The current global pandemic is caused by the pathogen SARS-CoV-2, a member of the coronaviruses, which presents with a myriad of symptoms known as the disease COVID-19. One characteristic of the disease that has played a significant role in its catastrophic spread is that infected individuals can remain contagious long before they show symptoms and for some time after they feel better.
An unreviewed paper published on MedRxiv outlines the case of a male patient in China who exhibited the longest-recorded phase of viral shedding seen since the COVID-19 pandemic first began. Viral shedding is the stage of disease whereby a sick person is physically shedding the virus, for example in their mucus when coughing or sneezing, and is a factor that dictates the time healthcare officials advise we keep ourselves in quarantine when unwell. For COVID-19, the viral shedding phase is usually around 20 days with the longest previous recorded time being 37 days.
Prolonged viral shedding is typically associated with severe disease, putting patients at a higher risk of respiratory distress and death. Despite this, the gentleman in question suffered a non-severe case of COVID-19, contradicting what scientists previously believed about the typical behavior of SARS-CoV-2 in the human body.
This unusual pathogen behavior is what has led the researchers to believe they may have uncovered a subtype to the specific coronavirus sweeping the globe. Investigations into the clinical and epidemiological details of this specific patient revealed that this potential subtype of the coronavirus might be less deadly and harder to pass on, but render the patient contagious for longer and make it harder for them to kick the disease with conventional therapy. The patient was eventually able to overcome the illness after an infusion of plasma from a recovered patient.
The patient, who first presented in Wuhan on February 8th, could have had a mutated strain of SARS-CoV-2 that shows fewer symptoms but can spread for weeks. While this might be alright for healthy patients, it paints a worrying picture of “recovered” individuals returning to normal duties while they’re still contagious and coming into contact with those who have comorbidities. The extent of the reported patient’s symptoms was an intermittent fever for around seven days with no coughing or other associated symptoms.
The possibility of two main types of the SARS-CoV-2 pathogen existing is already being debated among scientists, who have theorized an L subtype and S subtype. The L type is believed to account for 70 percent of confirmed cases with a higher rate of spread compared to the S type.
In the paper, lead researcher on the study Dr Li Tan and colleagues said: "Currently, few studies focused on identifying the clinical features between these two subtypes, thus we cannot assure that Case 1-associated virus belongs to S type, mutated L type or a new subtype. Since the onset time of Case 1 revealed this mild subtype already exists at the early stage of outbreak when L type occupied dominant position, we cannot exclude an original new subtype that was not identified."