In fight against COVID variants some companies target T cell jabs
Paris, France – Getting COVID vaccines into the arms of the world’s population is an international priority - but will today’s jabs stay effective against virus variants that are spreading across the globe?
It is one of the big questions about the pandemic, with Pfizer chief Albert Bourla recently acknowledging that it is likely a booster will be needed to help extend the protection conferred by its vaccine and ward off new variants.
A recent study presented a mixed picture.
It found that the antibody response of current vaccines could fail against variants. However, a second immune response in the form of killer T cells - which attack already infected cells and not the virus itself - remained largely intact. Several startups are working on developing shots centred on T cells in hopes of producing a jab that would not only provide protection against new virus strains already on the loose, but also variants that don’t yet exist.
Alexis Peyroles heads up French biotech firm OSE Immunotherapeutics, which is developing a vaccine that targets T cells that has just begun clinical trials.
“It could offer several years of protection,” he told AFP.
Another French firm, Lyon-based Osivax, is also working on a T cell shot, promising a ‘universal’ vaccine that would be effective against any potential variant.
The government of France, which has yet to develop its own vaccine, is supporting the effort with millions in funding.
Such projects are far from widespread. Among the 400 vaccines under development counted by the World Health Organization only a few are aimed at universal use.
The most advanced shot of its kind is the ImmunityBio vaccine under development in the United States. Very preliminary results released last month were mostly encouraging.
‘Complement and broaden’
No lab foresees a final product before next year and many scientists are sceptical about the usefulness of trying to develop a shot to protect against a virus strain that doesn’t yet exist. “Mass vaccination itself is a form of evolutionary ‘selection’ pressure,” British virologist Julian Tang told AFP, “And this pressure may push the virus to evolve to escape any vaccine protection - so it can be a doubleedged sword.” Other questions involve the extent to which the body will be able to fight the virus with a T cellbased response.
T cells and antibodies work together to form an immune response in the body. French virologist Yves Gaudin pointed out that if an antibody response fails, “T cells don’t serve much purpose”.
He said he is ‘doubtful about the effectiveness of such a vaccine’, emphasising that an ideal vaccine would be effective in both areas.
In Europe and the United States the plan for T cell jabs, should they see the light of day, would be to give them to people who had already received the current antibody vaccines.
Peyroles confirmed that OSE’s vaccine, should it prove effective in trials, is indeed meant as a way to strengthen current inoculations.
“You would complement and broaden the response created by the first vaccines in terms of scope and time.”
He added that T cell vaccines could offer protection to people who have difficulties developing antibodies due to other ailments such as diabetes or cancer.
New vaccine laboratories
Britain is spending £29.3mn on new coronavirus vaccine laboratories in an effort to ‘future-proof the country from the threat of new variants’, the government said on Wednesday.
The new labs at the Porton Down research facility in southwest England will be used to test the effectiveness of vaccines against variants and speed up their deployment, according to Health Secretary Matt Hancock.
“We’ve backed UK science from the very start of this pandemic and this multi-million pound funding for a state-of-the-art vaccine testing facility at Porton Down will enable us to further future-proof the country from the threat of new variants,” he said.
Porton Down is the secretive army base near Salisbury in south west England. The Defence Science and Technology Laboratory - its official name - employs 3,000 scientists across a sprawling rural site.
New funding will increase the site’s current blood testing capacity from 700 to 3,000 samples a week, enabling scientists to measure more quickly the levels of antibodies that are generated by the vaccines.
‘The expanded testing capacity at
Porton Down will ensure the UK stays one step ahead of the virus and is in the best possible position to respond to new threats from COVID-19 as quickly as possible,’ the government said. Leading scientists are still concerned that a new variant resistant to current vaccines may lead to a new surge.
“A new variant that can escape the current vaccines is the greatest risk of a third wave,” said Jenny Harries, chief executive at the UK Health Security Agency (UKHSA). “This new investment will help us stay one step ahead of the virus by doubling our capacity to test vaccine effectiveness against emerging variants.”
Meanwhile, US biotech firm Moderna announced initial data from a small clinical trial that showed its booster shots improved people’s immune responses against key coronavirus variants of concern.
“We are encouraged by these new data, which reinforce our confidence that our booster strategy should be protective against these newly detected variants,” said the company’s CEO Stephane Bancel.
Forty participants were tested for their levels of neutralising antibodies six to eight months after their primary vaccination series of two shots.
A third shot of either the original Moderna vaccine or a variant-specific booster improved antibody levels against two major variants, which were first detected in South Africa and Brazil. The variant-specific booster performed better than the original shot, producing almost twice as many neutralising antibodies.