Oxford/AstraZeneca COVID-19 vaccine offers limited protection against South African variant

Oxford/AstraZeneca vaccine offers limited protection against mild disease caused by COVID-19 variant

Analysis submitted as a pre-print prior to peer-review publication has shown that a two-dose regimen of the Oxford/AstraZeneca COVID-19 vaccine provides minimal protection against mild-moderate COVID-19 infection from the coronavirus variant first identified in South Africa.

The early data appears to confirm that mutations in the virus seen in South Africa will allow ongoing transmission of the virus in vaccinated populations, as has been recently reported even in those with prior infection due to earlier circulating variants.

In the study of approximately 2,000 volunteers who were on average 31 years old, mild disease was defined as at least one symptom of COVID-19. Protection against moderate-severe disease, hospitalisation or death could not be assessed in the study as the target population were at such low risk.

Work is already underway at the University of Oxford and in conjunction with partners to produce a second generation of the vaccine which has been adapted to target variants of the coronavirus with mutations similar to B.1.351, if it should prove necessary to do so.

Shabir Madhi, Professor of Vaccinology and Director of the Vaccines & Infectious Diseases Analytics (VIDA) Research Unit at University of the Witwatersrand, and Chief Investigator on the trial in South Africa said: “Recent data from a study in South Africa sponsored by Janssen which assessed moderate to severe disease, rather than mild disease, using a similar viral vector, indicated that protection against these important disease endpoints was preserved.

“These findings recalibrate thinking about how to approach the pandemic virus and shift the focus from the goal of herd immunity against transmission to the protection of all at risk individuals in population against severe disease.”

Andrew Pollard, Professor of Paediatric Infection and Immunity, and Chief Investigator on the Oxford vaccine trial, said: “This study confirms that the pandemic coronavirus will find ways to continue to spread in vaccinated populations, as expected, but, taken with the promising results from other studies in South Africa using a similar viral vector, vaccines may continue to ease the toll on health care systems by preventing severe disease.”

Sarah Gilbert, Professor of Vaccinology at the University of Oxford said: “Efforts are underway to develop a new generation of vaccines that will allow protection to be redirected to emerging variants as booster jabs, if it turns out that it is necessary to do so.

“We are working with AstraZeneca to optimise the pipeline required for a strain change should one become necessary. This is the same issue that is faced by all of the vaccine developers, and we will continue to monitor the emergence of new variants that arise in readiness for a future strain change.”