Influenza Hemagglutinin Antibody Levels in the Elderly: Impact of Sex, Age, and Influenza/COVID-19 Vaccination Status During the 2021/2022 Epidemic Season in Warsaw, Poland.

BACKGROUND The purpose of the study was to determine the level of antihemagglutinin antibodies in the serum of patients in the geriatric population in Doctor's Surgery NZOZ Nucleus Warsaw, Poland, during the epidemic season 2021/2022 using the hemagglutination inhibition assay (HAI), according to anti-influenza and anti-COVID-19 vaccination, age, and sex. MATERIAL AND METHODS Serum samples taken from 256 patients aged 65 to 99 years were examined for anti-hemagglutinin antibodies and protective levels of antibodies against antigens: A/Victoria/2570/2019 (H1N1)pdm09, A/Cambodia/e0826360/2020(H3N2), B/Washington/02/2019 (B/Victoria lineage), and B/Phuket/3073/2013 (B/Yamagata lineage) of the quadrivalent influenza vaccine for epidemic season 2021/2022. RESULTS The highest protective level, ie, the percentage of people with antibody titers ≥40 was 87.

Occurrence of Circulating Antibodies against the Hemagglutinins of Influenza Viruses in the 2022/2023 Epidemic Season in Poland.

The aim of this study was to determine the level of anti-hemagglutinin antibodies in blood sera collected from patients during the 2022/2023 epidemic season in Poland. A total of 700 sera samples from patients across the country were tested. The samples were divided into seven groups according to the age of the patients, with 100 samples from each age group.

Influenza vaccination as a prognostic factor of humoral IgA responses to SARS-CoV-2 infection.

There is evidence that influenza vaccination may provide additional benefits by inducing training of innate immunity and increasing humoral responses to heterologous challenges. Immunoglobulin A (IgA) antibodies dominate the early phase of the adaptive response to SARS-CoV-2 infection, but whether their production may be associated with previous influenza vaccination has not been a subject of any study. This study compared serum SARS-CoV-2-specific IgA responses, measured with Microblot-Array assay, in individuals who experienced COVID-19 (N = 1318) and differed in the status of the seasonal influenza vaccine, age, sex, and disease severity.

Prevalence of circulating antibodies against hemagglutinin of influenza viruses in epidemic season 2021/2022 in Poland.

The aim of the study was to determine the level of anti-hemagglutinin antibodies in the serum of patients during the 2021/2022 epidemic season in Poland. A total of 700 sera samples were tested, divided according to the age of the patients into 7 age groups: 0-4 years of age, 5-9 years of age, 10-14 years of age, 15-25 years of age, 26-44 years of age, 45-64 years of age and ≥65 years of age, 100 samples were collected from each age group. Anti-hemagglutinin antibody levels was determined using the haemagglutination inhibition assay (OZHA).