It’s hard to tell because they haven’t been directly compared in studies. But experts believe that the vaccines are similar in the most important thing: preventing hospitalizations and deaths.
“Fortunately, it seems that all these vaccines protect us from serious disease,” said Dr. Monica Gandhi of the University of California, San Francisco, who mentioned results of studies of five vaccines that are being used in different parts of the world. as a sixth still under review.
And tests in the real world, as millions of people get vaccinated, show that they are all working very well.
Still, people wonder if one is better than another, since studies conducted before the vaccines were distributed showed varying levels of effectiveness. The problem is that they don’t offer equivalent comparisons.
For example, the two-dose vaccines from Pfizer and Moderna have been found to be about 95% effective in preventing disease. The studies of these drugs counted one case of COVID-19 whether it was mild, moderate or severe, and they were done before worrying variants of the virus began to circulate.
Johnson & Johnson then tested its one-dose vaccine and did not count minor illnesses. His drug was 66% effective against moderate to severe disease in a large international study. In the United States, where the variants are less widespread, it was 72% effective. Most importantly, once the vaccine was in effect, it prevented hospitalizations and deaths.
The effectiveness data from studies of the two-dose AstraZeneca vaccine, used in many countries, has been questioned. But experts also agree that these injections protect against the worst effects of COVID-19.
In different parts of the world, hospitalizations drop in countries that have started vaccinations, such as Israel, England and Scotland, regardless of what type of vaccines they use. And the first US government review of vaccinated essential workers yielded new evidence that Pfizer and Moderna vaccines offer high protection – 90% – against contagion, whether there are symptoms or not.
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