The iceberg of COVID-19: are there asymptomatic cases below the surface?
The number of COVID-19 diagnosed patients may represent just the tip of the iceberg. To date, epidemiological studies that provide an accurate idea of asymptomatic cases are scarce.4,5,93 Most of the identified asymptomatic cases are diagnosed by random screening of healthcare workers, and individuals who had been in close contact with COVID-19 cases.49 In addition, there is a high number of asymptomatic individuals who have experienced COVID-19-like symptoms in their clinical histories without any diagnostic tests and hospital admission. Due to the nature of this disease, it is difficult to identify asymptomatic virus carriers and it is one of the challenges faced in the containment of the pandemic.5 The real percentage of asymptomatic individuals and how long they carry the virus is unknown. Large screening studies for virus-specific IgM, IgG and IgA will be a decisive factor in controlling the pandemic, as it is the main indicator of the development of population immunity.