Israel research: One Pfizer jab reduces Covid infections 75%

A Sheba Medical Center study published in UK medical journal "The Lancet" justifies delaying second doses due to vaccine shortages.

The UK peer-reviewed medical journal "The Lancet" has published a study by Israel's largest hospital, the Sheba Medical Center at Tel Hashomer, of 9,109 of its health-care workers, of whom 7,214 were inoculated against Covid-19 with the Pfizer vaccine. The research supports previous studies that found that the vaccine was extremely effective in reducing severe Covid-19 and easing infection from two weeks after the first jab and justifies the policies of countries delaying second doses due to vaccine shortages.

The research found that two weeks after the first Pfizer vaccination, there was a 75% reduction in overall Covid-19 infections and an 85% reduction in symptomatic Covid-19 infections (light and serious). This was compared with the health-care workers who were not vaccinated. After the second Pfizer dose and another week, the efficacy rose to 96%, similar to the results in Pfizer's clinical trial.

So the research found, among other things, that there was high efficacy in preventing infection and morbidity after the first dose but with two reservations.

The first was that, "Lack of active laboratory surveillance in the cohort might have resulted in an underestimation of asymptomatic cases." Although according to the data 42% of those in the study were asymptomatic patients, so that the study does allow a certain snapshot of this group, and the differences between them were substantial.

The second reservation was that, "The early rate reductions seen in health care workers might differ from vaccine efficacy reported in the general population due to their higher exposure risk or due to exposure to more virulent or infectious strains."

The main conclusion of the research was the high efficacy of just one dose in preventing the virus. "Our data show substantial early reductions in SARS-CoV-2 infection and symptomatic COVID-19 rates following first vaccine dose administration. Early reductions of COVID-19 rates provide support of delaying the second dose in countries facing vaccine shortages and scarce resources, so as to allow higher population coverage with a single dose. Longer follow-up to assess long-term effectiveness of a single dose is needed to inform a second dose delay policy."

Published by Globes, Israel business news - - on February 19, 2021

© Copyright of Globes Publisher Itonut (1983) Ltd. 2021

Twitter Facebook Linkedin RSS Newsletters גלובס Israel Business Conference 2018