neighboring states, Mexico and Canada
-
RFK Jr. shuts down mRNA vaccine funding at agencySpeed Read The decision canceled or modified 22 projects, primarily for work on vaccines and therapeutics for respiratory viruses
-
Measles cases surge to 33-year highSpeed Read The infection was declared eliminated from the US in 2000 but has seen a resurgence amid vaccine hesitancy
-
Kennedy's vaccine panel signals skepticism, changeSpeed Read RFK Jr.'s new vaccine advisory board intends to make changes to the decades-old US immunization system
-
Kennedy ousts entire CDC vaccine advisory panelspeed read Health Secretary RFK Jr. is a longtime anti-vaccine activist who has criticized the panel of experts
-
RFK Jr. scraps Covid shots for pregnant women, kidsSpeed Read The Health Secretary announced a policy change without informing CDC officials
-
New FDA chiefs limit Covid-19 shots to elderly, sickspeed read The FDA set stricter approval standards for booster shots
-
US overdose deaths plunged 27% last yearspeed read Drug overdose still 'remains the leading cause of death for Americans aged 18-44,' said the CDC
