The highly transmissible delta variant is still the dominant coronavirus strain in the United States, accounting for more than 99 percent of cases of covid-19.

Rochelle Walensky, director of the Centers for Disease Control and Prevention, has described the delta variant much differently than the strain that took hold last year, capable of generating infections even among vaccinated people, though those cases are likely to be far less severe.

“The delta variant is showing every day its willingness to outsmart us and to be an opportunist in areas where we have not shown a fortified response against it,” she has said.

The good news, Walensky has said, is that all three coronavirus vaccines available in the United States can provide strong protection against severe disease and death from covid-19, the disease caused by the virus. Preliminary data from several states over the past several months suggests that 99.5 percent of covid-19-related deaths occurred among unvaccinated people, she said. In fact, recent data released by the CDC shows that unvaccinated people were 10 times more likely to be hospitalized and 11 times more likely to die of covid-19 over the spring and summer.

“The bottom line is this: We have the scientific tools we need to turn the corner on this pandemic,” Walensky recently told reporters.

Here are answers to common questions about the delta variant and how people can help protect themselves during the pandemic.