The lack of Covid testing capacity in the United States could mean the new, highly transmissible coronavirus strain that first emerged in the United Kingdom is already working its way through communities across the U.S.That’s according to Dr. Nahid Bhadelia, the medical director of the Special Pathogens Unit at Boston Medical Center.”To find that strain, what we need to do is to take a percentage of the samples that are diagnosed and do deep genetic analysis, and (in) the U.S., our capacity hasn’t been spectacular,” the infectious diseases physician told “The News with Shepard Smith” on Monday. “If the strain is here, we might just be missing it because the holes in our net are too wide.”According to the Centers for Disease Control and Prevention, the new variant has not been detected in the U.S.However, the agency said viruses have only been sequenced from about 51,000 of the 17 million infections in the country. The United Kingdom has recorded the most sequences with 125,00. Infections in the U.K. hit their second-highest daily total on Christmas Eve, with the country confirming 39,036 new Covid-19 cases that day.Starting Monday, the U.S. will require all travelers flying from the U.K. to show proof of a negative Covid-19 test amid growing concerns about the new variant of the virus.Dr. Bhadelia, who is also NBC News’ medical contributor, explained that the measures didn’t go far enough. “You can still have people who were negative when they tested, and get on the plane, and turn out positive later, so that’s why I think testing needs to be linked to some sort of quarantine,” she said.Japan has taken more stringent measures and stopped all foreign national arrivals. More than a dozen countries have reported cases of the fast-spreading mutation including Canada, France, South Africa, Australia, Japan, and South Korea. Health experts in the U.K. and U.S. noted that while the new variant appears to be more transmissible, there is no evidence yet that it is more deadly. Dr. Bhadelia warned that the findings should not make people complacent when it comes to the new strain.”The troublesome thing is that even though we don’t think it increases mortality, the fact that it can be transmitted more easily is also more of a concern because the more people who get infected, the more people eventually end up in the hospitals, and potentially pass away,” she added.