Can vaccines keep up with coronavirus mutations? Bay Area variant will be a test - San Francisco Chronicle

But in many ways the race has intensified in recent weeks: between a virus that is spinning out new mutations that could make it harder to contain and an immunization campaign marked by repeated fumbles.

The highly infectious B117 variant that’s spreading widely in the United Kingdom has been identified in Southern California, but only in a few dozen cases.

But the Centers for Disease Control and Prevention warned last week that the variant could become the dominant version of the virus in the U.S.

The L452R variant, whose presence in California was announced Sunday, appears to have a foothold in parts of the state and has been tied to multiple large outbreaks in Santa Clara County, but scientists don’t know for sure that it’s more infectious than the virus type that has circulated in California to date.

If L452R turns out to be more infectious, it’s unclear how the competition between it and the B117 variant would play out.

The B117 variant is not able to evade vaccines, but scientists don’t know about the L452R variant.

Some make the virus less likely to survive.

The B117 variant has 23 mutations and is much more infectious than its parent.

The L452R variant has five mutations.

That’s likely due in part to simple math — there is so much virus circulating around the world right now that even at a slow mutation rate, the alterations are going to pile up.

The good news is that the vaccines being used now can be easily modified to match a new variant, infectious disease experts said.

The possibility of a variant evading the vaccines could become more pronounced as more people are immunized, infectious disease experts say.

Random mutations that let the virus escape the vaccine will be favored — and more likely to replicate.

That also means that a clumsy vaccination program that leaves large gaps in protection could make it more likely for a variant to emerge that can evade the vaccines, she said.