Suffolk’s Sentara Obici Hospital and Bon Secours Health Center at Harbour View are among area hospitals and health care systems strongly recommending all patients and visitors wear medical masks upon entry.

The policy, which went into effect Tuesday, is designed to protect patients, visitors and medical staff from the spread of flu, a joint news release says.

Seasonal flu cases in Virginia have become widespread, the health systems and hospitals say, and as vaccinations are not 100-percent effective, those who have had them are urged to also comply.

“Medical evidence suggests infected persons can transmit the virus as much as 24 hours before displaying symptoms,” the health systems and hospitals say. “This recommendation will help protect patients, visitors, and staff from exposure to flu, even before symptoms occur.

“Our goal as health care providers is to use every available and appropriate measure to protect the community, our patients, visitors, family members, and staff at medical facilities from exposure to outside infections.”

Masks and hand sanitizer will be provided for public use at most entrances, and individuals displaying symptoms of influenza-like illness are asked not to visit patients at area hospitals.

Symptoms of flu include: fever and respiratory illness such as cough, sore throat, runny or stuffy nose, muscle aches, chills, and sometimes vomiting and diarrhea.

The mask recommendation will remain in effect throughout the flu season, the officials said.

Health system and hospitals say they could consider other safety measures to prevent flue spreading as the season continues.