PORTLAND, Maine (AP) The director of the Maine Center for Disease Control said it’s likely there are more coronavirus cases that the state doesn’t know about, but he said he’s heartened that only 5% of tests are positive.

The low percentage suggests the state is not as far behind on testing as some other states that have positive rates closer to 20%, Dr. Nirav Shah told reporters Wednesday.

“This is one of those situations where lower is better. But we know we need to expand our testing capacity,” Shah said.

The state is working to expand its testing for people infected with the new coronavirus and is exploring testing for antibodies that demonstrate a past exposure to the virus among healthy people who’ve recovered or never showed signs of illness.

Testing will factor into the Mills administration’s decision on when to begin a phased-in reopening of the state economy. No decision has been made.

For most people, the virus causes mild or moderate symptoms, such as fever and cough, that clear up in two to three weeks. For some, especially older adults and people with existing health problems, it can cause more severe illness, including pneumonia, or death.