As of Wednesday, fully vaccinated residents in New York and Connecticut are no longer required to wear masks or stay 6 feet away from others in most settings, as a growing number of states follow the Centers for Disease Control and Prevention’s more relaxed mask guidelines.

But that decision is putting people at risk, warns Dr. Natasha Kathuria, an emergency medicine physician, who says there is no efficient way to verify who is vaccinated and who is not.

“We’re really depending on an honor system,” Kathuria told Yahoo Finance Live. “There’s no way to ensure that the people removing their masks are vaccinated or not.”

“We really want people to still be cautious. This is not the time to completely let your guard down while things are improving and looking great,” added Kathuria.

Many states immediately relaxed mask mandates following the CDC’s updated guidance, while others, including California, Maine and Massachusetts said they plan to rescind their face covering orders soon.

However, states still have the authority to uphold existing mask mandates if they choose and, so far, New Jersey is the only state with no plans to lift its mandate for fully vaccinated people indoors.

New Jersey Gov. Phil Murphy tweeted on Monday that the indoor mask mandate remains in place in public spaces because "the majority of New Jerseyans are still unvaccinated."

Vaccination rate slowing

The vaccination rate nationwide has slowed in recent weeks. An average of 1.8 million doses a day were administered over the past week, down from a peak of more than 4 million in early April.

As of Wednesday, more than 154 million U.S. adults, about 60% of the population, received at least one vaccine dose, according to CDC data. Meanwhile nearly 123 million Americans, about 47.6% of the population, are fully vaccinated.

The argument from health officials who say the CDC is acting too quickly is based on the fact that vaccines did not become widely available until the second half of April, so lifting the mask mandate now means that many Americans will be indoors with unvaccinated and unmasked people. That in turn will increase people’s risk of getting the virus, especially with the threat of variants.