Challenges of diagnosis of hidden fungal infections as sequelae in post-coronavirus disease patients

More than 700 million people worldwide have been confirmed to have coronavirus disease 2019 (COVID-19), putting them at risk of developing sequelae that are prone to invasive fungal infections (IFIs), such as candidiasis, aspergillosis, and cryptococcosis. These fungi are generally not virulent, but in patients with a history of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, they can cause opportunistic infections due to immune dysregulation and abnormalities in lung tissue structure caused by the effects of the SARS-CoV-2 virus, history of using immunosuppressive drugs or invasive medical devices during treatment, and so on. The increased susceptibility to IFIs in individuals post-COVID-19 requires rapid and efficient diagnostic methods. Currently, commercially available antigen-based serological tests have good sensitivity and specificity, and some have been approved for use by the Food and Drug Administration. Thus, antigen-based screening tests are essential in developing regions with limited resources.