COVID Vaccines Are Over 90% Effective at Preventing Deaths From Delta Variant

Vaccination is more than 90 percent effective in preventing deaths from the Delta variant of Covid-19, according to the first country-level death data.

The Pfizer-BioNTech vaccine is 90 percent effective and the Oxford-AstraZeneca vaccine 91 percent effective at preventing deaths in people who have been double vaccinated but have tested positive for coronavirus in the community, research shows.

The study, which uses data from the Scotland-wide EAVE II Covid-19 monitoring platform, is the first nationwide to show how effective vaccines are at preventing death from the Delta variant, which is now the dominant form of Covid-19 is in the UK and many other countries.

Researchers analyzed data from 5.4 million people in Scotland between April 1 and September 27, 2021.

During this time, 115,000 people tested positive for Covid-19 through a PCR test conducted in the community rather than in hospital, and 201 deaths from the virus were recorded.

The Moderna vaccine is also available in Scotland and no deaths have been recorded in those who have been double vaccinated with it. Consequently, it has not been possible to estimate its effectiveness in preventing death, researchers said.

Researchers defined death from Covid-19 as anyone who died within 28 days of a positive PCR test, or with Covid-19 recorded as the cause of death on their death certificate.

The research team from the Universities of Edinburgh and Strathclyde and Public Health Scotland analyzed a dataset as part of the EAVE II project, which uses anonymized linked patient data to monitor the pandemic and vaccine roll-out in real time.

The results are published as a letter in the New England Journal of Medicine.

The researchers say that to increase confidence in these early findings, the study should be repeated in other countries and institutions, and with a longer follow-up time after full vaccination.

The team says that due to the observational nature of the study, data on vaccine effectiveness should be interpreted with caution and it is not possible to make a direct comparison between the two vaccines.

Professor Aziz Sheikh, director of the Usher Institute at the University of Edinburgh and head of the EAVE II study, said: “Now that the Delta variant is the dominant species in many places worldwide and carries a higher risk of hospitalization than previous variants seen in the UK it is reassuring to see that vaccination offers such a high protection against death very soon after the second dose.”

“If you still haven’t taken up your offer to get vaccinated, I would encourage you to do so based on the obvious benefits it offers.”

Professor Chris Robertson, University of Strathclyde and Public Health Scotland, said: “This study demonstrates the value of performing analyzes of routine health data that are available in near real time.

“Our findings are encouraging to show that the vaccine continues to be an effective measure to protect both ourselves and others from death from the most dominant strain of Covid-19. It is very important to validate these early results in other settings and with a longer follow-up study.”

Reference: “BNT162b2 and ChAdOx1 nCoV-19 Vaccine Effectiveness against Death from the Delta Variant” Oct 20, 2021, New England Journal of Medicine.

The study was funded by the Medical Research Council, the UK Research and Innovation Industrial Strategy Challenge Fund, the National Institute for Health Research and Health Data Research UK (HDR UK), and was supported by the Scottish Government.

Additional support was provided through the Scottish Government’s Director-General for Health and Social Care and the UKRI COVID-19 National Core Studies Data and Connectivity program led by HDR UK.