WASHINGTON — The U.S. Centers for Disease Control and Prevention released new return-to-work guidelines Wednesday for essential employees who have been near someone infected with COVID-19.

The recommendations are intended for essential employees and employers who are asymptomatic.

“One of the most important things we can do is keep our critical workforce working,” said Dr. Robert Redfield, head of the CDC, during a White House press briefing Wednesday.

Under the guidelines, essential employees are first responders, janitorial staff, and workers in food, agriculture, information technology, and other critical fields.

The recommendations state that employees should take their temperatures before work, always wear a face mask, and practice social distancing in the workplace. If an employee has a temperature, they should remain home until they are well.

Employers are encouraged to take the temperature of their employees before a shift, to send employees home if they become sick during the workday, and to increase the frequency of cleaning practices in the workplace.

The new guidelines come as the Trump administration touts what it sees as a leveling in the number of positive Covid-19 cases across the country.

President Donald Trump said he believes the U.S. is heading toward a “final stretch” in combating the virus.

“Hopefully, it will end soon,” he said during the briefing.

Dr. Deborah Birx, the White House’s coronavirus task force coordinator, praised Americans who have stayed at home and self-quarantined during the spread of COVID-19.

“We are still in awe of the American people’s strength in this in following through,” Birx said.

Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, has regularly expressed confidence that people who are infected once cannot become infected again, but the verdict is still out.

If the novel coronavirus acts like many other viruses, once a person is infected, heals and then sees the virus clear the body, immunity generally protects against reinfection.

But early reports from researchers at Fudan University in Shanghai released this week found that roughly a third of 175 patients discharged and surveyed from a local hospital had “unexpectedly low levels of antibodies” or no antibodies detected at all. The study has not been peer-reviewed, according to the South China Morning Post, which first reported the development.

This news from China came the day before Wuhan ended its sweeping lockdown in the city where the virus first originated. Citizens will be allowed to move more freely than before the lockdown and don’t require special permissions to do so, but the Chinese government has assigned strict surveillance programs, like applying a special code on a person’s cellphone that indicates whether they are healthy enough to travel or return to work.

Residents in Wuhan are still required to wear face masks in public.

The virus that causes COVID-19 poses a unique challenge to reintroduction measures because so many carriers are asymptomatic.

Fauci acknowledged this during a taskforce press conference this past weekend. He said his best but unscientific estimate suggests that anywhere from 25% to 50% of those who are infected are likely not showing symptoms at all.

During Wednesday’s briefing, Fauci cautioned Americans to not get “complacent” in their social distancing efforts.

“We know now for sure that the mitigation that we have been doing is having a positive effect, but you don’t see it until weeks later,” Fauci said.