“There is so much toxic politics around Covid that it’s constraining sensible action,” he said. “Obviously it makes sense to require proof of vaccination in various settings, but that has become a political lightning rod.”
Dr. Frieden and other experts said they feared that if the Delta variant continues to circulate, it will mutate in a way that leaves even the vaccinated vulnerable. That already seems to be happening elsewhere in the world; even countries like South Korea and Israel, where the virus seemed to be in check, have new clusters of disease.
“Compared to many other countries, we are in a much more secure situation,” said Dr. Jennifer Nuzzo, an epidemiologist at Johns Hopkins University. But, she added, “I really do worry that as America enjoys its freedoms, we forget about the rest of the world, and that could come back to bite us.”
When Mr. Biden announced his July 4 vaccination goal in early May, he said meeting it would demonstrate that the United States had taken “a serious step toward a return to normal.” For many people, that seems to be the case. The president said then that Americans would be able to gather in backyards for small Independence Day barbecues; his gathering of 1,000 guests is partly aimed at showing the country that his administration has exceeded expectations even if vaccinations have stalled.
While Mr. Biden has repeatedly spoken of “independence from the virus,” Dr. Arthur L. Caplan, the director of NYU Langone Medical Center’s medical ethics division, said the president should be careful about the language he uses.
“Before I went out and had my fireworks and sipped piña coladas on the White House veranda, I would say, ‘I’ve got to make clear, as president, we have major challenges unresolved,’” Dr. Caplan said. “I would say, ‘We’re doing well at halftime.’”
Dr. Anthony S. Fauci, the president’s top medical adviser for the pandemic, said there was nothing contradictory about the administration’s message.