Maine still wants people without symptoms to get tested if they’ve been exposed to someone with the coronavirus, the state’s top public health official said Thursday.

The message from Nirav Shah, director of the Maine Center for Disease Control and Prevention, came days after the U.S. CDC removed a recommendation from its website that asymptomatic people seek testing if they’ve been exposed to the virus. The change raised alarm among public health experts, as research has shown that infected people without symptoms are responsible for transmitting up to half of cases.

The federal agency previously advised local health departments to test people who have been within 6 feet of an infected person for more than 15 minutes. But on Monday a CDC testing overview page was changed to say that testing is no longer recommended for symptom-free people who were in close contact situations.

Shah on Thursday noted that the U.S. CDC still defers to the testing recommendations of individual health care providers and state health officials. In Maine, officials still recommend testing for those who have been exposed to the virus, even if they’re not showing symptoms.

The state’s standing order that allows certain people to get tested without a doctor’s order covers those who have been exposed to the virus, whether they’re showing symptoms or not.

“The way that we have been doing this, the policy that we have adopted now for many months, is what is best for public health,” Shah said.

Maine on Thursday announced that another expansion of its state laboratory testing capacity was ready, with a new mobile laboratory at the site of the Maine CDC’s existing Health and Environmental Testing Laboratory now up and running.

The mobile lab, which the state deployed as part of its testing partnership with Westbrook-based IDEXX, will expand the state’s test processing capacity to 25,000 tests per week from 6,000. The state’s test processing capacity is supplemented by testing performed by private labs run by hospitals and other organizations.

The state announced the mobile testing lab addition in early June, with an expectation that it would be up and running last month.

The state has still seen its testing capacity rise without the mobile lab, with the state’s test volume growing by 44 percent over the past week, Shah said. The percentage of positive tests has remained low in that time, with the state posting a 0.69 percent positivity rate, he said. College campuses have been ramping up their testing over the past week as students have returned to campus for the fall semester.

A low positivity rate is a sign that health care providers are casting a wide net of people to test, and that virus transmission in the state is low. By comparison, the nationwide average test positivity rate for the past seven days was 5.9 percent as of Wednesday, according to the Johns Hopkins University Coronavirus Resource Center.

The Associated Press contributed to this report.