CAPE TOWN (BLOOMBERG) - ImmunityBio's hAd5 T-cell Covid-19 vaccine candidate is being considered as a booster shot in a study of almost 500,000 South African health workers who have received Johnson & Johnson's inoculation.

The health workers, the first people outside of much smaller studies to be vaccinated in South Africa, will need a booster, said Dr Glenda Gray, the co-lead of the South African studies, in an interview on Wednesday (May 19).

"It could be the universal boost that we are looking for," she said.

"Hopefully, we will start in a couple of weeks."

The hAd5 T-cell kills infected cells and in addition to the spike proteins found on the coronavirus, the shot targets the nucleocapsid protein, which is less prone to mutations.

That could make it more effective against strains such as the one first found in South Africa in late 2020, ImmunityBio said in a statement earlier this year.

ImmunityBio's vaccine is in phase one trials in Cape Town, and the company has signed an agreement with South Africa's BioVac Institute to produce the inoculation in the country should it win approval.

A broader roll-out of Covid-19 vaccines began in South Africa this week.