New Studies Suggest Existing Vaccines Work Well Against Virus Variants

Several new studies published this week offer hope that existing COVID-19 vaccines are highly effective against dangerous virus variants

The world is in a race against time and COVID-19, pushing to vaccinate as many people as possible, even as more contagious and potentially more deadly variants of the virus are constantly emerging — and spreading. But several new studies this week offer a glimmer of hope that the vaccines that are being widely used now may be enough to hold back variants of the virus that are rapidly spreading around the world right now.

Two published studies found that Pfizer’s vaccine, one of the first in the world to be approved for emergency use and heavily distributed in the United States, is incredibly effective in preventing death and severe disease, even against two of the more worrying variants circulating around the world.

The first study suggested that a two-dose regimen of Pfizer’s shot is 87 to 89.5 percent effective in preventing infection with the B.1.1.7 variant, first identified in the U.K. And the study also showed the vaccine is 72.1 to 75 percent effective preventing infection with the B.1.351 variant, first identified in Brazil. Both variants are believed by scientists to be more contagious, and have the potential to cause more severe COVID-19 symptoms and cause more deaths than previous forms of the disease.

The second study used real-world infection data from Israel, where B.1.1.7 accounts for nearly 95 percent of all infections. That study showed that Pfizer’s vaccines were more than 95 percent effective at preventing infection, hospitalization, and death among the general population, and around 94 percent effective at preventing illness in older people. More than half of Israel’s population has been fully vaccinated so far.

Of the Pfizer study, Dr. Annelies Wilder-Smith, a researcher in infectious diseases at the London School of Hygiene and Tropical Medicine says, “At this point in time, we can confidently say that we can use this vaccine, even in the presence of circulating variants of concern.”

Moderna also announced the results of an early stage trial this week that indicated its vaccine, with a single-dose booster, is effective against variants discovered in South Africa and Brazil. That study has not yet been peer-reviewed or published, so scientists urge cautious optimism about those results.

In countries where a high percentage of the population has been vaccinated, like Israel, infections and deaths have declined sharply, even as public spaces and events have opened up. With continuous review, the vaccines being used in most parts of the world have continued to be found safe and effective, offering a clear path out of the pandemic — provided enough people are willing to get their shots.