A sudden about-face by the CDC earlier this week dramatically reducing the recommended time people need to quarantine after testing positive for COVID-19 has many doctors across the country concerned.

Dr. Erin Bromage is an associate professor of biology at The University of Massachusetts Dartmouth. He is worried that cutting suggested quarantine times in half won't do enough to slow the spread of the virus.

"There is no evidence to suggest at day five you are not shedding virus and in fact, there’s more evidence to suggest that you are," he said in an interview earlier this week.

On Monday, the CDC announced that an infected person should go into isolation for five days, instead of the previously recommended 10. At the end of five days, if you have no symptoms, you can leave quarantine but must wear a mask around others for another five days.

If you still have symptoms after isolating for five days, the CDC says you need to continue to stay home.

"With this, there’s no data. There’s nothing to support that shortening it to five days with no test is as safe as what we had before," Dr. Bromage added.

Dr. Bromage wanted to see some kind of rapid testing involved in the new CDC guidelines. He says a five-day quarantine, with a negative rapid test, would’ve been a much safer way to go.

"If you’ve got enough virus to be detected on the test you have enough virus to infect other people, if a rapid test is negative you should be confident in interactions with other people," Dr. Bromage said.