AUSTIN (KXAN) — As one of the worst flu outbreaks in recent years continues, pharmacies say many people have rushed in to buy medical masks, in hopes that wearing one will prevent them from catching the virus.

As a result, pharmacists say there’s a nationwide shortage of masks, making it hard for them to get any from their suppliers for the past several weeks.

East Austin Medicine Shop pharmacist Chris Perling says the three big wholesalers that provide pharmacy supplies to most shops nationwide are sold out.

“Even Walgreens, CVS – same wholesaler,” Perling said. “Everything’s on back order now, so you can’t get masks or anything related to the flu for over the counter, like Zinc, Vitamin C, Emergen-C, stuff like that.”

At Baylor Scott and White’s Westlake Clinic, Dr. Myra Pena-Delgado has also seen the high demand for masks.

“I’ve actually had patients who come in to see us and ask to see if we have any flu masks,” she said.

But Dr. Pena-Delgado says wearing a mask isn’t the best strategy for someone who’s healthy to avoid catching the flu.

“It’s not 100 percent effective,” she said. “It shouldn’t replace other preventative strategies such as hand washing and the flu vaccine.”

Dr. Pena-Delgado also says while masks could protect from some airborne pathogens if you’re in close contact with someone who already has the flu, after a while, the condensation from your breath, can make the mask ineffective.

“It breaks down the protective barrier from the mask,” she said.

Dr. Pena-Delgado says masks are more effective when worn by someone who already has the virus to prevent its spread to others.

“The virus itself is transmitted through contaminated droplets in the air when an infected individual speaks, coughs or sneezes,” she said. “So by wearing the mask, you’re preventing the transmission to somebody else.”