It’s still unclear how successful a vaccine against SARS-CoV-2, the virus that causes Covid-19, can be.
A lot will depend on how the virus mutates. Broadly, there are two ways mutations can play out.
Scenario 1: The coronavirus is unable to evade a vaccine…
Vaccines work by prompting the body to develop antibodies, which neutralize the virus by binding to it in a very specific way. Scientists are watching to see if mutations will affect this interaction. If they don’t, then there is hope that a vaccine won’t need constant updating.
That same process has played out with our most effective vaccines, including the one against measles.
Scenario 2: Mutations make vaccines less effective over time
But what if the virus doesn’t get cornered like measles? If the virus mutates in a way that prevents antibodies from binding, it could make a lasting, universal vaccine difficult to create.
“What will happen in many viruses is you’ll get infected by Strain A; your immune system learns to recognize that surface protein, but then the virus is able to mutate in such a fashion that it still performs its function but make it so that your antibodies against Strain A no longer recognize Strain B,” Dr. [Trevor] Bedford said.
Versions of the virus with mutations that get around the population’s immunity are more likely to spread, and can then develop into new strains.
The takeaway: We’ll have to wait and see