This is just a specific version of the Red Queen of evolution and in no way unexpected. But the virus will keep mutating as much as it spreads, so our best bet

This is just a specific version of the Red Queen of evolution and in no way unexpected. But the virus will keep mutating as much as it spreads, so our best bet is still to vaccinate as widely as possible to contain the spread, thereby reducing chance of mutations. Vaccinated people get still sick but are less likely to infect others, reducing overall spread.