- Early data from a pre-print study has shown that the AstraZeneca vaccine provides minimal protection against the South African variant.
- After Johnson & Johnson and Novavax, AstraZeneca is the third vaccine that has shown reduced efficacy against the new variant.
- Following the study’s result, South Africa has now put a temporary pause on the vaccine’s rollout in the country
In a briefing on Sunday, South Africa’s health minister announced a temporary pause on the rollout of AstraZeneca’s COVID-19 vaccine in the country. The decision follows the results of a recent study by the University of Witwatersrand. The study which is yet to be peer-reviewed showed that the AstraZeneca vaccine provided minimal protection against the B.1.351 variant. A strain that is responsible for driving the second wave in South Africa. Moreover, studies have shown that the B.1.351 strain is more contagious and virulent than other variants.
The AstraZeneca vaccine rollout needs to be put on a temporary halt while we get the clinical efficacy information in. And the way that we can do that is with the new approach to rollout.
Dr. Salim Abdool Karim, epidemiologist at Columbia University and part of a commission advising the South African government
Researchers presented the data from the study in a live-streamed press briefing. The study recruited approximately 2,000 volunteers with a median age of 31 years. Researchers administered two doses of the AstraZeneca vaccine to half of the volunteers, and a placebo to the other half. They then assessed the vaccine’s efficacy against the B.1.351 variant.
AstraZeneca Vaccine’s Efficacy Reduced to 22%
In comparison to the original coronavirus strain, efficacy against the South African variant was described as ‘substantially reduced’. The early data revealed just a 22% protection against mild to moderate disease. But, surprisingly, none of the volunteers developed severe disease. Thus, suggesting that the vaccine may offer protection against severe infection.
Not only are the results based on small sample size, but also the study has not yet been peer-reviewed. Therefore, experts believe the data is unreliable and not clear enough to draw conclusions.
South Africa’s only approved vaccine at the moment, is AstraZeneca’s COVID-19 vaccine. It is also the cheapest and most easily distributed vaccine out of the ones currently in use across the world. To further complicate matters, South Africa’s decision comes just a week after the country received 1 million doses of the vaccine.
South Africa Scrambles for New Vaccine Plan
Now, the country is looking for an alternate vaccine strategy as it works to contain the spread of the virus in the region. According to the country’s health minister, Dr. Zweli Mkhize, they plan to administer vaccines made by Pfizer/BioNTech and Johnson & Johnson. Results from Johnson & Johnson’s phase 3 trials had revealed a vaccine efficacy of 57% against severe disease due to the B.1.351 variant.
Experts are also considering mixing doses of AstraZeneca with another vaccine. An experimental study testing a combination of AstraZeneca and Pfizer vaccine is currently underway in Britain.
The University of Oxford, along with its partners, has already started working on a vaccine against the new variant. This will allow the vaccine to adapt to the emerging strains.
We are working with AstraZeneca to optimize 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.
Sarah Gilbert, Professor of Vaccinology at the University of Oxford
Reference:
University of the Witwatersrand
