Introduction: The COVID-19 pandemic is now rapidly growing, with over one million and 300 thousands infected persons and over 75,000 deaths all over the world.

Case experience: We were asked to see a male patient in late December 2019 by a colleague specialized in chest medicine. The patient was medical person, with history of direct contact to people from many different countries. He was middle aged, diabetic and presented to chest doctors as a case of severe pneumonia and resistant fever. He received many combinations of antibiotics and antiviral therapies, but with no improvement, and finally he needed to be ventilated. Knowing some idea about the pathogenesis of COVID-19 disease raised this question in our minds: Could this patient be an undiagnosed COVID-19 case?

Conclusion: COVID-19 may be present inside human beings long before its actual discovery in late 2019, and many of the undiagnosed severe respiratory symptoms may had COVID-19. The actual prevalence of COVID-19 may be much wider than the recorded numbers all over the world, and this means that the mortality rate of this virus is much lower than recorded because many cases may pass asymptomatic and not included in the total number of COVID-19 cases. We may have reached already the herd immunity target, and COVID-19 may have reached its peak spread, especially in countries with earlier exposure to it.