Health workers are on the frontline of the COVID-19 pandemic and they need safeguarding, which includes giving them sufficient rest. Protecting ourselves and our loved ones against COVID-19, the new coronavirus is, understandably, our number one concern.

We’ve all heard about handwashing, but did you know that getting a good night’s sleep is also vitally important for combating the virus because it boosts your natural immunity? Numerous studies have shown a clear link between stress, poor sleep and vulnerability to viral infections.

We are seeing the tragic consequences of being overworked and sleep-deprived in the current outbreak in China and Italy, where dozens of young medical staff are getting infected and dying. People like Peng Yinhua, a 29-year-old Chinese doctor, who postponed getting married to help treat patients in Wuhan. He paid the ultimate price, dying on 21 February.

Another young doctor, Li Wenliang, the whistleblower who first alerted the world to the dangers of COVID-19, died of the infection and overwork in February, aged just 34. He left behind a son and pregnant wife.

Healthcare workers are particularly vulnerable to COVID-19 because they get more exposure to it through treating sick people, but also because they are expected, in emergency situations, to work around the clock.

In China, there were stories of medical staff wearing nappies because they didn’t have time to take a break. This is brave but very foolish. 

We know from previous outbreaks that it is the overworked and overstretched medical staff who bear the brunt.

During an outbreak of the Ebola virus in 2013, which killed more than 11,000 people in West Africa, it was healthcare workers (mainly nurses, doctors and medical students) who were most exposed. According to the World Health Organization (WHO), they are more likely to get infected than the general population.

Again, if you look at SARS (a coronavirus infection that killed one in 10), around 20 per cent of people who got SARS were medical workers.

So what is the link between sleep, stress and vulnerability to infection?

It is all to do with the way you get infected, and the way you respond. A typical COVID-19 infection begins when you inhale particles from someone who is infected, or more likely you pick some particles up on your fingers by touching a surface. If you don’t wash your hands, then the next time you now rub your eyes, the virus gets in.

The viral particles then travel to your lungs where they infect lung cells. It is like a rogue robot taking over a factory and using it to produce endless versions of itself before going off to conquer the world.

What makes viral particles so dangerous is they hijack the mechanism of those cells to make billions more copies of themselves.

The race is now on, between the virus, which will try to replicate as fast as possible, and your immune system, which will try to wipe it out before it can really take hold. The trouble is, if your body has never seen this sort of virus before, then it will take time to mount an adequate immune response and to do that it needs all the help it can get. 

That is where sleep comes in. During deep sleep your body makes cytokines, a type of protein that targets viral infections, creating and coordinating a powerful immune response.

Cytokines are both produced and released during deep sleep, causing a double whammy if you don’t get enough.

Lack of sleep (and stress) will also suppress the production of infection-fighting antibodies, which are vital for combating viruses.

A very recent study has also shown that after a night of poor sleep, your T killer cells, a vital part of your immune system whose job is to bind onto cells infected by viruses and destroy them, become less effective. Lack of sleep reduces their ability to latch onto infected cells. 

The impact that sleep has on our ability to fight viral infections was highlighted by an extraordinary study where American researchers deliberately tried to infect a large group of healthy volunteers to see how well their immune system fought back.

For this study, they asked 164 healthy men and women to wear sleep trackers and keep a record of how well they slept. They were then brought into a lab and asked to inhale nasal droplets containing cold-inducing viruses. After that, all the volunteers were kept, isolated, in a nearby hotel for another five days and constantly monitored. 

It turned out that those who slept less than six hours a night were four times more likely to develop a cold than those who got seven hours or more. In other words, not getting enough sleep made them hugely more vulnerable to the impact of the common cold virus, despite being exposed to exactly the same level of infection.

In a similar study researchers found that if your sleep efficiency (the percentage of time you spend in bed asleep) was 90 per cent or better, then you were nearly six times less likely to develop a cold than if your sleep efficiency was low. 

Make sure you are getting enough sleep, particularly if you are a healthcare worker.

I’ve no doubt that a good night’s sleep is the best possible medicine. Sleep is when the body’s immune response really kicks in and it’s one reason why fevers tend to rise at night, as fever is a sign of your body fighting back. It is also when your body makes the necessary changes which fortify your immune system to fight off infection and viruses, and recover from them too.

I hope hospitals and GP surgeries have put plans in place to ensure that healthcare workers not only get the masks, gloves and equipment they need to protect themselves against COVID-19, but also to ensure they get enough rest to keep their immune systems in really good shape for the challenges ahead.

We are facing a serious epidemic and we need our health workers more than ever. A good night’s sleep is one of our, and their, best defences.

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Dr Michael Mosley’s new book Fast Asleep investigates the recipe for a peaceful night based on groundbreaking sleep science.