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4th Edition of World Congress on Infectious Diseases

June 21-22, 2023 | Rome, Italy

June 21 -22, 2023 | Rome, Italy
Infection 2023

Jacek Z Kubiak

Speaker at World Congress on Infectious Diseases 2023 - Jacek Z Kubiak
Wojskowy Instytut Medyczny - PIB, Poland
Title : Higher proportion of SARS-CoV-2-positive children vs. adults detected as early as four mounts after the outbreak of 2020 COVID-19 pandemic in Warsaw, Poland


Early during 2020 COVID-19 pandemics the proportion of children vs. adults positive for SARS-CoV-2 in a RT-PCR test was shown to be lower in different countries. This suggested that children are more resistant to the novel infection than adults. Here we show that in Warsaw, Poland this proportion was also lower during the first three months of the COVID-19 pandemics (March-May 2020) and was as follows: 3.26% (15/459) positive cases among the symptomatic pediatric patients, 5.58% (99/1774) among the symptomatic adults, none in the asymptomatic children (0/445), and 0.83% (2/239) in the asymptomatic adults. However, already in June 2020, i.e. four months after the first case of COVID-19 was reported in this country, more symptomatic children were tested positive (28.44%) for SARS-CoV-2 than symptomatic adults (16.39%). This proportion returned to the advantage of adults (14.41%) vs. children (5.35%) in July 2020, and was inverted again in August and remained so during September 2020: children – 28.01% and 32.77% vs. adults – 21.33% and 27.15% respectively for August and September, respectively. These proportions, when calculated cumulatively for the four mounts period (June-September 2020) were as follows: children 26,17% vs. adults 20,24%. These data show important fluctuations in proportions of symptomatic SARS-CoV-2-positive children to adults at the beginning of the pandemics in Warsaw, Poland. It suggests that the initial lower proportion of contaminated/infected children vs. adults could be rather due to the restrictions introduced very soon after pandemics declaration in Poland, and possibly due to the hyper-protection of children by their parents at the very beginning of this period and not because of their higher resistance to the infection.

Audience take away:

  • We present here historical data concerning the beginning of the COVID-19 pandemics.
  • We show that the tendency of lower SARS-CoV-2 infection in children vs. adults observed in many countries was characteristic only to the very early stages of pandemics, and then fluctuated to invert the proportions.
  • These data show that the initial observations concerning unknown disease may rapidly change during the evolution of the pandemics.
  • It can provide a practical solution in case of future pandemics of a similar nature.


Dr. Kubiak studied Biology at the Warsaw University, Poland and graduated as MS in 1983. He then joined the research group of Prof. Andrzej K. Tarkowski at the Institute of Zoology, Dept. Biology, Warsaw University. He received his PhD degree in 1988 at the same institution. After three years postdoctoral fellowship supervised by Dr Bernard Maro at the Institute Jacques Monod, Paris, France he obtained the position at the CNRS in France. He is now in the CNRS, France and in WIM-PIB in Poland. He has published more than 140 research articles in SCI(E) journals.