The main concern about B.1.1.7 is that it is highly contagious and spreads rapidly among unvaccinated, potentially overwhelming hospitals in areas where cases are increasing.
Do vaccines work against B.1.1.7?
All 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 variety of studies and indicators. First, the scientists used the blood of vaccinated patients to study how well vaccine antibodies bind to a variant in a test tube. The vaccines all performed relatively well against B.1.1.7. There is also clinical trial data, particularly from Johnson & Johnson and AstraZeneca (which is the most widely used vaccine in the world), which shows that they are very effective against serious infections and diseases in regions where B.1.1.7 circulates. And in Israel, for example, where 80% of the eligible population is vaccinated (all with the Pfizer vaccine), the number of cases is dropping, even as schools, restaurants and workplaces open, suggesting that vaccines reduce new infections, including those caused by variants.
If vaccines work, why do I keep hearing about “breakthrough” cases?
No vaccine is foolproof, and even though Covid vaccines are highly protective, sometimes people vaccinated are still infected. But breakthrough cases of people vaccinated are very rare, even if the variants are fueling an increase in the number of cases. And vaccines clearly prevent serious illness and hospitalization in the few vaccinated patients who are infected.
So what is the risk of getting infected after vaccination? No one knows for sure, but we have some clues. During the Moderna trial, for example, only 11 out of 15,210 vaccinated patients were infected. Pfizer and Moderna are currently conducting more detailed studies of breakthrough cases among vaccine trial participants and are expected to release this data shortly.
Two real-world studies of vaccinated healthcare workers, who have a much higher risk of exposure to the virus than the rest of us, offer encouraging signs. One study found that only four of 8,121 fully vaccinated employees at the University of Texas at Dallas’ Southwestern Medical Center were infected. The other found that only seven of the 14,990 workers at UC San Diego Health and the David Geffen School of Medicine at the University of California at Los Angeles tested positive two weeks or more after receiving a second dose of Pfizer-BioNTech or Moderna. vaccines. Both reports were published in the New England Journal of Medicine and are a sign that although cases were on the rise in the United States, breakthrough cases were rare, even among people often exposed to sick patients. More importantly, patients infected after vaccination exhibited mild symptoms. Some people had no symptoms and were only discovered through testing in studies or as part of their independent medical care.
Researchers are still studying whether the variants could possibly increase the number of breakthrough cases or whether vaccine antibodies start to decline over time. So far, data from Moderna shows that the vaccine remains 90% effective after at least six months. Pfizer reported similar results.
A recent study of 149 people in Israel who were infected after vaccination with the Pfizer vaccine suggested that a variant first identified in South Africa was more likely to cause rupture infections. However, these eight infections occurred between days seven and 13 after the second dose. “We didn’t see any South African variants 14 days after the second dose,” said Adi Stern, lead author of the study, a professor at the Shmunis School of Biomedicine and Cancer Research at Tel Aviv University. “It was a small sample size, but it is very possible that two weeks after the second dose the level of protection will increase and completely block the South African variant. This gives us more room for optimism. “