The main concern of B.1.1.7 is that it is highly contagious and that it is spreading rapidly among the unvaccinated, potentially overwhelming hospitals in areas where cases are soaring.
Do the vaccines work against B.1.1.7?
All of the main vaccines used – Pfizer-BioNTech, Moderna, Johnson & Johnson, AstraZeneca, Sputnik, and Novavax – have been shown to be effective against B.1.1.7. We know this from a large number of studies and indicators. First, scientists used the blood of vaccinated patients to study how well vaccine antibodies bind to a variant in a test tube. The vaccines have all proven themselves relatively well against B.1.1.7. There is also data from clinical trials, notably from Johnson & Johnson and AstraZeneca (the most widely used vaccine in the world), showing that it is effective against both infections and severe ones in areas where B.1.1.7 is circulating Diseases are highly effective. And in Israel, for example, where 80 percent of the eligible population are vaccinated (all with the Pfizer shot), even as schools, restaurants, and workplaces open, case numbers drop, suggesting vaccines may introduce new infections, including those , curb caused by variants.
If the vaccines are working, why keep hearing about breakthrough cases?
No vaccine is child’s play, and although the Covid vaccines offer a high level of protection, people who have been vaccinated sometimes still get infected. But breakthrough cases from vaccinated people are very rare, even when variants trigger an increase in the number of cases. And the vaccines clearly prevent serious illness and hospitalization in the few vaccinated patients who become infected.
What is the risk of infection after vaccination? Nobody really knows, but we have some pointers. For example, during the Moderna study, only 11 out of 15,210 vaccinated patients were infected. Both Pfizer and Moderna are currently conducting more detailed studies of breakthrough cases in vaccinated subjects and should publish these data soon.
April 15, 2021, 4:49 p.m. ET
Two real-world studies of vaccinated health care workers at much higher risk of virus exposure than the rest of us, offer hopeful signs. One study found that only four out of 8,121 fully vaccinated employees at the University of Texas’ Southwestern Medical Center in Dallas were infected. The other found that only seven of 14,990 employees at UC San Diego Health and the David Geffen School of Medicine at the University of California at Los Angeles tested positive two or more weeks after receiving a second dose of Pfizer-BioNTech or Moderna vaccinations . Both reports were published in the New England Journal of Medicine and are a sign that breakthrough cases were uncommon even in those who were frequently exposed to sick patients, although cases in the United States rose sharply. Most importantly, patients infected after vaccination had mild symptoms. Some people had no symptoms at all and were only discovered through tests in studies or as part of their independent medical care.
Researchers are still investigating whether the variants may increase the number of breakthrough cases or whether vaccine antibodies decline over time. So far, data from Moderna shows that the vaccine is still 90 percent effective after at least six months. Pfizer has reported similar results.
A recent study of 149 people in Israel who became infected with the Pfizer vaccine after vaccination found that a variant first identified in South Africa was more likely to cause breakthrough infections. However, these eight infections occurred between the seventh and the 13th day after the second dose. “We didn’t see a South African variant 14 days after the second dose,” said Adi Stern, the study’s lead author, professor at the Shmunis School of Biomedicine and Cancer Research at Tel Aviv University. “It was a small sample size, but it is very likely that two weeks after the second dose the level of protection may increase and the South African variant will be blocked completely. That gives us more room for optimism. “