The Hebrew University rated all current vaccines available against coronavirus, and found that people vaccinated with the Pfizer version were 85% less likely to get corona compared to vaccines from some other companies. Here are all the details.
In recent days, everyone has been worried about the effectiveness of vaccines against the Omicron strain, but let’s emphasize that not all vaccines are equally effective.
Some vaccines give more protection and some less. A new study conducted by Hebrew University examined all existing vaccines and found which are the most effective. Researchers found that people vaccinated with Pfizer are 85% less likely to get corona compared to those vaccinated with the AstraZeneca and Johnson & Johnson vaccines.
The researchers, from the School of Pharmacy, part of the Faculty of Medicine at the Hebrew University of Jerusalem, compared the efficacy of nine vaccines against corona symptoms and the severity of the disease in the adult population. In the study, published in the journal Scientific Reports from the publishers of Nature, researchers compared the effectiveness of new vaccines against corona based on the results of clinical trials conducted on each individual vaccine.
The method of analysis used was network meta analysis (NMA), a method that allows scientists to connect and compare results from different studies, even when none of the studies was a direct efficacy test of one vaccine compared to another.
The use of data analysis makes it possible to evaluate the relative efficacy between each pair of vaccines and even rate them in terms of the probability of which is most effective. The vaccines included in the study were: two mRNA vaccines from Pfizer and Moderna; two vaccines that use a different virus (adenovirus) that carry a DNA fragment of the coronavirus - a vaccine from the AstraZeneca company and a Sputnik vaccine; a Johnson’s vaccine that uses adenovirus to transmit the virus’ spike protein; a vaccine containing the S protein made by Novavax; and three vaccines based on "classical" technology containing inactive coronavirus - two from Sinopharm and one from Sinovac.
The researchers rated the probability that a particular vaccine would protect better compared to all other vaccines, and these are the results obtained:
- Pfizer 95%
- Moderna 84%
- Sputnik 78%
- Novavax - 70%
- Sinovac - 57%
- Two vaccines from Sinopharm - 33% and 43%
- Johnson and AstraZeneca - 20%
Vaccines with mRNA are more efficient
According to the results of the study, subjects vaccinated with mRNA vaccines from Pfizer and Moderna have the lowest relative risk of developing symptomatic corona, compared to other recipients of the vaccines tested in the data analysis.
As mentioned, those vaccinated with the Pfizer version had a 85% lower risk of developing symptomatic disease compared with those vaccinated with AstraZeneca or Johnson versions. A similar figure (79%) was observed among Moderna vaccines compared to AstraZeneca and Johnson. The two mRNA vaccines were rated as having the highest probability of preventing symptomatic disease in the adult population compared to other vaccines.
In addition, a trend of higher efficacy of mRNA vaccines in the prevention of severe corona has been observed. The researchers found no difference between the different vaccines in terms of their effectiveness in preventing symptomatic disease in a population over the age of 65.
The results of the study could assist governments in determining vaccination policies in combination with other variables such as the availability of the various vaccines, side effects, costs, storage conditions, transportation and more. However, the researchers qualify the results and note that the NMA method combines the results of different studies, assuming that the studies are similar in terms of design and population, when in practice there are always differences to some degree between the studies.
This is especially important in the context of corona studies, where we see variables of morbidity in terms of population morbidity, geographical location, different variants and their resistance to vaccines. Each variable may affect the results of vaccine efficacy in each study individually and thus affect relative efficacy.
The research was led by researchers Dr. Victoria Rothschild, Dr. Bruria Hirsch-Raccah, Dr. Ian Miskin, Prof. Mordechai Muscat and Prof. Ilan Matok.