Global health officials rolled back the Oxford-AstraZeneca vaccine after a study showed it had very little effect against the new Covid-19 variant which is now quickly spreading in South Africa.
The decision to begin distribution of about 330 million doses of AstraZeneca's vaccine this month in South Africa has been put on hold to further study the effects of the vaccine before its rollout.
The decision is based on a small study that included 2,000 people whose median age was 31 years old. The study defined mild disease as having at least one symptom of COVID-19. Since the target population was at low risk, the protection against moderate-severe disease, hospitalization or death could not be assessed in this study which is yet awaiting peer review.
"These findings also force us to recalibrate thinking about how to approach the pandemic virus and shift the focus from the aspirational goal of herd immunity against transmission to the protection of all at-risk individuals in the population against severe disease," said Shabir Madhi, Director of the Vaccines & Infectious Diseases Analytics (VIDA) and Chief Investigator on the trial in South Africa.
The effectiveness of vaccines against the mutated variants of the Coronavirus was a concern that loomed large over the currently adopted strategies to come out of the pandemic. If the vaccines do not work against the mutated variants, it will mean that the battle against the virus has not yet begun and the world will take a much longer time before it can emerge out of the current situation.
"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. 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," said Sarah Gilbert, Professor of Vaccinology at the University of Oxford.