The best way to protect yourself from communicable respiratory diseases, like the flu or the novel coronavirus is to avoid coming in contact with the virus in the first place.
This means that your first line of defense is to try to avoid sick individuals where possible and to practice proper sanitation and hygiene practices. But beyond that, our immune systems can and do ward off infectious pathogens every day. This includes various strains of the flu virus, including the novel coronavirus. And if you were to contract the coronavirus also called COVID-19, the response of your immune system is your primary means of combating and survive the disease.
It is important to understand that individuals with comorbidities, which means the simultaneous presence of two chronic diseases or conditions, are the most likely to suffer from serious cases of influenza - including the novel coronavirus. This is because comorbidities, which are existing or concurrent medical conditions that already tax and or otherwise compromise the immune system, hinder the immune systems' ability to maximally fight infectious diseases such as COVID-19.
Simply put, the healthier you are and the stronger your immune system is, the better equipped your body is to fight back against communicable disease initially and potentially prevent infection and once infected, fight back against any disease, including coronavirus.
So how do you ensure you are doing what you can to keep your immune system running optimally?
Let's look at what science-backed actions can be taken to ensure your immune system is as strong as possible.
Here is the MyID top 6 list
1. Get adequate sleep
A growing body of research suggests that adequate sleep is essential to maintain optimal health, and this applies to the immune system as well. While one night of bad sleep is not a cause of concern, chronic poor or short sleep can lead to compromised immune function. Getting at least 7 hours of sleep is key to keeping your immune functioning optimally. 
2. Get regular exercise
Research linking moderate levels of exercise to enhanced immune function is extremely strong. This is no surprise, as exercise has been shown to activate myriad cellular pathways that reduce inflammation and activate a process called autophagy which is a form of cellular housecleaning in which your cells will destroy faulty strictures to include foreign pathogens clearance. 
3. Increase your Fruit and Vegetable intake
A diet rich in fruits and vegetables may reduce inflammation which is associated with increased risk across a wide variety of diseases. In addition to reducing inflammation, Various compounds contained within fruits and vegetables such as antioxidants and polyphenols may act to enhance the immune system.
4. Eat Meat or supplement with carnosine
Carnosine is a potent antioxidant that has been shown to help reduce inflammation and modulate (improve) immune function.  What is incredibly interesting about carnosine is that it has been shown in studies to inhibit infection of, and directly improve outcomes in subjects infected with influenza. Carnosine has even been suggested as a possible therapeutic prevention treatment in the case of global influenza pandemics, which may include coronavirus strains. 
5. Ensure your vitamin D levels are not low
Vitamin D levels are directly correlated to immune function. The higher your vitamin d levels are, the stronger your immune system is.  Beyond generally enhancing immune function, vitamin d has been shown to prevent acute respiratory tract infections such as flu strains and that may include coronavirus strains such as COVID-19.
The body naturally synthesizes vitamin D via sunlight on our skin, which means that vitamin D status is lowest in winter months when days are short, or for those of us who spend little time outdoors. Up to 50% of the earth's population is chronically low in vitamin D. 
If you suspect you may be low in vitamin D, you can spend more time outdoors in sunlight, supplement with vitamin D, or eat foods high in vitamin D such as eggs, seafood, mushrooms, or fortified foods such as milk or cereals.
6.) Drink tea or eat dark chocolate
Polyphenols found in plant foods have an immune-enhancing effect. Chief among these polyphenols are catechins such as EGCG and epicatechin. Drinking green tea or eating low sugar dark chocolate may provide an effective dose of catechins to help boost immune function and assist in both the treatment and prevention of infections, specifically influenza strains such as coronaviruses, including COVID-19. [12}
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