How Long COVID Keeps Us Sick

There is some evidence that vaccination may help reduce symptoms, but we need additional studies to confirm that finding

 
Other diseases with long-term symptoms can help us understand how COVID can affect us long after the virus itself is gone.

 
Understanding the effects of the COVID-19 pandemic on the population means knowing more than just the total number of infections and deaths. As with many diseases, after the acute infection has passed, a constellation of symptoms known as sequelae can still linger. And while the end of the pandemic is finally coming into view, we’re still in the early stages of comprehending post-acute sequelae of SARS-CoV-2 infection, also referred to as “PASC” or “long COVID.”

But COVID is far from the only infectious disease to result in long-term symptoms. Understanding this newly identified chronic illness and its associated symptoms could be guided by, and inform our knowledge of, other instances of post-infectious sequelae.

 
How can a virus still cause problems even after it’s gone?

There are myriad ways that infectious agents — viruses, bacteria, parasites, fungi and prions — can do long-term damage to the host, directly or indirectly. For instance, damage from the initial infection may cause a cascade of host responses that result in pathology even after the acute infection has resolved. This is sometimes referred to as a “hit-and-run” mechanism of disease, as the infectious agent is often gone by the time any post-infectious damage appears. Alternatively, microbes can infect us and then linger in our bodies for months or years as either a persistent active infection or a persistent nonreplicating (latent) infection. These infections can cause long-term damage via several different means, including inducing inflammation that leads to tissue destruction, or reactivation of a latent pathogen that begins reproducing again in times of stress.

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Πηγή: quantamagazine.org