Experimental vaccines that aim to provide multi-season protection are in human studies.
For decades, scientists have been trying to develop a universal vaccine that would protect people against seasonal flu for years, and also against pandemics, which emerge when viral strains completely novel to people’s immune systems start spreading. “A universal flu vaccine is often referred to as ‘The Holy Grail’ of influenza research, and like the Holy Grail, it is challenging to achieve,” Tamar Ben-Yedidia, chief scientific officer of BiondVax, whose universal flu vaccine is now in Phase 3 clinical trials, tells The Scientist in an email.
Influenza has two surface glycoproteins: hemagglutinin, which helps the virus enter host cells, and neuramidase, which helps the virus spread among cells. Hemagglutinin is commonly likened to a mushroom because it has a round head and a stalk. The highly variable head is what seasonal flu vaccines tend to generate antibodies against. The stalk, in contrast, is more conserved, and so is the target of many efforts to generate a universal flu vaccine.
BiondVax’s M-001 vaccine—the furthest along in the pipeline toward a universal flu vaccine—contains no viruses, dead or alive; rather, it is a peptide vaccine. It contains nine, highly conserved viral epitopes, those parts of an antigen recognized by the immune system, that are common to 40,000 influenza viruses listed in a National Institutes of Health database, Ben-Yedidia tells The Scientist.