According to the CDC, the risk of being exposed to the coronavirus (COVID-19) for most people is low. The CDC recommends taking simple, everyday steps to avoid catching or spreading respiratory diseases including COVID-19. These include covering your cough or sneeze and thoroughly washing or sanitizing your hands. Call your doctor and stay home if you are sick. Get more information at CDC.gov/coronavirus or contact the Tennessee Department of Health coronavirus information line at 877-857-2945 from 10 a.m. to 10 p.m. daily.

State health officials announced another infection of novel coronavirus has been detected in a Middle Tennessee woman, bringing the statewide total to four.

While the first two coronavirus cases are believed to be linked to travel, officials said Monday they hadn't yet determined if the third and fourth cases were the result of travel or the virus being transferred from someone else in the state. Tennessee hasn't yet confirmed a case of "community spread," a milestone in an outbreak.

“We can assure you we are working around the clock," said state epidemiologist Dr. John Dunn. "And we are identifying that nexus of activity and contacts and so forth, but that is an active, ongoing process at this point."

The Tennessee Department of Health said the fourth patient was an adult woman in Middle Tennessee, but released significantly less information about this new patient than they have for other cases.

Coronavirus impact in Tennessee:Latest news and updates as virus affects state

Health Commissioner Lisa Piercey said the new case was "isolated" but did not specify if she was quarantined at home or hospitalized. In a change from past cases, Piercey said the state would no longer identify the counties in which coronavirus infections are detected, unless the cases are in metropolitan areas, out of fear of outing patients.

"Fully acknowledge and understand that everybody wants to know the county,” Piercey said. “But we also have to keep in mind that we’re talking about patients here.

"Patient privacy is very important to us. While it might be easy to blend in a very large community with several hundred thousand people, when we have counties that are very small and rural, the risk of re-identification is very high.”

Previously, officials have been more transparent about new coronavirus cases.

Last week, state health officials revealed the first case was a Williamson County man who had recently traveled to Boston and was in quarantine at home. On Sunday, city officials in Davidson and Shelby counties said the second and third cases were a woman in Nashville, also isolated at home, and a patient hospitalized in Memphis.

Piercey said Monday that all four patients were "being taken care of" in conjunction with local health departments.

"They're all appropriately isolated and they're all aware of their diagnosis," she said.

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Piercey made this announcement Monday at the first meeting of the a coronavirus task force, formed by the governor last week, that included health experts but also HCA, FedEx, Amazon, the Tennessee Hospital Association and the Tennessee AARP.

Piercey told the task force the state had increased its testing capacity. As of Monday, the state had tested 49 people for coronavirus and had doubled its capacity to test more — from 85 last week to 165 people as of Monday.

Health officials also stressed that testing at private labs and hospitals would start soon, lifting some of the pressure off of government labs.

“The game is about to change for testing,” Piercey said. “We will, very soon, imminently, move from not only state health lab testing but also commercial availability. The state lab will continue to test, but the capacity will be significantly expanded given this commercialization.”

'Batman Building' partially closed for coronavirus cleaning

The spread of the virus also prompted partial closures of one of Nashville’s most prominent skyscrapers on Monday. The AT&T building, colloquially known as the “Batman Building” for its ear-like pointed towers, closed partially for a “thorough cleaning” in response to concerns about the virus, according to a flyer taped to its doors. Cleaning staff and security guards could be seen in an otherwise empty lobby.

Stephen Kulinski, managing director of CBRE Property Management, which oversees the office tower, said the building was never fully closed on Monday, but that portions of it were closed so they could be cleaned with an anti-viral solution. People who worked in the building were still allowed to come inside, but some employers told their workers to stay home.

Kulinski said the building should resume normal operations on Tuesday, but some business tenants may still tell their employees to stay home as a precaution.

Kulinski said the cleaning occurred because the Metro Public Health Department told him that one of the people who has tested positive for coronavirus worked in the building.

Novel coronavirus, or COVID-19, is a viral infection that began in Wuhan, China, but has since spread worldwide. According to the World Health Organization, more than 105,000 people and killed about 3,600 across more than 100 countries. In the United States, more than 500 cases and 22 deaths have been reported.

Coronavirus testing to begin at private labs, co-pays to be waived

Testing for coronavirus is largely being handled by government laboratories. As the virus becomes more widespread in the U.S., tests are expected to become commercially available to hospitals and private laboratories.

It is unlikely the general public will be able to buy tests themselves, but a commercial supply will make tests more available as demand increases.

Tennessee Insurance Commissioner Hodgen Mainda said three private lab companies — LabCorps, Quest Diagnostics, and AEL — would begin private coronavirus testing as early as Monday afternoon.

Mainda also requested that insurance companies in Tennessee waive co-pays and fully cover coronavirus testing so that the cost would “never be a barrier to patients who think they have symptoms.” Most of the major insurers in the state have agreed to do so, including BlueCross and BlueShield of Tennessee, which covers about 70% of the private insurance market.

“We are committed to helping slow the spread and impact of this new coronavirus,” Dr. Andrea D. Willis, a BlueCross senior vice president, said in a news release. “If a BlueCross member needs to get tested, we don’t want them to worry about the cost.”

Other insurers who have agreed to fully cover tests include CVS Aetna and Cigna.

Meanwhile, Rep. John Mark Windle, D-Livingston, filed legislation on Thursday that would "authorize" Gov. Bill Lee to enter immediate negotiations with the federal government to extend primary care for coronavirus treatment and prevention to all uninsured residents of the state.

HB 2915, which doesn't currently have a Senate sponsor, would require lawmakers to suspend rules in the legislature to hear the bill since it was not introduced ahead of the bill filing deadline.

Natalie Allison contributed to this report.

Brett Kelman is the health care reporter for The Tennessean. He can be reached at 615-259-8287 or at brett.kelman@tennessean.com. Follow him on Twitter at @brettkelman.