Introduction: In Hungary, SARS-CoV-2 was first detected in the swab samples of two
Iranian patients on March 4, 2020. After finding the first positive cases, the question
arose whether the virus had entered Hungary and caused infections before this date.
Before March 4, 2020, except for the two above-mentioned samples, none of the 224
swab samples received specifically for SARS-CoV-2 tested positive. Aim: The National
Reference Laboratory for Respiratory Viruses of the National Public Health Center
aimed to carry out a retrospective study of the swab and other samples taken for testing
respiratory virus infections between January 1, and April 19, 2020 sent by sentinel
physicians within the influenza surveillance for diagnostic purposes. Method: For
the study, we used swab samples taken weekly by sentinel physicians of the influenza
surveillance service, and other samples received for diagnostic purposes. Tests were
performed using real-time PCR. Results: All the 465 swab samples sent by sentinel
physicians were found to be SARS-CoV-2 negative. Also, of the 551 samples collected
for diagnostic reasons of other respiratory viruses, no SARS-CoV-2 positive was found
among those taken before March 4. Conclusion: Based on our data, it is very likely
that prior to the first cases diagnosed on March 4, 2020, SARS-CoV-2 did not cause
clinically symptomatic infections in Hungary.
