New Delhi: As research on COVID-19 progress, a recent study found out that two other periods of illness appear to be temporarily associated with SARS-CoV-2 infection.
The study compiled by the Journal of the American Medical Association (JAMA) said that illness periods of a rare post-acute hyper-inflammatory illness, late inflammatory and virological sequelae not only define the temporal course of SARS-CoV-2 infection at the population level but also capture distinct phases of host-viral interaction.
A theoretical framework describing illness periods of SARS-CoV-2 infection (including clinical presentations and timing of onset), their pathophysiological underpinnings and associated key laboratory finding may contribute to a more inclusive, ordered understanding of the natural history of SARS-CoV-2 infection and enhance research efforts, the study said.
"Within the proposed framework, a patient may experience any combination of these illnesses or may have an asymptomatic infection without illness," it said.
Further describing the diseases, the study said that the onset of COVID-19 signs or symptoms is associated with viral replication and initial host immune response. "Asymptomatic SARS-CoV-2 infection may occur in 3 per cent to 67 per cent of infected patients and can be followed by other two illness periods, therefore, symptomatic infection is not a necessary precursor to later illness. The duration of acute infection is typically two days of weeks," the study said.
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The study said that post-acute hyper-inflammatory illness has been observed in both children and adults following acute SARS-CoV-2. "Distinct from early inflammation resulting from viral replication and cell death, hyper-inflammation can occur in organ system and can begin after host clearance of SARS-CoV-2," the study pointed out.
Patients may have prominent cardiovascular and gastrointestinal manifestations as well as dermatological and mucocutaneous manifestations similar to the hyperinflammatory condition of Kawasaki disease, it further said.
Referring to the late inflammatory and virological sequelae, it said that late inflammatory condition has been observed for several infectious diseases including lyme disease, syphilis, and ebola. "The etiologies of such late sequelae are not well characterised, but may reflect organ involvement during the acute infection period, the manifestation of a long term hyperinflammatory state, physical debilitation or psychological sequelae following a long or difficult disease course, or ongoing viral activity associated with a host of the viral reservoir, " the study said.
It is possible that the late sequelae of Covid19 represent multiple syndromes resulting from the distinct pathophysiological process along the spectrum of disease, it further said.
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