COVID-19 keeps on posing new challenges and creating controversies for health care providers. One of the controversy is reinfection; is it a reality or just a myth . Reinfection also raises many questions about the way forward in tackling this scourge—and will go a long way in attempting to make the right public health policy. Cancers are one of the vulnerable groups where COVID-19 can be severe and lead to fatality . All our three patients are high-risk immunosuppressed patients suffering from established hematologic malignancy on chemotherapy, who were documented to have achieved RT-PCR negativity after a bout of infection. The three patients subsequently became positive for the virus after 84 days, 91 days, and 60 days of returning a negative RTPCR report, respectively. In two of these three patients, the second infection was severe as per risk stratification , which raises a possibility of “antibody-dependent enhancement” classically seen in severe dengue infection . Or is the absence of protective antibodies in our patients, consequent to their immunosuppressed state, the reason behind acquiring a second bout of the infection? It also begs the question of whether the antibodies protect the individual from infection, or disease, or neither and whether quantifying antibody levels in recovered patients is a good idea to evolve answers to these questions in the future.
Even as dynamic PCR results have raised a possibility of oscillating positive/negative reports in COVID-19 patients , all three of our patients were symptomatic, more so the second time around, which raise a serious concern that reinfection is no longer a myth in COVID-19 especially in immunosuppressed population. Another possibility to be considered is reactivation of dormant virus which is commonly seen in immunosuppressed with viruses like cytomegalovirus (CMV), herpes group, and Ebstein Barr virus (EBV). This issue of viral reactivation or reinfection with a different strain can be resolved by sequencing of viral genome during the suspected reactivation, which could not be done for our patients.
Question arises, whether these patients, and others who have to undergo chemotherapy and live with its possible consequence of immunosuppression, are better off delaying the same during the pandemic to avoid risk of reinfection? Or, is an active surveillance of all patients on chemotherapy, the way forward? Most patients of aggressive hematologic malignancies will relapse and develop a refractory disease if there are breaks in chemotherapy protocol; hence, it is recommended to continue with chemotherapy in these patients. Patients with indolent hematologic malignancies, and in patients with known risk factors of severe COVID-19 infection like advanced age, multiple co-morbidities can be started on less intense chemotherapy protocols. In addition, all patients on chemotherapy should be on active surveillance by a combination of nasopharyngeal or oropharyngeal RT-PCR testing for the presence of SARS-CoV-2 infection along with surveillance antibody screen at the start of each chemotherapy cycle. To conclude, there is an urgent need to systematically study all reported cases of reinfection, particularly in immunosuppressed patients.