"Non-COVID-19" Coronavirus Diseases Not to be Misdiagnosed as COVID-19.

Background: The COVID-19 global pandemic was caused by a novel coronavirus (SARS-CoV-2), which then became an endemic infection. COVID refers to the World Health Organization's coined acronym for coronavirus disease.

Case presentation: We have, herein, reported three cases of coronavirus diseases that could have been misdiagnosed as COVID-19. All of these families reported previous COVID-19 infection based on self-administered Rapid Antigen Testing (RAT) and completed a period of home isolation. In the current presentation, one child had an RSV-associated asthma attack, one had norovirus gastritis, and another had an infection with Campylobacter and E. coli. NL63, OC43, and 229E, respectively, were found by PCR in these patients.

Discussion: Seven human coronaviruses cause infectious diseases, including in children. Confusion and issues associated with coronavirus disease diagnosis by Polymerase Chain Reaction (PCR) testing and Rapid Antigen Test (RAT) may arise. Some RATs are Antigen Fluorescent Immunoassays (FIA) that target monoclonal antibodies for the detection of viral nucleocapsid protein. Others target the non-nucleocapsid proteins. False positivity is possible. False negativity is also possible if the specimen's antigen level is below the test's detection limit. RAT results usually remain positive for 6 to 7 days, but they may stay positive as long as 2 weeks. Stigmatization with the COVID-19 diagnosis may occur. The PCR test is a highly sensitive 'gold standard' for the detection of COVID-19, but it can also detect non-infectious individuals' fragmented non-infectious viral nucleic acids, and could be positive for a long period. An individual may be tested positive for a few weeks to months after the individual becomes non-infectious.

Conclusion: The cases presented here had coronavirus diseases other than COVID-19. Coronavirus diseases can be caused by coronavirus variants other than SARS-CoV-2. Co-infections with other pathogens are present in these diseases. PCR testing of non-COVID-19 diseases may help in the accurate diagnosis of these ailments and respiratory co-infections.