(Bloomberg) -- Russia’s Sputnik V vaccine, CanSino Biologics Inc.’s shot and other Covid-19 immunizations relying on a cold virus that’s backfired in the past should show they don’t make people more vulnerable to HIV infection before gaining approval in South Africa, the head of a local vaccine company said.
Sputnik V, CanSino’s injection and another vaccine in development from ImmunitiBio Inc. use a harmless cold germ called adenovirus type-5 to carry the genetic material of SARS-Cov-2 into patients’ cells to trigger an immune response.
The approach caused problems more than a decade ago when an experimental AIDS vaccine from Merck & Co. that relied on the cold virus was tied to increased infections with HIV and research was halted. Any heightened susceptibility to the virus that causes AIDS is of particular concern in South Africa, which carries the world’s heaviest HIV burden with as many as 7.8 million people infected.
“It’s a concern that has to be addressed,” Morena Makhoana, the chief executive officer of Biovac, South Africa’s state vaccine company, said in an interview. Companies have been “encouraged to do a clinical trial in our setting. I don’t think it’s an issue that can’t be overcome.”
Scientists’ Warning
Scientists highlighted the risk in a letter published in the medical journal The Lancet last October, saying Covid-19 shots relying on the same vector as the Merck one “could similarly increase the risk of HIV acquisition among men who receive the vaccine” and calling for an evaluation.
Other vaccines rely on this approach -- they are known as viral-vector immunizations-- but not all of them carry the same germ. AstraZeneca Plc’s and Johnson & Johnson’s coronavirus shots uses other adenoviruses. In the case of Sputnik V, whose booster shot differs from the original injection, only the second dose uses a type-5 adenovirus as a vector.
The reason why the Merck vaccine made some recipients more prone to getting HIV was never fully elucidated, according to Makhoana. “At the moment, there is some association with Ad5 and HIV, but it doesn’t mean there is a direct link,” he said.
An adviser to the government says research is needed to show the coronavirus vaccines won’t have the same effect on the immune system -- but that doesn’t necessarily mean embarking on months of costly new trials.
“It doesn’t have to be a clinical study,” said Salim Abdool Karim, co-chair of South Africa’s Covid-19 ministerial advisory committee. “It could be a study in animals, it could be some laboratory marker.” The manufacturers, he said, must “show us that the Ad5 used in the HIV vaccine trial and their Ad5 are behaving differently.”
‘Controversial’ Findings
CanSino acknowledged the HIV background when it published early clinical results in the Lancet in May, saying the link between increased infection risk and Ad5-vectored vaccines was “controversial and its mechanism is unclear,” but that it would monitor participants preventively.
The state-run Russian Direct Investment Fund, which backed Sputnik V’s development and is in charge of its international roll-out, said there’s no confirmed connection between type-5 adenovirus-vector vaccines and HIV risk. Data from small-scale studies was later contradicted by larger analyses, a spokesman said by email.
ImmunitiBio’s experimental vaccine is due to start human clinical trials in Cape Town this month.
©2021 Bloomberg L.P.
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