AZ Vaccine6 Feb 2021 22:13
The Oxford/AstraZeneca Covid-19 vaccine does not appear to offer protection against mild and moderate disease caused by the viral variant first identified in South Africa, according to a study due to be published on Monday.
Although none of the more than 2,000 patients in the study died or was hospitalised, the findings, which have not yet been peer reviewed, could complicate the race to roll out vaccines as new strains emerge.
In both the human trials and tests on the blood of those vaccinated, the jab showed significantly reduced efficacy against the 501Y.V2 viral variant, which is dominant in South Africa, according to the randomised, double-blind study seen by the Financial Times.
“A two-dose regimen of [the vaccine] did not show protection against mild-moderate Covid-19 due to [the South African variant]”, the study says, adding that efficacy against severe Covid-19, hospitalisations and deaths was not yet determined.
The so-called Kent variant — which Oxford university said on Friday was just as susceptible to the vaccine as older variants of the virus — has now acquired the E484K mutation, which is present in the variants fuelling Covid-19 surges in Brazil and South Africa.
There are caveats to the study, as the sample sizes were relatively small. The study, led by South Africa’s University of the Witwatersrand and Oxford university, enrolled 2,026 HIV negative individuals, with a median age of 31. Half the group was given at least one dose of placebo, with the other half receiving at least one dose of vaccine.
Tulio de Oliveira, who heads the Network for Genomic Surveillance in South Africa, told the Financial Times the findings were a “wake-up call to control the virus and increase the response to Covid-19 in the world”.
Health authorities worldwide hope vaccines will reduce or completely eliminate the burden of hospitalisation, which would allow for lockdowns to be eased.
While important, it is relatively less urgent to avert symptomatic, but milder, infection that does not progress to hospitalisation.
Any setback for the efficacy of the Oxford/AstraZeneca vaccine would be particularly crucial for the developing world, as the partners are producing billions of doses on a non-profit basis during the pandemic.
The vaccine still appears to be fully effective in preventing hospitalisation and death caused by other variants of coronavirus, according to data from other studies.
AstraZeneca initially declined to comment. It later said it had not been able to properly ascertain the effect of the vaccin
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