Vaccine Rollout Races Against Evolving Virus Variants

The race is on between COVID-19 vaccinations and the continuing evolution of coronavirus variants that threaten to undermine them.

As vaccination ramps up in the United States and cases decline, people are letting their guard down, including those who are not vaccinated. But public health experts are urging people not to let loose just yet. The virus is not done evolving, they note. Some variants have already emerged with traits that weaken the protection the vaccines provide against the virus. The more it spreads, the more chances it has to get better at ducking the vaccines' defenses.