- Hyper-Active Immune Responses:
We have drummed home the fact that one needs a strong immune system to be able to ward off the disease, but an overactive immune response could paradoxically also kill. One mechanism by which virus destroys the lungs is by inducing what we call a cytokine storm. Cytokines are chemicals produced by cells of the immune system to fight off viruses and bacteria. Their toxic effects on these viruses can also be exerted on your own organs and so must at all times be regulated by the body to ensure balance. As one of my medical school lecturers often said, “That same insecticide you use to clear the mosquito can as well clear your own body cells. It’s just a matter of quantities and sometimes mechanisms”. Cytokines are secreted by cells of the immune system in response to memory. So, if you have been repeatedly exposed to viruses similar in structure and appearance to the COVID-19 virus, your body is likely to respond more aggressively with the secretion of more cytokines when you catch the infection. Think of how vaccines work and this will be clearer.
Note that I avoid using the loose term “coronavirus”. There are many types of coronaviruses. What we are dealing with at the moment is only one kind. SARS (Severe Acute Respiratory Syndrome), MERS (Middle East Respiratory Syndrome) and a number of other infections we have known for decades are caused by members of the coronavirus family. Corona just means crown and describes the shape of the viruses belonging to this family. They all share a common stem structure but go on to vary when examined in detail. So, if you have been exposed to any of these viruses before, infection with the COVID-19 virus will not be your immune system’s first encounter. It’ll immediately “remember” that common stem and respond aggressively with its many mechanisms including the secretion of cytokines. Double trouble! The virus is causing excess cytokine secretion to destroy your lungs and your body is also responding to the presence of this same virus by secreting excessively high amounts of cytokines. Cytokines, which were originally meant to protect you, now harm you by destroying your own organs. This is one of the theories believed to underlie the discordance between age and immune strength that I mentioned earlier. Older people are potentially more likely have been exposed to members of this viral family in the past and so the severity of the disease for them is more likely to be due to this exaggerated immune response rather than a “weak” immune system. If the risk faced by the oldies were just a matter of weak immunity, babies would have suffered same. They have reduced immunity too. But it isn’t so.
This also explains why previously infected people may suffer a fever or some symptom of a sort when they take COVID vaccines. It also explains why people who were very okay after their first dose of the COVID vaccines may develop some fever or malaise after taking the second dose. It’s “memory”. Your immune system will be responding to something it has seen before. In the case of the vaccines, some tablets of paracetamol will fix the problem without sweat. It is an expected effect, so don’t be worried if it happens.
- Genetics:
Genetic features affect everything. Some people by virtue of their genetic makeup are naturally prone to severe disease. It may just be that they have many of docking sites the virus prefers. The virus enters happily and goes on to cause havoc with little resistance. You may have heard people say some months back that blacks were immune to the virus because we had reduced binding/docking sites (ACE receptors) for its action. Even though this claim has been found to be untrue, that would have been an example of how genetics could either protect you or put you at risk of more severe disease. It isn’t a new phenomenon. We have for years known the role of genetics in these things. Even for HIV, you may be surprised to learn that some people by their genetic makeup CANNOT be infected. Others are likely to more readily catch the virus. There have been some findings on genetic predisposing factors and there is still a lot of work going on. Since it is impossible to determine these things by simply looking into people’s faces, we may not know our risk level and so should be keen to obey the rules.
Clotting:
One major mechanism by which COVID causes death and severe disease is by causing blood to clot in the body. The clots are then lodged in the lung vessels to occlude and obstruct blood flow to and from your lungs. That kills faster than many other things. Even without COVID, pulmonary embolism (clots in your lung vessels) is a feared medical condition, so imagine being at risk of it and catching COVID. Dangerous! Obese people, immobile individuals, pregnant women, women on oral contraceptives, people with cancers, people recovering from surgeries, individuals lacking certain natural proteins, etc are at increased risk of developing clots, so their risk of severe COVID multiplies. If you belong to any of these categories or have ever had a blood clot in your limbs or lungs, please be extra careful.
BY Dr. Justice Boakye Appiah