Many people are recovering from COVID-19, an unanswered question is the extent to which the virus can “hideout” in seemingly recovered individuals.
If it does, could this explain a number of the lingering symptoms of COVID-19 or pose a risk for transmission of infection to others even after recovery?
What is the chronic or persistent viral infection?
A chronic or persistent infection continues for months or maybe years, during which era virus is being continually produced, albeit in many cases at low levels.
There are a couple of places within the body that are less accessible to the system and where it’s difficult to eradicate all viral infections.
These include the central system nervous, the testes, and therefore the eye.
An immune-privileged site not only is difficult for the system to enter, it also limits proteins that increase inflammation.
The rationale is that while inflammation helps kill a pathogen, it also can damage an organ like the attention, brain, or testes.
A latent infection versus a persistent virus infection
A latent virus infection occurs when the virus is present within an infected cell but dormant and not multiplying.
During a latent virus, the whole viral genome is present, and therefore the infectious virus is often produced if latency ends and the infections become active.
The latent virus may integrate into the human genome, as does HIV, for instance – or exist within the nucleus as a self-replicating piece of DNA called an episome.
A latent virus can reactivate and produce infectious viruses, and this will occur months to decades after the initial infection.
Perhaps the simplest example of this is often chickenpox, which although seemingly eradicated by the system can reactivate and cause herpes zoster decades later.
Fortunately, chickenpox and zoster are now prevented by vaccination.
To be infected with an epidemic capable of manufacturing a latent infection is to be infected for the remainder of your life.
How does an epidemic become a latent infection?
Herpes viruses are far and away from the foremost common viral infections that establish latency.
This is an outsized family of viruses whose genetic material, or genome, is encoded by DNA (and not RNA like the new coronavirus).
Herpesviruses include not only herpes simplex viruses 1 and a couple of – which cause oral and herpes genitals – but also chickenpox.
Other herpes viruses, like Epstein Barr virus, the explanation for mononucleosis, and cytomegalovirus, which may be a particular problem in immunodeficient individuals, also can emerge after latency.
Viruses that establish latency in humans are difficult or impossible for the system to eradicate.
That’s because during latency there is often little or no viral protein production within the infected cell, making the infection invisible to the system.
Fortunately, coronaviruses don’t establish a latent infection.
Could you catch SARS-CoV-2 from a male sexual partner who has recovered from COVID-19?
In one small study, the new coronavirus has been detected in semen during a quarter of patients during active infection and during a bit but 10 percent of patients who apparently recovered.
During this study, viral RNA was what was detected, and it’s not yet known if this RNA was from the still infectious or dead virus within the semen; and if alive whether the virus is often sexually transmitted.
Numerous important questions remain unanswered.
Where else could the new coronavirus persist after recovery from COVID-19?
Other sites where coronavirus has been detected include the placenta, intestines, blood, and in fact the tract.
In women who catch COVID-19 while pregnant, the placenta develops defects within the mother’s blood vessels supplying the placenta.
However, the importance of this on fetal health is yet to be determined.
The new coronavirus also can infect the fetus via the placenta. Finally, the new coronavirus is additionally present within the blood and therefore the cavity and palate for up to a month or more after infection.
The mounting evidence suggests that SARS-CoV-2 can infect immune-privileged sites and, from there, leading to chronic persistent, but not latent, infections.
It’s too early to understand the extent to which these persistent infections affect the health of a private just like the pregnant mother, for instance, nor the extent to which they contribute to the spread of COVID-19.