Covid shot seen as likely universal booster
US biotech billionaire Patrick Soon-Shiong is backing a Covid19 vaccine candidate that he sees as having potential as a universal booster of other pandemic shots.
ImmunityBio Inc, of which the
68-year-old holds about 13 per cent, is developing a vaccine called hAd5 that's intended to specifically activate T-cells that scientists believe are a key part of the immune response against Covid. This quarter, the South African-born biotech tycoon will begin trials in that country, the scene of what he calls a Covid-19 "firestorm."
Most vaccines work to elicit immune proteins called antibodies blocking the spike protein that the coronavirus uses to enter cells. San Diego-based
ImmunityBio is trying to raise Tcells against both the spike and another viral protein, called the nucleocapsid, Soon-Shiong said. This could make it ideal for use as a booster for different types of vaccines, he said in an interview.
"The concern we've had with regard to just antibody-based vaccines is that it's not going to be sufficient," Soon-Shiong said. "You really need the combination of an antibody and a T-cell-based vaccine."
Beset by the highly transmissible delta variant, South Africa has been battling its most intense Covid wave. While vaccinations there have recently gathered pace, the continent is still the world's least-vaccinated with just 1.4 per cent of its 1.2 billion people fully immunised. That's raising fears about the emergence of new, more deadly coronavirus variants that could undermine the efficacy of current vaccines.
ImmunityBio's study is the first to try boosting levels of both antibodies and T-cells against the nucleocapsid, part of the core of the virus. The company's South Africa Sisonke T-Cell Universal Boost trial will enrol some of the 485,000 health workers who have already received Johnson & Johnson's single-dose Covid shot. The results of vaccination with ImmunityBio's shot will be compared with people who received only J&J's, SoonShiong said. The company is also planning studies in the US.
The goal of the shot is to produce "potent T-cells so you can kill the factory that is making the virus," Soon-Shiong said, and "help overcome this challenge of mutations that happens continuously."
Some scientists are concerned about the backbone of ImmunityBio's shot, called Ad5, which was used in a failed Merck & Co's HIV vaccine trial years ago. In that trial, people who received the vaccine were more likely to contract HIV than those who didn't, a finding that some researchers tracked back to the a virus used in the shot. Those findings weren't conclusive, Soon-Shiong said and he is confident that the ImmunityBio shot is safe.