Why so many COVID positive patients experience no symptoms?

Why so many COVID positive patients experience no symptoms?

According to a study done by the University of Arizona, USA, SARS-COV-2, the deadly virus which is responsible for causing the COVID infection in humans may actually be impacting certain cells in the body, relieving pain and making patients experience next to none symptoms.

The newest research might hold a clue as to why, asymptomatic patients, more than half of the infection cases experience no symptom or signs but continue to spread the infection in huge numbers.

Pain suppression to be the reason?

According to Dr Rajesh Khanna, a professor in the College of Medicine—Tucson’s Department of Pharmacology, the reason some patients experience zero symptoms of COVID-19 is that the virus may be causing pain suppression, especially in the early stages. Since such patients may experience no change in their vitals, they may go about their usual routine, thereby transmitting the infection onto others, knowingly or unknowingly. It should also be noted that the earliest days of infection, are considered to be the most contagious.

The study, which will soon be published in the journal, PAIN, International Association for the Study of Pain mentions:

“It made a lot of sense to me that perhaps the reason for the unrelenting spread of COVID-19 is that in the early stages, you’re walking around all fine as if nothing is wrong because your pain has been suppressed. You have the virus, but you don’t feel bad because your pain is gone. If we can prove that this pain relief is what is causing COVID-19 to spread further, that’s of enormous value.”

Figures by the Centres of Disease Control and Prevention (CDC, USA) also suggests that a big percentage of transmission risk (upto 40%) occurs in the earliest of days before symptoms set in (i.e. asymptomatic phase).

The findings can also provide some clue to the fact as to why do two persons, diagnosed with the same infection experience such different symptoms.

But why does the body experience no pain?

Although there are more ongoing studies going on, one reason behind being asymptomatic, or having ‘painless COVID’ could be the way SARS-COV-2’s spike protein might be interacting with the body’s pain receptor cells, thereby silencing it. Hence, one way of tackling this is to neutralize the spike protein of the virus.

The way SARS-COV-2 attacks our body is by attaching itself to the ACE-2 receptors. However, recently, scientists were able to make the discovery that there’s yet another way the virus enters- by using the help of a receptor cell, neuropilin-1. Interestingly, the proteins and pathways associated with this specific receptor cell, neuropilin-1 are involved in pain processing and relieving. When the COVID causing virus does attach to this specific cell, it limits the function of the vascular endothelial growth factor-A (VEGF-A), which is involved in neural function and pain receptivity, ergo, making people experience zero symptoms.