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- Several countries reported recovered Covid-19 patients testing positive for a second time
- While they didn’t appear sicker, experts are not sure why this happens
- This study suggests that more attention should be given to discharged patients
While every recovery from from Covid-19 is a relief, we are still not familiar with all the after-effects of SARS-Cov-2, the virus that causes this disease.
A great concern for doctors is that some patients appear to test positive again after recovering from Covid-19, suggesting that they could still be carriers of the virus even after they’ve been discharged.
The study was conducted by a team from the Affiliated Hospital of Zunyi Medical University in China and was published in JAMA. The research team collected clinical data from patients who recovered from Covid-19 and were discharged from a hospital designated for Covid-19 in Guizhou Province, China.
Second time positive
The researchers examined data from 69 patients, with a median age of 33. From the base of the follow-up results, 11 of these 69 patients tested positive for Covid-19 after they were discharged. All of the patients were tested with the RT-PCR method, which is currently the most common test used to diagnose SARS-CoV-2.
The study results revealed that it took between nine and 17 days from discharge to testing positive again, which is longer than the original median period of 14 days that was mentioned in an earlier study, published on Healh24 in March 2020.
Why people test positive again
The phenomenon of people testing positive after recovery from Covid-19 has been investigated by several research teams to determine if these patients were actually reinfected.
It is accepted that one should produce SARS-CoV-2 antibodies after recovering from the virus. But according to some experts, these neutralising antibodies can be insufficient to provide immunity against Covid-19.
Different countries have reported patients testing negative, then positive again. But another study suggested that these patients were most likely not reinfected, but that the positive results could be due to shortcomings of the coronavirus tests.
According to Dr Oh Myoung-don, a doctor from Seoul National University Hospital, the current testing method (RT-PCR) can’t distinguish between active genetic material (the RNA) from a virus or the “dead” viral particles that remain in a person’s body even when they are healthy again.
It would require a completely different test to determine whether these patients are actually infectious again. According to the Korea Centers for Disease Control and Prevention, those patients in South Korea who retested positive had very little ability to spread the virus again.
No consensus
Even though the difference between active infectious viral particles and leftover “dead” viral material makes perfect sense, the existing data on the phenomenon is still limited.
And while those who tested positive again didn’t experience symptoms, this latest study suggests that doctors should be aware of the fact that patients can test positive more than once.
Image credit: Andrea on Pexel
