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Vaccines may be less effective against omicron, but boosters offer hope.

Early studies suggest that vaccines will still protect us, especially after getting a booster shot.

Lab-based studies of neutralizing antibody responses are a hint that protection from vaccines or previous infection might be diminished. Many of these same studies suggest that a third dose boosts antibodies back up to levels that should be protective against omicron.

Boosters can even provide more protection than the original shots because the body churns out antibodies that have evolved to better recognize the virus every time we’re exposed to its proteins, Chandran says. So after a boost, the body doesn’t just make more antibodies, they’re better ones, too (SN: 11/24/20). But because the immune response to infections is complex and varies from person to person, experts rely on studies from people in the real world to know for sure.

A study in South Africa, for instance, found that the effectiveness of two doses of Pfizer’s vaccine at stopping infection dropped from 80 percent pre-omicron to 33 percent during the omicron wave. There was a less dramatic drop in the shot’s effectiveness at preventing hospitalization. Before omicron, the jab was 93 percent effective; it decreased to 70 percent amid the new surge.

“It’s very heartening to see these results,” Gray, of the South African Medical Research Council, said at the December 14 news conference. Though the study didn’t look at the effect of booster shots, another dose should bring the vaccines’ effectiveness back up, she said. Analyses for comparing one or two doses of J&J’s COVID-19 vaccine are ongoing and should have results soon, Gray added. 

The findings are similar to early estimates out of the United Kingdom, which show Pfizer’s two-dose shot is around 30 percent effective against symptoms. A booster dose increased the effectiveness to between 70 percent to 75 percent, according to data from Public Health England. Still, there’s a lot of uncertainty because those findings are based on low numbers of cases. As time passes and more people get infected, researchers will get better estimates.

In the meantime, the worry about omicron has sparked a flurry of activity. People around the globe are upping their layers of protection with vaccinations, masks and pre-holiday COVID-19 tests. Experts expect that vaccines will largely keep vaccinated people out of the hospital. But with many people still unvaccinated across the United States, only time will tell whether the beginning of 2022 will be as devastating as the start of 2021.

“We are now waist-deep in the omicron wave,” infectious diseases physician Lemieux said in a December 20 call with journalists. The big question is how large the country’s omicron wave will be and what impact it will have on the health care system