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.