A Seattle doctor says that people are particularly vulnerable to getting the coronavirus while sleeping — and offered some tips for protecting yourself while snoozing.

Dr. Bruce L. Davidson wrote in an op-ed for CNN that while sleeping, around half of people are prone to aspiration — or breathing in foreign objects to the airways, which can allow the virus in.

“Coronavirus infects cells below the voice box, in the airways and deep in the lungs, unlike flu viruses which start with your nose and throat,” he wrote. “Other than via tiny particles inhaled in air, coronavirus reaches those cells via fluid in the nose or throat that sneaks past your voice box (this is called aspiration) and slides down your windpipe, or trachea.”

But Davidson — an expert in respiratory transmission of infection — said there are several steps that people can take to limit their exposure to the bug as they sleep.

First, he advises thoroughly washing your hands and face in case you have already been exposed to germs.

“Wash your hands and face well with soap and warm water, including — on a finger — a quarter-inch into each nostril,” he said. “Then gently blow your nose.”

He also suggested that people limit any sedatives, such as alcohol, before they sleep since it can increase aspiration.

Most importantly, Davidson said people should make sure that any devices they use to sleep are clean.

“The key is to minimize the virus burden around and inside your face before you go to sleep… If you use a device at night for sleep apnea, make sure it remains away from where people could cough, sneeze and breathe on it, and clean it regularly,” he wrote.

The coronavirus is a respiratory illness, meaning that it spreads through droplets launched when an infected person sneezes or coughs.

So far, the virus has infected more than 152,000 people across the world in at least 144 countries.