Why the measles vaccine works for life
A new study has found the reason why measles only needs a two-dose vaccine in childhood to provide immunity for life.
The study, published in Cell Reports, has found that while influenza mutates regularly, the surface proteins the measles virus uses to enter cells are ineffective if they suffer a mutation. Therefore any changes to the virus would come at a great cost.
The researchers mutated all the genes in a virus using a high-throughput approach. They inserted the mutations across the measles genome and looked to see whether the viruses were still incapable of infection.
Unlike the influenza virus, measles could not tolerate any mutations to the proteins that are recognised by the human immune system.
Senior study author Nicholas Heaton, a microbiologist at the Icahn School of Medicine at Mount Sinai, New York said they didn’t expect such results.
“The almost complete lack of tolerance to insertional mutation of the measles proteins was surprising. We thought that they may be less tolerant than the influenza proteins, but we were surprised by the magnitude of the difference,” he said.
Heaton says they don’t yet know why the measles virus would find an evolutionary advantage to being so rigid.
“If we can better understand why flexibility or rigidity is imposed at a molecular level, we may be able to understand more about why we see different dynamics of viral evolution.”