While vaccine makers are working to target new variants of Covid-19, scientists are looking further ahead and looking for a universal coronavirus vaccine capable of attacking future strains or even preventing another pandemic.
A mutant virus
Since the quest for a first anti-Covid vaccine boosted a new generation of serums, a great deal of work has sought to develop pan-coronavirus immunity, with varying levels of ambition.
Drew Weissman of the University of Pennsylvania, one of the pioneers of messenger RNA technology used in Pfizer's vaccine, is leading one such project.
In his eyes, the adaptation of existing vaccines to all existing strains – Pfizer announced a plan to this effect a few weeks ago – has a major limit: “new variants will appear every three or six months”.
However, after more than two years of trying to infect more and more humans, the virus is beginning to mutate specifically to circumvent the immunity acquired through vaccines - in the same way as the constant mutations of the flu, which require a serum changed every year, he explains.
“It complicates things a bit, because now we are fighting head-on with the virus”, sums up Drew Weissman.
A universal vaccine
His team is therefore working on a universal anti-coronavirus vaccine.
She is trying to find “very well-preserved epitope (antigenic determinant) sequences” – whole fragments of virus that cannot mutate easily because the virus would die without them.
Covid-19 is not the first coronavirus to jump from animals to humans in this century: its oldest relative, SARS, killed nearly 800 people in 2002-2004, and MERS-CoV (Respiratory Syndrome Coronavirus from the Middle East) followed in 2012. When the American biotech VBI Vaccines announced its pan coronavirus project on the first day of the pandemic, in March 2020, it was targeting these three coronaviruses.
If one imagined each antigen of their vaccine as a primary color, these researchers hoped that their vaccine would provide antibodies not only for these colors but also for "the different shades of orange, green and purple found between these colors" , describes Francisco Diaz-Mitoma, chief medical officer of VBI.
" One step forward "
VBI's vaccine tests have shown promise so far – including in bats and pangolins, and the biotech hopes to start clinical studies in the coming months for results in early 2023.
Another project, using ferritin nanoparticles, led by Barton Haynes, director of the Institute for Human Vaccines at Duke University in the United States, has received funding from the National Institute of Allergy and Infectious Diseases.
This vaccine, which targets SARS-like viruses but not a wider range of MERS-like coronaviruses, has been shown to be effective against Omicron, according to Barton Haynes.
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