The reinfection or reactivation of Sars-Cov2 which causes Covid-19, as reported in some parts of the world, is actually a result of prolonged shedding of the virus complemented with occasional false positives or negatives and lab errors, argues an editorial published on Qatar Medical Journal.
The article, ‘Cases and etiologies of suspected Covid-19 reactivation', featured on QScience.com and written by Abdullah Ghali, Juan Simon Rico-Mesa, Mouhamed Nashawi and Jose Cadena from the Department of Medicine, Division of Internal Medicine, University of Texas Health San Antonio, San Antonio states, “the study outlines a perspective on Covid-19 reactivation with considerations of implored commentary on behalf of the medical community regarding open discourse about this subject.”
According to the researchers, “The article was written with the perspective of informing in addition to engage discussions that distill salient, evidence-based characterisation of Covid-19. We hope to recruit fellow academics in medicine who see trends in their own respective communities about people who retest, and to explore their clinical outcomes.”
The article notes that preliminary findings about viral dynamics have been alarming in countries such as South Korea and China, which experienced some of the earliest interactions with Covid-19. These countries have implemented sweeping societal changes based on limited contact procedures to mitigate viral spread. However, reinfections, with rate as high as 14%, have been reported in these countries.
“The period where patients have negative to positive test results ranged from 4 to 17 days, suggesting that recovered patients may need further isolation and viral detection. Considering the effects of loosening contact precautions or instituting more strict guidelines, it is necessary to consider the possibility that several patients considered to experience Covid-19 reactivation are likely to have false-positive test results,” highlights the article.
As per the study, the prolonged shedding of Sars-Cov2 observed in several recorded patients may explain why certain patients have positive test results during retest.
“Although some patients with a previous history of Sars-Cov2 infection may present with similar earlier symptoms, they may be incorrectly diagnosed with Covid-19 reactivation. These late symptoms can be a manifestation of a cytokine storm (a physiological reaction in humans) rather than a viral reactivation. Such findings have prompted the World Health Organisation to begin systematic investigations on the nature of long-term viral dynamics, including the half-life of Sars-Cov2,” explains the study.
The study also maintains that the presence of Covid-19 reactivation or reinfection in patients who initially had RT-PCR negative test results and subsequently positive test results remains unclear. With viral load use and insufficient viral culture, available information used to formulate a conclusion is considered insufficient.
The researchers of the study feel that although Sars-Cov-2 displays active replication concurrently with upper respiratory tract symptoms, viral shedding is prolonged, outlasting the resolution of symptoms, where viral load did not rapidly decline as would have been expected. It also points out that shedding reaches its maximum values in the first week of symptom onset, peaking on day four. The period where a test result changes from negative to positive ranged from 4 to 17 days, suggesting that recovered patients may need further isolation and viral detection.
“Furthermore, based on the existing evidence, false-negative test results may also be observed with RT-PCR while displaying positive findings on CT scan. Although the evidence regarding the subsequent Covid-19 reactivation seems unlikely, the potential risks are significantly high to cast this differential aside. Although the potential consequences of viral reactivation may warrant further scientific studies, countries with first reports of perceived recurrence of Covid-19 positive test results, namely, South Korea and China, have yet to support these data with valid scientific evidence,” concludes the study.