This week’s immunity study from Imperial College London certainly makes sombre reading. The React-2 trial, which asked about 350,000 people in England to send in finger prick antibody tests from home, suggests that protective antibodies against Covid-19 wane “quite rapidly” after the first infection, according to researcher Prof Helen Ward.
In the first round of testing, in the summer, about 60 in 1,000 people had detectable antibodies. But this figure had fallen to 44 by September. It suggests that patients might be susceptible to re-infection from Covid just months after catching it the first time, and that “herd immunity” might be difficult, if impossible, to achieve. Once a vaccine is developed, elderly and vulnerable people might need to receive it at least twice a year.
Doctors note, however, that antibodies are not the only weapon in the body’s protective armour: T-cells also play a role, by killing infected cells; while B memory cells rapidly produce new antibodies once threatened with a virus.
“We can see the antibodies and we can see them declining and we know antibodies on their own are quite protective,” Prof Wendy Barclay told the BBC. “On the balance of evidence, I would say it would look as if immunity declines away at the same rate as antibodies decline away, and that this is an indication of waning immunity.”
But as grim as the news might be, there are still steps we can take now to boost our immunity:
Adequate sleep (between six and nine hours a night, according to the NHS) is the “bedrock of your immune system”, according to Dr Jenna Macciochi, an immunologist at the University of Sussex. During sleep, our bodies produce melatonin, which helps to build new immune cells. “If you’re not sleeping, no other lifestyle measure will make much difference,” she says.
Keeping to a healthy sleep schedule can be difficult in lockdown. To help, Dr Guy Meadows, founder of The Sleep School, recommends sticking to a rigorous routine, avoiding caffeine after lunch, and only drinking alcohol in moderation. If you are working from home, he adds, try a “fake commute” in which you take a 10-minute walk each morning and evening to “transition your mind from work to home time”.
A colourful, low-carbohydrate Mediterranean diet rich in fruit and vegetables will nourish your body with antioxidants and anti-inflammatory phytonutrients, helping you to fight infection, say doctors. Broccoli, red peppers, and blueberries are particularly recommended.
“Have the fruits and vegetables whole and ideally with the skin on as this contains essential fibre that feeds the healthy bugs in your digestive tract, crucial to fighting infection,” advises Dr Claire Bailey, GP and author of The 8-Week Blood Sugar Diet Recipe Book.
Moving around throughout the day strengthens your lymphatic system, which is essential to help your immune cells perform their surveillance function on unfriendly viruses. “Regular and often is the key,” says Dr Macciochi.
Vitamin D supplements reduce your risk of respiratory infection, according to an analysis of 25 studies published in the British Medical Journal in 2017. Another study, which pooled data from 16 clinical trials involving 7,400 people, found that taking vitamin D supplements reduces your risk of catching at least one respiratory infection – including influenza and pneumonia – by a third, with benefits seen within three weeks.
In contrast, there’s little evidence that Vitamin C prevents infection – but it can shorten your symptoms once you’re infected. Oranges, kiwi fruits, spinach, grapefruit, and cauliflower are useful here, as are supplements.
Drinking plenty of water is “critically important for vastly overlooked”, according to immunologist Dr Ross Walton. The NHS recommends six to eight glasses a days. Dehydration damages the mucus layer in your respiratory tract – this contains important antibodies. Tea and coffee aren’t as effective because they are diuretics (meaning they quicken the body’s expulsion of water through urine).
Read more: Don’t panic; it’s not all over for Covid immunity – here’s why