Why is it Some People who have COVID-19 are Sicker Than Others?

Caviarlieri | Published September 21, 2020

With the coronavirus spreading on for more than half of 2020 and still virulent in many countries, it seems that we have not fully scratched the surface yet of its full effect. The world’s esteemed doctors, scientists, biomedical engineers, pharmaceutical researchers and many other experts have already gathered so much data, testing and are still continuing to exhaust all efforts in the days to come just to put an end to this calamity which appears inexorable. We are already well-informed of the transmission, manifestations, tendencies, susceptible groups, and prognoses. But more peculiarities keep coming up in some findings and observations as the virus seems to work differently in many cases, revealing surprising changes and trends. This general uncertainty is one of the factors why it is so difficult to manage and treat unlike other infections that have definite presentations and more predictable prognoses.

Differing Symptoms

The most common signs and symptoms of COVID-19 are fever, chills, cough, shortness of breath or difficulty breathing, runny nose, fatigue and body aches. Some experience all of those symptoms combined and some just one or two. However, there are people who barely experience these COVID-19 symptoms but instead had unusual manifestations such as inability to taste and smell, feeling of suffocation, skin rashes and gastrointestinal symptoms. These unusual symptoms may not be immediately linked to coronavirus hence worsening the situation in terms of providing immediate care before their condition becomes complicated and making it difficult to prevent the local spread and to do contact tracing. In relation to this, one of the challenges with the coronavirus is that some people who contracted the disease display worse symptoms than others while some who are tested positive are asymptomatic and still healthy. And on the more extreme spectrum, some are tested negative despite similar exposures with those who contracted the virus. So, one of the most perplexing question in the mystery that is COVID-19 is– why do some people with COVID-19 get more sick than others?

Risk Factors and Reactions

The brutal truth is that experts have not yet been able to come up with a definite answer to these bedevilling questions. But there are some findings that may shed light on this matter and provide us some plausible explanation. One school of thought is that there is a high possibility that it is less to do with the virus and more to do with how our bodies respond differently to the infection. Since each human body is unique with its own genetic make-up, tolerance and immunity, this possibly explains why some people develop more severe reactions than others.. It is how the human body “hosts” the virus.

Initially experts have already identified groups of people who are at a higher risk of developing worse COVID-19 symptoms for obvious reasons– the elderly, those with underlying chronic medical conditions such as cancer and heart disease, obese, and smokers. But beyond that, there are new factors that have been discovered that explains why some people seem “protected” from becoming more sick or worse, dying from COVID-19.

Male – men have accounted for most infected cases in studies done in different countries. Genes’ part of the picture is that unlike men, women have two X Chromosomes which carries double copies of the gene TLR7 which is a key detector for viral action that helps boost immunity.

Type A blood – this blood type appears to have a higher risk of contracting the virus and develop serious complications. It is also linked to a 50% rise in the chances of a person needing supplemental oxygen or eventually a ventilator. Type O blood types appeared the least and seemed to have a partial protective effect. Another report on this is that persons with Type A blood have been linked to small blood clots that characterize severe COVID-19 cases.

Mode of transmission –There are varying points of view with the world’s medical authorities about how coronavirus is transmitted. And researchers suggest that the mode of transmission may play a part in the severity of the cases in a way that it spreads through tiny aerosol particles and not only through large respiratory droplets. These aerosol particles are able to penetrate deeper into the lungs and introduce the infection to the cellular level. So, the severity of the risk lies in how a person contracted the virus.

T Cells – an accidental discovery found that some people with less severe symptoms or those that are asymptomatic have developed some form of immunity through the T Cells. A particular study showed that people who have not encountered the coronavirus yet have already had T Cell reactivity against the virus. They suspect that this T Cell recognition of parts of the coronavirus may have come from exposure to one of the four known circulating coronavirus that is the cause of common cold affecting people every year.

COVID-19 in Children

Children are not as frail considering that COVID-19 symptoms in children are milder than in adults. This is a relief! It may manifest with the similar symptoms that of adults but very few end up in severe conditions and a fatal outcome is very rare. There are a few possible reasons brought up by pediatric immunologists as to why the coronavirus infection in children is mostly not life-threatening and manageable.

The airways of children have a common simultaneous presence of many viruses in the lungs and airways which could limit the coronavirus growth through interactions between viruses and competition.

There is a difference between the immune systems of adults and children, in their composition and how they respond functionally specifically in the expression levels of the ACE 2 receptor which is needed in the coronavirus binding and infection. This gene expression is lower in children and hence a lower chance of the virus to replicate in the body.

Children are less prone to developing Acute Respiratory Distress Syndrome (ARDS) than adults. ARDS is a complication of COVID-19 infections at the late phase.

All this information has been extremely helpful and vital to medical personnel and their approach in effectively managing COVID-19 cases. High risk cases can then be prioritized, vigilant attention is paid and those affected are provided with extra care to avoid more deaths. More discoveries are expected in the coming months to establish and identify more clearly how people can be susceptible to more severe reactions and this will help to solidify the battle against coronavirus through the most effective prevention management, treatment and vaccination.