What Factors Determine the Severity of COVID-19 in An individual?
My senior socialist friend Papa Jay El Capitano asked this question…“Not all the victims of Covid-19 were reckless in observing the safety protocols. Be sensitive in being judgemental.
Some (asymptomatic) were infected, recovered without any knowledge of their condition and, others infected and within the twinkle of an eye gave up the ghost.
Justice Boakye-appiah, we are told about immunities, underlying health conditions, etc but is there more to what accounts for the severity of the conditions?”
I do agree with you when you say not all Covid patients were careless. Absolutely true ! And that is why we do not have to be judgemental but rather be supportive and ensure that as we obey the rules, everyone else around us does same. Imagine your housemate catching the virus from whichever source and under whichever circumstance. You can’t possibly wear masks in your home at all times. You can’t completely avoid touching surfaces in your own home and try as hard as you may, touching your face in your sleep may be impossible. So it’s not just about you obeying the rules, you need to ensure that the people around you also do same . They may bring you trouble.
Now on to the substantive question of what the factors determining the severity of COVID-19 in an individual are:
1. Underlying medical conditions:
This is actually on two levels. There is the more commonly understood mechanism of a weak immune system as caused by whichever disease the person previously suffered. But there is also a very high risk of further damage to already diseased organs. Imagine a smoker with an already damaged lung catching COVID. There’ll be no long left by the time the virus is cleared. You need your heart to pump blood to all parts of your body. The requirement for blood supply increases when infected and so the workload on the heart also increases. Meaning your already diseased heart could get overworked and end up “breaking down” completely. You need your liver to produce proteins for the production of antibodies and other materials required to fight the infection. If your liver is already diseased from hepatitis, chronic alcoholism or any other condition for that matter, it could crush. Your kidneys are required to maintain normal internal conditions in your body despite the fluctuations ongoing. If the load increases and your kidneys get overworked, they may crush. Many people suffering hypertension, diabetes and other conditions are walking around with only partly functional kidneys. One of your kidneys may be completely damaged and yet not show any symptoms as the other one simply takes over the function of the faulty kidney. So it’s not uncommon for people with kidney disease to have no knowledge of this. That actually explains why you hear a lot of “There was nothing wrong with him oh. He just suddenly deteriorated and died”. You may actually die from accumulation of toxins which would otherwise have been excreted from your body by your kidneys and liver. So COVID may be the trigger but the cause of suffering and death may just be organ damage.
Right from onset, it was observed that older people suffered more severe disease than younger ones. Risk significantly increases after 60. Babies have a very low risk. Let me add that we are now seeing this age related risk increase even among people in their 40s. It is not just a factor of weak immunity as some say. Babies are considered to have weak immunity too. Their immune system takes time to develop but they aren’t suffering the same level of debilitation as the elderly. I do not intend to bore you with the very complex explanations and theories behind this but to only draw attention to the fact that this is not the time for grandparents to be picking the children up from school. As much as possible, they should be shielded. Children do not suffer severe disease but are very capable of spreading infections so shield the old people and keep the children away from them. Grannies may not live to tell their stories anymore.
3. Viral Load:
The general principle is that the number of viruses entering the body to cause disease does influence the severity of disease one suffers. And that is why health workers who by virtue of their work frequently get exposed to heavily infected patients are considered to be at a higher risk than normal. Your immune system is not likely to be overwhelmed by a low dose(inoculum) of viruses but a sudden exposure to huge viral copies may cause trouble. Again, this is why health workers working directly with Covid patients will need to take breaks after continuous periods of work. It is harmful to keep exposing yourself to high infection doses at close intervals: For an already understaffed healthcare system as ours, I do not even know how this can be achieved.
4. Viral Strain:
The issue of strains has become a big topic nowadays. Viruses are fast learners. They change their nature and features from time to time to help them survive and cause further disease. Let’s say a virus enters your body and your immune system kicks it in the head and thus manages to weaken it and prevent it from causing infection. The virus will learn to cover its head with a helmet next time. The helmet now helps it to survive and potentially adds on to its ability to cause more damage. The ability of a virus to do harm is termed VIRULENCE. For the virus, this is a survival adaptation mechanism but for humans, it is a dangerous phenomenon. The specific change the virus undergoes is what we call MUTATION and what it becomes is termed a new “STRAIN”. It maintains original features of the parent virus but adds on and/or changes some things to make it potentially more dangerous(Virulent). Brazil is currently battling a horrible strain which kills 3-5 times more than the original virus we first identified. Mutations are enhanced by repeated person to person transmission of viruses and I suppose you’ll quite easily understand why: It’s simply a factor of increased exposure and experience in dealing with mechanisms of the immune system. The more bodies viruses enter, the greater their ability to mutate so the most potent way of battling this whole phenomenon of new strains is fundamentally blocking transmission by obeying COVID rules.
My bigger fear is that if we keep misbehaving and allow the virus to keep mutating, we may have a strain which will not only be able to dodge our immune system but will also be able to dodge vaccines. That may be checkmate for us!
5. 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 your 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 “corona virus”. There are many types of corona viruses. 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 corona virus 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.
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 your 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.
7. 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 suregeries, 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.
Your question is a very difficult one. It could easily pass as a medical school viva question lol
But off the top of my head, these are the factors I’m able to recall. There may be more. I hope this helps.