Reopening indoor restaurants is "an extraordinarily reckless and premature decision" as new, more contagious variants of the coronavirus spread across the US, virologist Angela Rasmussen told CNBC on Friday.
Indoor dining resumed on Friday in New York and Portland, Oregon with limited capacity.
"While I appreciate the economic importance of reopening businesses and cases are on the decline, there are new flavors that are more transferable," Rasmussen said on CNBC's The News with Shepard Smith.
Rasmussen, a virologist at Georgetown University's Center for Global Health Science and Security, said the UK eased Covid restrictions in early December. Cases then emerged after a new, communicable strain of coronavirus was identified.
New, more contagious strains of coronavirus originating in the UK, South Africa and Brazil have spread to the US.
The strain, first identified in the UK, doubles its range in the US approximately every 10 days. This is evident from a study published by researchers on Sunday.
"We don't need to create new ways for the virus to spread among strangers who don't belong to each other's household groups," Rasmussen said.
Indoor dining increases a person's risk for coronavirus infection, as per the Center for Disease Control and Prevention guidelines. The flow of ventilation in restaurants can cause aerosols to spread to distances greater than two meters. This was the result of a study published in November.
"We have to stick with the non-pharmaceutical interventions that are supposed to reduce the risk of exposure like masking and distancing, until we can get more people vaccinated," said Rasmussen.