Researchers from the European University and the Sergey Berezin Medical Institute (MIBS) have calculated the effectiveness of Russian vaccines against lung damage during COVID-19 waves caused by the Delta and Omicron strains. The effectiveness of two doses of Sputnik V was 56%. The effectiveness of three doses was 71%. EpiVacCorona was not shown to be effective. The work is published as a preprint.
The researchers collected data on patients with a positive PCR test results referred for computed tomography at two MIBS outpatient centers from October 1, 2021 to April 28, 2022. "Cases" were patients with lung damage according to the CT data. The control group was patients without lung damage (test negative study design).
Mikhail Cherkashin, co-author of the study, deputy chief MIBS physician remarked:
We did not consider hospitalization as an outcome, unlike in the previous study, since the criteria for hospitalization changed in the fall of 2021. According to the new criteria, older patients could be hospitalized, regardless of the degree of lung damage.
MIBS doctors collected data on the type of vaccine, the number of doses and the dates of vaccination. People who received a second dose of Sputnik V, EpiVacCorona or CoviVac at least 14 days before the referral for CT scans were considered fully vaccinated. The study included 23,996 people with coronavirus infection confirmed by a PCR test result. People with negative or questionable PCR results were excluded from the initial analysis. 11,288 (47%) had had at least one COVID-19 vaccine.
The effectiveness of three doses of Sputnik against lung damage was 71%. For EpiVacCorona the figure was 2%. For CoviVac it was 46%.
Anton Barchuk, co-author of the study, Associate Professor of Population Medical Research at Polymetal JSC, and Director of the Institute for Interdisciplinary Medical Research of the European University in St. Petersburg, commented:
Sputnik V protects against lung damage caused by new strains of SARS-CoV-2, and Sputnik Light can be used as a booster after vaccination or illness - this will increase the chances of avoiding a severe case of COVID-19.
Doctors recorded data on the vaccination status through patient self reporting. This was the main limitation of the study. Researchers also point to a possible selection error. In particular, some people who contracted COVID-19 after vaccination may have avoided additional screenings.
This is the third independent study of the effectiveness of Russian vaccines against coronavirus infection. In August 2021, researchers found that people vaccinated with Sputnik V were less likely to require hospitalization. According to the second study, Sputnik V is effective against symptomatic infection caused by the Delta variant of SARS-CoV-2.
Contacts:
Alexandra Vasilyeva,
Public Relations officer for Science, Institute of Interdisciplinary Medical Research (IMMI)
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