How would this synthetic vaccine be easier to make than the traditional variety, which is grown in chicken eggs?
We would only provide the conserved stalk—or the conserved portion—of the virus's hemagglutinin. And that preparation can be made synthetically by a peptide only about 60 amino acids long. And that, given to a mouse, induces this cross-reactive immunoresponse.
Since flu strains are so good at mutating, is there a chance that they could evolve to get around this sort of vaccine?
The stem—the stalk region—is probably less tolerant to those changes. Never say never, of course, but by virtue of having seen that these regions don't change over 50 or 80 years—of course, I'm exaggerating here, in essence they have not changed—suggests that the virus has not been able to change there. So there is some hope that the virus is not so able to overcome the vaccine.
Right now, worldwide, probably only 5 percent of old people take the influenza vaccine, so it is unlikely that this mutation would happen very fast. So it's a bit like antibiotics: Only if you have excessive use of antibiotics, does resistance become a major problem.
Could a universal vaccine then protect against a pandemic, such as an H1N1 or even H5N1 spread?
They should protect against it. We would provide a herd immunity against every single strain conceivable. It's not 100 percent, but it would certainly dampen any impact a new pandemic strain would have in terms of morbidity and mortality—meaning disease as well as death.
Could these findings be applied to other viruses and vaccines?
Many viruses do not undergo this change, so for those kinds of vaccines there's no need for change because they work very well. There are, however, celebrated cases, such as HIV and hepatitis C, which also undergo a lot of change. The idea of finding conserved domains and using those in vaccines has been around. It just hasn't worked. A similar approach to those two viruses is always possible if one can identify the conserved regions. We can't use a conserved region of the influenza virus to protect against HIV or hepatitis C.
So where is the research now? When might we expect to see a universal flu vaccine?
We only showed it in mice, so one has to extend this to other animal models—the ferret and the guinea pig. And only if those experiments would be successfully completed would we think of going into humans.
It is always much easier to protect mice. You know this from cancer—you can cure cancer in mice, but in humans, it ain't so easy. One has to see if that same approach would also be effective in humans.
We can, for the first time, think about a universal influenza vaccine. Clearly our approach is just the beginning.