Thursday May 13th 2021
Work on T-cell vaccine
Corona super vaccine should protect for years
The rapid development of vaccines against corona is a miracle of medicine, the mRNA process is a small revolution. But all available vaccines must be refreshed regularly – and do not always work against mutations. A different method aims to solve both problems – but carries other risks.
How long does the corona vaccination work? This is one of the great unknowns in the pandemic. The fear is that the vaccine protection of the vaccines currently used decreases over time and could be ineffective or at least less effective against virus variants. Several startups are therefore working on a vaccine that should make people immune to new mutants over the years.
Presumably a booster vaccination is necessary every year in order to extend the protection of the vaccination and to ward off new variants, the head of the US pharmaceutical giant Pfizer, Albert Bourla, recently admitted. The vaccines approved to date are primarily intended to stimulate the formation of antibodies that recognize and destroy the virus before it infects a cell.
Some young biotechnology companies are taking a different path. With their vaccines, they are trying to stimulate T cells in particular – that part of the immune response that focuses on finding and eliminating cells that are already infected, not the virus itself. That does not mean that the previous vaccines have none To produce T cell responses, this is not their primary goal.
First research results mostly encouraging
T cells have several advantages over antibodies in theory. They can survive longer in the body and react to components of the virus that are less likely to mutate than those recognized by antibodies.
In France this is the approach taken by OSE Immunotherapeutics. The biotech company has just started testing its vaccine in clinical trials. “It could protect for several years,” says CEO Alexis Peyroles. Another French company, Osivax, based in Lyon, is also working on a T-cell vaccine and promising a “universal” vaccine that would be effective against any possible variant. The government in Paris is supporting research with sums of millions.
Of the 400 vaccine developments listed by the World Health Organization (WHO), only a few are aimed at achieving universal effectiveness. The T-cell vaccine from the US company ImmunityBio is the most advanced of this type of project. First preliminary results released last month are largely encouraging.
“Can cause virus to evade vaccination protection”
The new vaccines should be ready for use next year at the earliest. Many scientists view T-cell vaccines with skepticism. “The mass vaccination itself creates an evolutionary selection pressure,” says the British virologist Julian Tang. “And this pressure can cause the virus to develop in such a way that it escapes any vaccination protection.” Vaccines designed for very widespread use could therefore be a “double-edged sword”.
Another question is whether the body will be able to fight the virus with a T cell-based response. T cells and antibodies work together to create an immune response in the body. If the antibodies fail, “the T cells are of little use,” says French virologist Yves Gaudin. He has “doubts about the effectiveness of such a vaccine”. An ideal vaccine would be effective on both levels, says the scientist.
In Europe and the United States, T-cell vaccines, if approved, could be given to people who have already received an antibody vaccine. The novel vaccines could also protect people who have difficulties producing antibodies due to diseases such as diabetes or cancer.
The OSE vaccine is a way to boost current vaccinations, says CEO Peyroles. “It would complement and broaden the response produced by the first vaccines.” However, there is still a lot of work to do for companies like OSE to achieve this goal.