Discussion
So, in these two patients as we did not perform sequencing of the virus in each episode so we can’t prove that it’s a reinfection from another strain of the virus. But both patients had IgG antibodies present when they got second infection so ideally, they should not have got reinfected. Immune suppression due to chemotherapy may have reactivated the virus but there are no reports of the same in the literature. Same infection may have persisted but we have no proof of that as in between two episodes virus was negative by PCR. Ct values in first case at first diagnosis were high >30 so was it a false positive? At the time of second infection Ct values were low <20. But patient had IgG antibodies against SARSCOV2 present when he had second infection suggesting first infection was real infection. In second patient Ct values are low in both infection episodes and also, he had IgG antibody against SARSCOV2 at onset of second infection suggesting first infection was real and second infection is also real and possibly because of another strain. Most neutralizing antibodies target the spike protein (4). Several mutations in the spike protein receptor binding domain and N-terminal domain have been shown to confer reduced susceptibility to neutralizing antibodies (5). Both our patients had IgG antibodies against SARSCOV2 at the time of onset of second infection so only way new infection could have happened is if they got infection from a new strain of virus which could escape these antibodies.
Our two cases raise more questions then give answers. More data is needed to confirm this phenomenon of reinfection in Covid19.
Disclosure – All authors have nothing to declare. All authors have contributed to the manuscript.