Studies confirm effectiveness of vaccines against Covid-19 delta strain
According to the U.S. Centers for Disease Control and Prevention (CDC), current anticoronavirus vaccines are still quite effective against the COVID-19 delta strain. This is borne out by the fact that people who are not vaccinated are 10 times more likely to get sick than those who are vaccinated.
For the past two to three months (April-July), the delta virus has become predominant, accounting for about 99% of cases in the United States. Studies have shown that existing vaccines remain effective against the delta strain: the probability of avoiding hospitalization has dropped from only 92% to 90%, and “protection” against death has dropped from 94% to 91%. At the same time, the effectiveness of vaccines against baseline symptoms decreased from 91% to 78%.
Another study compared the effectiveness of Moderna and Pfizer vaccines in the United States. Moderna was twice as effective in this “competition. Experts attribute such unusual results to the fact that Moderna doses are much higher than those of Pfizer and a number of other factors. For example, study participants did not track time since vaccination, so it is not known how this might have affected the decrease in efficacy.
However, according to one study participant, Sean Grannis of Indiana University School of Medicine, their main outcome is that the vaccines against severe forms of COVID-19 are still highly effective.