Circulation of Antibodies Against Influenza Virus Hemagglutinins in the 2014/2015 Epidemic Season in Poland

Hemagglutinin Antibodies in the Polish Population during the 2019/2020 Epidemic Season

The aim of the study was to determine the level of antibodies against hemagglutinin of influenza viruses in the serum of subjects belonging to seven different age groups in the 2019/2020 epidemic season. The level of anti-hemagglutinin antibodies was tested using the hemagglutination inhibition (HAI) test. The tests included 700 sera from all over Poland. Their results confirmed the presence of antibodies against the following influenza virus antigens: A/Brisbane/02/2018 (H1N1)pdm09 (48% of samples), A/Kansas/14/2017/ (H3N2) (74% of samples), B/Colorado/06/ 2017 Victoria line (26% of samples), and B/Phuket/3073/2013 Yamagata line (63% of samples). The level of antibodies against hemagglutinin varied between the age groups. The highest average (geometric mean) antibody titer (68.0) and the highest response rate (62%) were found for the strain A/Kansas/14/2017/ (H3N2). During the epidemic season in Poland, only 4.4% of the population was vaccinated.

Antibodies to Influenza Virus Hemagglutinin in the 2016/2017 Epidemic Season in Poland

The aim of the study was to determine the level of antibodies against hemagglutinin of influenza viruses in the sera of 1,050 patients stratified into 7 different age groups during the 2016/2017 epidemic season in Poland. The method consisted of using the hemagglutination inhibition test (HAI). The findings confirmed the presence of anti-hemagglutinin antibodies against the following influenza virus antigens: A/California/7/2009 (H1N1) pdm09, A/Hong Kong/4801/2014 (H3N2), and B/Brisbane/60/2008. The level of anti-hemagglutinin antibodies differed across the age groups investigated, with the highest values in patients aged 10-14 years. We also found that the protection factor was highest for B/Brisbane/60/2008 antigen. It amounted to 72.7% in 10-14-year olds and to 69.3% in both 15-25 and 26-44-year olds. Taking into account a dismally low percentage of vaccinated population in the 2016/2017 epidemic season in Poland, amounting to barely 3.33%, the findings should be interpreted as representing the patients' immune system response to influenza virus infection.

Circulation of Influenza Virus in the 2015/2016 Epidemic Season in Poland: Serological Evaluation of Anti-hemagglutinin Antibodies

The diagnostic of influenza virus infections is possible using molecular biology methods as well as the analysis of anti-hemagglutinin (anti-HA) antibodies in the blood serum. The aim of this study was to determine the level of anti-HA antibodies in 7 age groups of patients during the 2015/2016 epidemic season in Poland. A total of 1050 serum samples were tested using the hemagglutination inhibition (HAI) assay. We confirmed the presence of anti-HA antibodies for the influenza virus strains: A/California/7/2009(H1N1)pdm09, A/Switzerland/9715293/2013(H3N2), and B/Phuket/3073/2013, which were the components of the influenza vaccine for the 2015/2016 epidemic season. The level of specific anti-HA antibodies was different in each age group. The geometric mean titers were highest at age 5-9 years, where the antibody protection level reached 61.3% against B/Phuket/3073/2013 and 52.7% for A/Switzerland/9715293/2013(H3N2) antigen. The antibody level amounted to 56.7% against for antigen B at age 45-64. In the remaining age groups, the protection levels for all hemagglutinin types did not exceed 50%. These findings confirm the urgent need to increase a persistently low influenza vaccination coverage in the Polish population, which may have had its part in the noticeable increase in the confirmed cases of influenza and influenza-like virus infection during the season.