Seroprevalence of Helicobacter pylori infections in children and adults in Poland in the years 2020-2023.

Introduction: Helicobacter pylori is a common cause of gastrointestinal infections in people around the world. Various microbiological methods are used in the laboratory diagnosis of infections, including determining the presence of specific antibodies in the serum. Serological tests can also be used in epidemiological studies aimed at determining the incidence of H. pylori infections. Objective: The aim of the study was to obtain insight into the incidence of antibodies to H. pylori in subjects of different ages living in Poland in the years 2020-2023. Material and methods: The research used serum samples obtained between January 2020 and September 2023 from 600 subjects living in Poland. The Anti-Helicobacter pylori ELISA IgG enzyme immunoassay from Euroimmun was used to test the level of IgG antibodies to H. pylori antigens. Additionally, selected serum samples were tested for the presence of antibodies to the most important protein virulence factors of H. pylori by Western Blot. Results: IgG antibodies to H. pylori, at a diagnostically significant level, were detected in 28.3% of the examined persons. Antibodies to H. pylori were least frequently detected in children under 10 years of age (12.1%) and teenagers (13.2%). In adults aged 20 to 50, these antibodies were more common (23.9% to 29.5%). Statistically, H. pylori antibodies were most often detected in subjects over 50 years of age (52.3%). There were no statistically significant differences in the frequency of antibodies to H. pylori depending on the gender of the examined persons. In most serum samples tested by Western Blot, the presence of antibodies to the CagA protein was detected (66.7%). Conclusions: The conducted research and analysis of literature data showed a similar percentage of serum samples with a diagnostically significant level of antibodies to H. pylori in people living in Poland as in people living in other European countries. The epidemiology of infections is also very similar, characterized by low morbidity in children and adolescents and an increase in the incidence of infections with the age of the examined persons. Importantly, compared to research conducted in our country several years ago, the percentage of positive results is much lower, which may be due to the improvement of social and living conditions and hygiene habits.

The level of protective post-vaccination antibodies in NIPH-NIH employees after administration of Pfizer vaccine against COVID-19.

INTRODUCTION: The new SARS-CoV-2 coronavirus, first recognized in China in 2019, within a few months caused a global pandemic of a disease called COVID-19. The high incidence and mortality of COVID-19 was the reason for the beginning of intensive work on the development of an effective vaccine. In Poland, mass vaccinations against this disease began at the end of December 2020. OBJECTIVES: The aim of the presented study was to determine the effectiveness of stimulating the production of specific antibodies for SARS-CoV-2 by the Pfizer vaccine. MATERIAL AND METHODS: The presence of IgA and IgG antibodies to the spike (S protein) of SARSCoV-2 was tested by the ELISA/Euroimmun in serum samples obtained from 140 the employees of NIPH-NIH (137 were vaccinated). In addition, the presence of IgG antibodies to S protein, nucleoprotein, and mixture of both in selected serum samples was tested by the newly developed in NIPH-NIH in-house ELISA assay. RESULTS: IgA and IgG antibodies to the S protein of the SARS-CoV-2 were detected by ELISA/Euroimmun, respectively in 136 and in all 137 vaccinated persons. There were no statistically significant differences in the level of antibodies depending on the sex and age of the vaccinated persons. Slightly higher levels of antibodies have been demonstrated in vaccinated subjects with documented preexisting SARS-CoV-2 immunity compared to subjects without COVID-19 history. The presence of IgA and IgG antibodies was found in respectively, 18 (45.0%) and all 40 (100.0%) tested vaccinated persons by the in-house ELISA with mixture antigen. The study showed that ELISA assay with N protein as an antigen may enable the distinction between antibodies acquired after infection and after vaccination. CONCLUSIONS: The results obtained in the presented study clearly demonstrate the high effectiveness of the Pfizer vaccine in stimulation of the human immune system to produce antibodies specific for the S protein of the SARS-CoV-2. It is necessary to continue testing vaccine antibody levels at various times after vaccination to determine the potential duration of humoral immunity.