How to prevent the flu

The time has come for me to dedicate some time to the Coronavirus – mainly, how we can go about avoiding infection, and what steps we can take to ensure swift and healthy recovery.

In addition to following self-isolation measures set out by the government, practising proper hand-washing and seeking proper medical care if you develop symptoms, there is a lot more we can do to boost our defences during this critical time.

Traditional medicine also equips us with basic, logical strategies for treating fever and dry cough, and supporting immune function before and after viral respiratory infection.
I’ll be covering all these topics in a series of articles on COVID-19 on my blog and for the Algarve Resident over the coming weeks – for now, let’s have a look at some of the established facts about this illness.

COVID-19: How dangerous is it?
The novel Coronavirus is a relative of the common cold and other more dangerous viruses like SARS and MERS. Mortality from SARS is almost 10%, whereas the Wuhan coronavirus currently carries a death rate of 2%.

Around 14% will have severe disease when contracting COVID-19, with 6% needing intensive care. This means that at least 80% of the population will experience mild-moderate disease, including non-pneumonia and pneumonia cases, and recover without complications (1).

Those at a greater risk are older adults (65+) and people with pre-existing medical conditions. Children are not at risk – we don’t know exactly why, but we’re all pretty pleased about it.

Symptoms to look out for are fever, dry cough and shortness of breath. Others can include fatigue, muscle or joint aches and pains, sore throat, and headache – all normal flu-type symptoms. Nausea or vomiting has been reported in 5% of patients.

As we’ve been told, it spreads both by respiratory droplets and ‘fomites’ – touching a surface with the virus on it and then touching your face – but respiratory transmission is much more common.

The virus has an incubation period of 2-14 days, and the full duration of illness can be anything up to three weeks. It is absolutely essential to stay in bed – i.e. rest as much as possible – for the full duration of the disease to ensure proper recovery.

Boosting your defences
It’s very possible to contract a mild form of COVID-19 and not even realise you have it. You may just assume you have the common cold or a mild flu – although anyone who starts coughing and sneezing at the moment is bound to experience some degree of anxiety.

However, certain nutritional deficiencies in an individual can result in them having either a suboptimal or excessive inflammatory response to infection. There are also a few easy things you can do each day, along with proper hand washing, to enhance your immune response and stay as healthy as possible. Let’s go through each of these, starting with perhaps the most important: vitamin D.

Vitamin D and influenza
It was discovered in 2004 that vitamin D is essential for the production of immuno-competence proteins in the immune cells of the respiratory tract. It has an immuno-modulating action, preventing ‘cytokine storms’ – a phenomenon by which a strong immune response to influenza in a healthy individual can lead to organ damage and even death.

Vitamin D deficiency (known as rickets and osteomalacia in the worst cases) has been directly related to increased viral and bacterial respiratory infections. What’s more, the incidence of seasonal influenza correlates with the exact time period in which vitamin D exposure is at its lowest – during the winter months.

SARS followed this pattern in 2002, peaking in Southern China from February to April, where the sunlight is at its lowest. COVID-19 seems to be following the same pattern.

In light of this, taking a good vitamin D supplement at around 4000-7000 IU per day may be the most important thing you can do to prevent you and your families from getting the Coronavirus.

Just because we live in the Algarve, it doesn’t mean that we have enough vitamin D – deficiency is incredibly common amongst my patients and, while they may be a small group, this is reflected in the wider population. Two recent studies from the University of Porto showed widespread vitamin D deficiency in both older adults (65+, precisely the age bracket at the highest risk of complications from COVID-19) and teenagers.

Finally, heroic doses of vitamin D (300,000 IU) have long been used as a treatment for rickets and given to Scandinavian adults at the beginning of winter with no adverse effects. Vitamin D has been shown to stimulate the production of antiviral proteins and suppress cytokine production – so if you are exposed to COVID-19, taking pharmacological doses of vitamin D may help treat the infection.

Therapeutic doses of vitamin D are 1000-2000 IU per kilogram of body weight per day for several days – in other words 75,000 to 150,000 IU/day for several days in a 75kg individual.

Omega-3 and other micronutrients
Essential fatty acid deficiencies are also incredibly common in otherwise healthy individuals. Western diets are naturally higher in omega-6 and lower in omega-3, which comes from oily fish, walnuts, linseeds, seaweeds and algae.

Omega-3 fatty acids form part of the cellular membrane and are, therefore, closely involved in cellular function – they are also highly anti-inflammatory and have several specific immunomodulatory effects on different cells of the immune system. For example, they enhance ‘phagocytosis’ by macrophages – the process by which specific white blood cells engulf and eliminate foreign pathogens.

Some signs of omega-3 deficiency include poor memory and brain function, dry skin or dry eyes, mood swings and lack of energy. Even without these symptoms, I am recommending that my patients take 3000mg per day of a high-quality fish or algal oil supplement to boost their defences during this time.

Other critical nutrients include zinc (25mg), vitamin C (500-1000 mg), vitamin E (100-200 IU) and selenium (200mcg).

Getting enough sleep
We all know sleep is important for a healthy immune system. But just how crucial is it? In one 2002 study, 14 young adult males had their sleep restricted to four hours per night for six nights, while the control group enjoyed 7.5-8.5 hours of sleep. All subjects received an influenza immunization after day four of the trial – the trial group then rested in bed for 12 hours a night for a further seven days. At day 14, anti-influenza IgG antibodies were only 50% in the sleep deprivation group vs. the control group, despite having had a full week of deep recovery.

For new mums and dads, 7.5-8.5 hours of sleep a night may seem like a party you’ll never be invited to. I get it. Just get as much rest as you can, and make sure you’ve covered all other possible bases to bolster your defences.

Sweating it out
There is logic in the old-fashioned practice of ‘sweating a fever out’. A clinical report from Hong Kong in 2003 suggested that the SARS coronavirus is sensitive to human body temperature – if body temperature is below 36ºC, the virus grows rapidly, whereas above 37ºC the virus is attenuated or killed, and the patient has a milder inflammatory response and recovery.

The paper suggested that not only can patients with a high fever kill the virus (that means no paracetamol), but that exercising, taking baths and spending time in saunas may be of benefit.

If you don’t have a bathtub, a hot shower will do – and you might like to make yourself some smudge for your shower. The ancient practice of herbal ‘smudging’ effectively disinfects the air and may help disinfect the mucous membranes too.

Commonsense diet
It’s not difficult to imagine which foods we should be consuming more of, and which we should be avoiding in order to optimise our immune response to infection. Basically, avoid any known food allergens, sugar and alcohol, and eat plenty of fruits and vegetables for their rich fibre content. I’ve written all about the benefits of fibre on the gut microbiome and, therefore, the immune system already.

Other foods to enjoy include immunomodulating shiitake mushrooms, plenty of garlic, and fermented foods for their probiotic benefits. Common kitchen herbs like sage and ginger also possess remarkable antiviral activity.

Herbal treatment for influenza
At this time, no one outside of China has any direct experience treating COVID-19 infection with herbs. However, it would appear that the infection may be treated with the same approach used for influenza and other respiratory infections – and this approach is consistent with efforts in China.

Next: all about herbal treatment for influenza… until then, stay safe!

By Poppy Burr
|| [email protected]

Poppy is a UK-trained medical herbalist practising in Praia da Luz. She offers consultations and treatment in Western Herbal Medicine, incorporating Functional Medicine testing and nutritional strategies where appropriate. For more information, visit