We are genetically and immunologically unique. But that is by design because if we were all immunologically identical, we would react to the same infection in the same way and our species would die out. Even members of the same family react differently to different immune system threats. But while some people do claim never to get cold and flu-like infections and may think that they will avoid coronavirus too, the reality is we are just more susceptible to some types of infection and more resilient to others. There’s no hierarchy to this and none of us are invincible to everything.

 

Will taking vitamins and minerals help?

 

When thinking about protecting themselves and fighting infection, most people believe that taking vitamin C, in supplement form, will be helpful. It’s certainly true that vitamin C plays a key role in immunity and that a deficiency of it can lead to a higher susceptibility of a cold or virus.

 

If you eat fruit and vegetables, vitamin C is practically unavoidable in the diet. Taking more — in doses of 1-2g daily — has not been proven to ward off infections, but it might be helpful in reducing the severity and duration of them.

 

When we are ill our immune cells need almost double the amount of vitamin C they normally do to fight an infection, so consuming more of it could be beneficial in marginally reducing the length of time you are suffering by around 8 per cent in adults and 14 per cent in children, on average.

 

If you do a lot of exercise, it’s worth taking as vitamin C appears to have stronger effects on people who train hard and maintain a healthy lifestyle. In Finnish studies on marathon runners and skiers, vitamin C supplementation almost halved the duration of a cold but had little effect on the sedentary participants.

 

Do be aware that high intakes of vitamin C can cause gastrointestinal upset in some people and that, even if you do take it, it will not make you invincible.

 

Will being fighting fit help?

Physical activity is one of the best ways to prime and even rejuvenate immunity. A recent British study of male and female long-term cyclists aged 55 to 79 found that, when compared with those of twentysomething sedentary people, the older cyclists’ immune systems were far superior.

 

Keeping your muscles active releases high levels of a specific chemical called interleukin 7 (IL-7) into the blood and that helps to prevent shrinking of a gland of great importance to immunity. The thymus gland, situated in front of the heart and behind the sternum, is responsible for producing new T cells, the master controllers of the immune system.

 

It starts diminishing in size from our twenties, a process called thymus involution, but regular exercise halts this, keeping the thymus gland in healthy shape. Resistance training — lifting weights or your own body weight through press-ups, lunges and the like — is particularly beneficial in prompting the release of IL-7. But just moving throughout the day — getting up from your desk, walking at lunchtime — is more effective than sitting all day and doing a HIIT class after work.

But shouldn’t I be avoiding the gym?

Gyms tend to pack a lot of people into a confined space, probably not the best environment to seek out during the coronavirus pandemic. If you do go, take sensible precautions such as washing your hands often before and after a workout, wiping equipment with sanitisers and avoiding people who are sniffling or coughing. Your best bet is to exercise outdoors, running, walking or cycling alone or in small groups.

 

If you usually train intensely, by all means keep it up. Your body and immunity adapt to training loads and it’s only if you increase your exercise steeply that it can start to suppress the immune system. Exercise is a form of stress to the body and will produce some immune dampening responses if you go at it too hard.

 

It used to be thought that there was a window following prolonged endurance activity in which immunity was compromised as immune cells disappeared, making people more susceptible to infection. Science has since shown that this is not the case and that immune cells are just diverted to where they are needed most after hard workouts. But sensible precautions are recommended — don’t push too far or too hard and stay warm and dry when you finish.

 

Is it OK to keep drinking alcohol?

 

There are no health benefits to drinking alcohol in terms of immunity and it may actually harm our defences. One reason for this is the effect it has on our sleep, which may be poorer in quality after a few glasses of wine. Since sleep disruption is known to increase the risk of catching a cold or the flu, it stands to reason that your susceptibility to any virus might be increased.

 

How do immunosuppressive drugs affect coronavirus?


People taking this kind of medication for existing health problems are definitely more susceptible to contracting a virus because their immunity is compromised, although they would still need to come into contact with an infected person. So far, there aren’t many case studies to go on, but it could be that Covid-19 may look different and have different implications for someone taking immunosuppressive medication.

 

Since it is the immune system that produces symptoms of a virus like coughing and a fever, these people might not initially present with symptoms as severe as other people. But long-term there could be extra risk of complications from the virus if they are infected. Without a normal capacity to mount an immune response, it could mean the virus directly damages the delicate lung cells, something that is not reversible. The advice is to not stop taking medications unless instructed by your healthcare provider to do so, and if self-isolating to ensure you have plenty of your prescription.