Prof Madhi: ‘Serosurvey will measure variant spread’

While government has remained tightlipped on how many South Africans have been affected by the mutation of the highly contagious Covid-19 variant 501Y.V2, leading scientist Professor Shabir Madhi said the country had to conduct a serosurvey to determine what percentage of the population was affected.

Vaccinology head at the University of the Witwatersrand and chief investigator of the Covid-19 variant 501Y.V2, Madhi, whose investigation exposed the Indian-manufactured AstraZeneca vaccine to be efficaciously weak against the new strain, said a serosurvey would come up with reliable statistics.

Madhi’s findings revealed that SA trial outcomes showed the AstraZeneca vaccine could not deal with mild and moderate disease caused by the coronavirus – only offering 22% protection for infections caused by the 501Y.V2 strain. He said the virus had mutated after about 30% of South African adults were infected with it during the first wave and then developed “some sort of immunity”.

Madhi said the vaccine could be effective locally “to high-risk groups”.

“The WHO (World Health Organisation) recommends ongoing use of the AstraZeneca vaccine – even in countries where the B.1.351 variant circulates as it’s likely to protect against severe disease. This is considering whether it is a similar vaccine as the Johnson & Johnson vaccine and induces similar immune responses.

“Unless government has secured assailant doses to immediately start vaccinating the millions of high-risk individuals it planned to vaccinate in phase two – the toss up is between using a vaccine shown to be safe and having a high probability of protecting against severe disease versus going through another possible resurgence in a few months and high-risk groups remaining unprotected from no vaccine at all.

“There is a need to do the serosurvey to see what percentage was infected in this way. We suspect it would be similar to the first, and would be the main reason why the resurgence is subsiding.”

Madhi said the AstraZeneca vaccine would probably protect against severe Covid-19 hospitalisation and death caused by the 501Y.V2 mutation of the virus.

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