Blood banks and donation centers could face a critical blood shortage as a result of precautions taken to stop the spread of the novel coronavirus, one blood service nonprofit warned Wednesday.

According to Vitalant, blood donation centers in the Bay Area and across the country are staring down a critical supply shortage after closures of schools and local businesses have wiped out blood drive locations.

More than a quarter of Vitalant's planned blood donation events in March have been canceled as a result of local closures.

"If you're healthy, you're needed now more than ever," Vitalant chief medical and scientific officer Dr. Ralph Vassallo said.

"We cannot let it get to the point where there's no blood available for trauma patients, those undergoing cancer treatment and patients who need regular, ongoing blood transfusions just to survive."

While federal, state and local public health officials have advised against or even banned large public gatherings, donating blood is deemed an essential health care activity and is exempt from such bans.

Blood donation centers do not test for the coronavirus and potential donors are required to be in good health. Donating blood will also have no effect on the immune system.

"We need people to start turning out in force to give blood," said Dr. Peter Marks, director of the U.S. Food and Drug Administration's Center for Biologics Evaluation and Research, which oversees blood donation centers. "We need it not to get to the point that surgeries are having to get canceled."

Blood donations can be made with Vitalant, the American Red Cross, the Stanford Blood Center and several other donation centers around the Bay Area.

All blood types are currently in demand, according to Vitalant. Type O-negative blood, the universal donor, is especially critical as surgeons and doctors use it first before they're able to confirm a patient's blood type.