A small clinical study has found that the COVID-19 vaccine developed by AstraZeneca and the University of Oxford offers as little as ten percent protection against the virus' variant first detected in South Africa.

Professor Shabir Madhi from the University of the Witwatersrand in Johannesburg, who led the trial, told BBC Radio on Monday that even if the study was conducted on a larger scale, the vaccine's efficacy would fall short of reaching 40 or 50 percent.

Madhi said the researchers had sought to determine whether the vaccine had at least 60 percent efficacy against new strains to any degree of severity.

The study found that the vaccine showed very little protection against mild to moderate infections of the South African variant in a relatively young age group with very low prevalence of health conditions such as hypertension and diabetes.

Madhi, however, said the vaccine's effectiveness against serious infection could possibly be inferred based on the Johnson and Johnson vaccine, which uses "similar technology."

South Africa, meanwhile, has halted the rollout of the AstraZeneca vaccine, while the British health minister suggested that annual vaccinations could become the norm.