There's a lot of bullshit flying around regarding COVID-19 – from killing it by drinking hot tea to flushing if from the throat to the stomach with fluids – so here's my take:

Whilst one can and should take preventative measures – washing hands frequently, avoiding crowded places – once the virus is in your body there is only one thing that can fight it and that is your own body, in particular your own immune system. So take sensible steps to tonify the body and its immune system:

• Externally, with exercise – running and walking being the easiest. And if you can exercise mindfully – without headphones, paying attention to the body, breathing, heartbeat – then all the better. Catch the sun: there is nothing healthier than the winter sun so get as much of it as you can. The sea: the salt sea air is naturally invigorating and strengthening so make at least one weekly pilgrimage to the seashore. 
• Internally, with diet – add foods that are bitter, astringent or a little pungent: garlic, ginger, lemon, grapefruit (all citrus), apples, lettuce, radish, cabbage, spinach, chilli (a little), aduki beans, spring onions, bitter olive oil, seaweed, green tea. Avoid foods that mask bitter and sour, especially sweeteners, salt and seasonings, and dairy produce. Avoid tobacco, alcohol and anything stronger. Take a good (expensive) multi vitamin/mineral supplement. 
• Spiritually, with prayer, meditation or any sincere selfless activity. How can prayer help the immune system? The centre for the immune system is the thymus gland in the upper chest just behind the sternum. So prayer, which lifts this area upwards, – ostensibly to God but that doesn't really matter – focuses the mind and energy in the thymus. 

Above all, stay positive, be cheerful, help others and don't be fearful.