From the observations coming from the previous studies, it has been seen that the samples from patients who recovered from an initial COVID-19 illness and later developed new symptoms and retested positive by RT-PCR (Reverse transcription polymerase chain reaction) were not capable of detecting the virus. Some previous studies have shown that the SARS-Cov-2 virus can replicate inside the body and is released into the environment from the people having low immune system at that point, making these individuals contagious. However, when infected with SARS-Cov-2 virus, the chances of person recovered from the infection, capable of spreading the virus through upper respiratory tract after the beginning of the initial symptoms of the disease, are very low.

Currently, there is only one published study which provides the elements of the persistence of SARS-CoV-2 in individuals who have low ability to fight against infections. The data from other studies of Tata Memorial Hospital show that the patients on active chemotherapy might be at increased risk of worsening their basic cancer treatment due to the positive nasopharyngeal (NP) swab which delays the administration of chemotherapy. In some previous studies, positive nasopharyngeal swabs were shown to detect virus but failed to detect replication and growth capacity of the virus.