Most Americans do not have maximum vaccine protection against COVID


Illustration of two direction signs in the form of syringes pointing in different directions

Illustration: Sarah Grillo/Axios

Most US adults — including most of America’s seniors — are heading into the holiday season and an expected increase in cases without the maximum level of vaccine protection against the virus.

Driving the news: Only 36% of American seniors — and just 16% of the population 18 and older — received the updated booster shot that became available in September.

Why it matters: The effectiveness of vaccines decreases over time, which means that even vaccinated people who haven’t had a shot in a while may not be well protected against serious infections.

The big picture: All the data released over the past two years says that vaccines are effective. The problem is twofold: effectiveness has changed as the virus has evolved, and it also wears off if you haven’t had your last injection in a while.

  • The lesson is that vaccines work, getting a booster shot is important — especially for older, vulnerable people — and people who haven’t had a shot recently are at significantly greater risk than if they had.
  • The effectiveness of vaccines against serious illness and death lasts longer than the protection against becoming ill with the virus, but it still decreases significantly.
  • Currently, hospitalizations for COVID are increasing, especially among the elderly, at least partially reflecting the lack of uptake of booster shots.

Driving the news: Recent data from the CDC quantified the value of updated booster shots, which are directed against both the parent virus strain and the Omicron variant.

  • Two studies released earlier this month presented a mixed picture of the effectiveness of injections against hospitalization. One found that the updated vaccine was 57% effective against hospitalization when compared with no vaccination.
  • Compared with receiving the last dose five to seven months earlier, the updated shot was 38% more effective at preventing hospitalization, the study found — but if the last dose was 11 months earlier or more, the updated shot was 45% more effective.

The second study found greater efficacy among adults aged 65 and over. Compared with unvaccinated people, the updated vaccine was 84% ​​effective against hospitalization.

  • Compared with people who received only two or more doses of the original injection, the updated one was 73% effective.
  • The vaccine’s relative effectiveness is affected by the fact that many Americans — including unvaccinated people — have already been infected with COVID, meaning they may have some natural immunity.

Yes but: Shots are much less effective at preventing routine infections, and some scientists say the value of boosters may be more limited in younger populations who are generally not at risk for severe cases anyway.

  • “There’s a big difference between what’s happening to young, healthy people and what’s happening to older, sick people,” said Cornell virologist John Moore. boosters.”

More Zoom: Many Americans don’t feel they need the updated photos.

  • In a recent KFF poll, 44% of vaccinated people surveyed who did not receive an up-to-date booster dose said they don’t think they need it, including nearly two-thirds of Republican or Republican-leaning respondents.
  • Another 37% said they didn’t think the benefit was worth it.

Between the lines: A recent UK Health Safety Agency report focusing on older Omicron variants found that six to eight months after receiving a second dose of the Pfizer or Moderna vaccine, protection against hospitalization and mortality dropped to around 50 % compared to unvaccinated people.

  • This compares to about 80% effectiveness in the first three months after the injection.
  • People who received a third dose of either vaccine did slightly better, with about 60% effectiveness against hospitalization nine months earlier.

What are we watching: The virus has evolved since updated boosters were released, and the threat of new variants that may further evade vaccine protection has not gone away.