Patients recovered from COVID-19 and discharged from hospital after fulfilling the criteria of discharging (WHO), so any chance of COVID-19 relapse in a recovered patient is there or not?
Yes many cases are reported in different territories of the world. SARS-CoV2 is RNA virus so it is more prone to mutation this lead to multiples serotypes of virus as more than three serotypes are identified so far. If a person infect once with one serotype there is chance for this person to get infect with other serotype. Multiple seroptypes not only causes re-occurrence of infection but also it interfere with disease clinical consequences, laboratory diagnosis and Vaccine preparation.
Presumably if people had been treated in hospital, the infection had been severe.
I had heard that in mild cases of COVID-19 result in fewer antibodies and further infection is more likely. I tried to find information to support this supposition:
From Vox:
What immunity to Covid-19 might actually mean
https://www.vox.com/science-and-health/2020/4/23/21219028/covid-19-immunity-testing-reinfection-antibodies-explained
From South China Morning Post:
Coronavirus: low antibody levels raise questions about reinfection risk
https://www.scmp.com/news/china/science/article/3078840/coronavirus-low-antibody-levels-raise-questions-about
From NBC News:
Antibody tests can't yet say who's immune to COVID-19, but they can show who's at risk
https://www.nbcnews.com/health/health-news/antibody-tests-can-t-yet-say-who-s-immune-covid-n1193321
There is chance for relapse after recovery from covid-19 therefore preventive measures should be continued to avoid recurrence.
No reinfection or recurrence clearly documented in a recovered COVID-19 if we judge by symptoms, lab and radiological evaluation and contagiousness, not by CT-PCR results
It is not yet established that patients who are declared recovered from COVID-19 on the basis of two NEGATIVE RT-PCR tests for SARS-CoV-19 had actually recovered due to laboratory error of testing kits or the the positivity indicates a carrier state, as none of these reports indicated any worsening of clinical condition of the patient based on symptoms, CT-scan or other parameters (1). We have seen many patients with COVID-19 who despite making a clinical recovery are often having positive reports based on the RT-PCR results up to 35 days after initial diagnosis (2). There has been talk of viral RNA belong to dead virus (viral litter, debris) as the explanation for positive RNA-based PCR tests, as this test does not establish the presence of live virus.
Important point is that there is a disconnect between positive tests and the clinical condition of the such COVID-19 patients. If you follow up such patients, none of the patients had adverse outcome.
1.Preprint Clinical characteristics of the recovered COVID-19 patients ...
2. https://www.researchgate.net/post/What_are_the_interpretations_and_implications_of_having_negative_followed_by_positive_RT-PCR_tests_in_COVID-19_patients
Please go through the attached link..
Article Recurrence of positive SARS-CoV-2 RNA in COVID-19: A case report
Yes, there is. This discussion link, with a similar question, may be useful:
https://www.researchgate.net/post/Is_one_immuned_to_COVID-19_after_getting_infected_once