Vaccinated residents of St. Petersburg with symptomatic COVID-19 are almost 5 times less likely to have severe disease. Vaccine effectiveness against hospitalization was 81% for fully vaccinated individuals.
The European University at St. Petersburg, Medical Institute named after Berezin Sergey and Tarusa hospital conducted an observational study to assess the effectiveness of vaccination during the third wave of the pandemic caused by the Delta variant in St. Petersburg.
The study included data on 13,894 symptomatic individuals with confirmed SARS-CoV-2 infection referred for computed tomography triage on July 3 — August 9, 2021. Based on computed tomography results and symptoms, 495 patients were referred to the hospital and 13,399 — to outpatient follow-up.
Complete vaccination (two weeks or more after the second dose) reduced the participants’ odds of referral to the hospital by 81%. Vaccinated people were also less likely to have severe lung disease.
“One of our study limitations is the absence of information about the type of vaccine, but according to the official statistics, by July 23, 2021 96% of St. Petersburg residents who received at least one dose were vaccinated by Gam-COVID-Vac (Sputnik V). We assume that our results describe the effectiveness of Sputnik V against hospital admission amid the third wave caused by the Delta variant,” said Anton Barchuk, Polymetal Associate Professor of Epidemiology, Head of Institute for Interdisciplinary Health Research, European University at Saint Petersburg.
Among all symptomatic study participants less than 10% were fully vaccinated, compared to almost 20% in the general population. Vaccination could potentially reduce the risk of symptomatic disease or the probability of becoming infected, but more studies are needed.
“The lack of evidence about real-world effectiveness of vaccination in Russia is among the reasons why people do not want to take a shot. We hope our data will help communicate the balance of benefits and harms of COVID-19 vaccination”, said Artemy Okhotin, physician and cardiologist from Tarusa hospital.
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