Objectives Possibility of reinfection with SARS-CoV-2 changes our view
on herd immunity and vaccination, and can impact worldwide quarantine
policies. We performed RT-PCR follow-up studies on recovered patients to
assess possible development of reinfections and re-positivity. Method
During a 6-month period, 202 PCR-confirmed recovering COVID-19 patients
entered this study. Follow-up RT-PCR tests and symptoms assessment were
performed one month after the initial Positive results. patients who
tested negative were tested again one and three months later. The Serum
IgG and IgM levels were measured in the last follow-up session. Results
In the first two follow-up sessions, 82 patients continued their
participation, of which four patients tasted positive. In the second
follow-up 44 patients participated, three of whom tested positive. None
of the patients who tested positive in the first and second follow-up
session were symptomatic. In the last session, 32 patients were tested
and four patients were positive, three of them were mildly symptomatic
and all of them were positive for IgG. Conclusion A positive RT-PCR in a
recovering patient may represent reinfection. While we did not have the
resources to prove reinfection by genetic sequencing of the infective
viruses, we believe presence of mild symptoms in the three patients who
tested positive over 100 days after becoming asymptomatic, can be
diagnosed as reinfection. The IgG may have abated the symptoms of the
reinfection, without providing complete protection.