Hemagglutination inhibition antibody titers as a correlate of protection against influenza disease in the 2018/2019 epidemic season in Poland.

The aim of this study was to determine the level of antibodies against hemagglutinin of influenza viruses in the sera of people in the seven age groups in the epidemic season 2018/2019 in Poland. The level of anti-hemagglutinin antibodies was determined by hemagglutination inhibition test (HAI). 1050 clinical samples from all over the country were tested. The level of antibodies against influenza viruses was highest in the 10-14 age group for A/Singapore/INFIMH-16-0019/2016 (H3N2) and B/Phuket/3073/2013 Yamagata lineage antigens. These results confirm the circulation of four antigenically different influenza virus strains, two subtypes of influenza A virus - A/Michigan/45/2015 (H1N1)pdm09 and A/Singapore/INFIMH-16-0019/2016 (H3N2) and two lineages of influenza B virus - B/Colorado/06/2017 - Victoria lineage and B/Phuket/3073/2013 Yamagata lineage.

Quadrivalent Influenza Vaccine-Induced Antibody Response and Influencing Determinants in Patients ≥ 55 Years of Age in the 2018/2019 Season.

The effects of immunization with subunit inactivated quadrivalent influenza vaccine (QIV) are not generally well assessed in the elderly Polish population. Therefore, this study evaluated vaccine-induced antibody response and its determinants. METHODS: Consecutive patients ≥ 55 years old, attending a Primary Care Clinic in Gryfino, Poland, received QIV (A/Michigan/ 45/2015(H1N1)pdm09, A/Singapore/INFIMH-16-0019/2016 (H3N2), B/Colorado/06/2017, B/Phuket/ 3073/2013) between October-December 2018. Hemagglutination inhibition assays measured antibody response to vaccine strains from pre/postvaccination serum samples. Geometric mean titer ratio (GMTR), protection rate (PR) and seroconversion rate (SR) were also calculated. RESULTS: For 108 patients (54.6% males, mean age: 66.7 years) the highest GMTR (61.5-fold) was observed for A/H3N2/, then B/Colorado/06/2017 (10.3-fold), A/H1N1/pdm09 (8.4-fold) and B/Phuket/ 3073/2013 (3.0-fold). Most patients had post-vaccination protection for A/H3N2/ and B/Phuket/3073/ 2013 (64.8% and 70.4%, respectively); lower PRs were observed for A/H1N1/pdm09 (41.8%) and B/Colorado/06/ 2017 (57.4%). The SRs for A/H3N2/, A/H1N1/pdm09, B Victoria and B Yamagata were 64.8%, 38.0%, 46.8%, and 48.2%, respectively. Patients who received QIV vaccination in the previous season presented lower (p < 0.001 and p = 0.03, respectively) response to B Victoria and B Yamagata. CONCLUSIONS: QIV was immunogenic against the additional B lineage strain (B Victoria) without significantly compromising the immunogenicity of the other three vaccine strains, therefore, adding a second B lineage strain in QIV could broaden protection against influenza B infection in this age group. As the QIV immunogenicity differed regarding the four antigens, formulation adjustments to increase the antigen concentration of the serotypes that have lower immunogenicity could increase effectiveness. Prior season vaccination was associated with lower antibody response to a new vaccine, although not consistent through the vaccine strains.

Occurrence of Influenza Hemagglutinin Antibodies in the Polish Population during the Epidemic Season 2017/18.

This study seeks to define the level of antihemagglutinin antibodies, using the hemagglutination inhibition assay (HAI), in the serum of patients, stratified into seven age groups, in Poland during the influenza epidemic season of 2017/18. A quadrivalent influenza vaccine has been introduced in Poland as of this epidemic season, making it possible for the first time to conduct the analysis for four antigens: A/Michigan/45/2015 (H1N1) pdm09, A/Hong Kong/4801/2014 (H3N2), B/Brisbane/60/2008 - Victoria lineage, and B/Phuket/3073/2013 - Yamagata lineage. We found that the level of individual antihemagglutinin antibodies was different among the seven age groups studied; with the highest in patients of 5-9 years and 10-14 years of age. Interestingly, the protection factor, defined as the percentage of people with the level of antihemagglutinin antibodies of at least 1:40 after vaccination or due to a previous infection, was the highest for the antigen A/Hong Kong/4801/2014 (H3N2) in the same age groups (74% and 75%, respectively). Taking into account the dismal 3.6% of the vaccinated population in Poland, these findings point toward the sustained presence of an immune system response in patients after a prior influenza virus infection.

Influenza in Poland in 2013 and 2013/2014 epidemic season

OBJECTIVE: Analysis of epidemiological situation of influenza in Poland in 2013 and 2013/14 epidemic season in reference to previous years and seasons. MATERIAL AND METHODS: Analysis was based on: 1) data collected within influenza routine surveillance system in Poland, including data published in annual bulletins "Infectious diseases and poisonings in Poland" as well as unpublished data gathered in the Department of Epidemiology of the NIPH-NIH; 2) data collected within influenza system - Sentinel, and beyond this system, concerning results of virological tests carried out in 2013/14 epidemic season in the Department of Influenza Research, National Influenza Center in the NIPHNIH and/or laboratories of provincial sanitary and epidemiological stations which are gathered in the National Influenza Center. RESULTS: Compared to 2012, the number of influenza and influenza-like cases increased more than twofold in 2013 in Poland. A total of 3 164 405 cases were reported. Incidence was 8 218.7 per 100,000 population (33 733.2 in 0-4 age group). As many as 0.45% of patients were referred to hospitals. According to the data of the Central Statistical Office, 115 deaths due to influenza were notified. Based on the data of the sanitary inspection (incomplete data), the percentage of population vaccinated against influenza was 2.4% (7.7% of persons aged more than 64 years). A total of 2 780 945 cases were registered in 2013/14 epidemic season. Its peak was reported in March 2014. Incidence was 7 224.0 per 100,000 population (35 172.8 in 0-4 age group). Compared to 2012/13 epidemic season, it was lower by 8.0%. Incidence rates ranged from 29 339.6 in pomorskie voivodeship to 1 306.5 in lubuskie voivodeship. Nearly a half of all cases (48.7%) were registered in children and adolescents up to 15 years. As many as 0.34% of patients were referred to hospitals (0.87% of persons aged more than 64 years). From the data of the Central Statistical Office transpires that 8 deaths due to influenza were reported in epidemic season. Type A influenza subtype H3N2 predominated in all influenza cases. Human respiratory syncytial virus (RSV) was the dominant agent in other viral infections of respiratory tract. Antigenic analysis of influenza strains showed their affinity with vaccine strains of the vaccine recommended for this epidemic season. CONCLUSIONS: In spite of slow improvements, influenza and influenza-like surveillance system in Poland is still not homogeneous and stable enough. It hinders the assessment of current epidemiological situation. For instance, there are difficulties in determining what is the effect of modifications in the surveillance on the increase in the number of influenza and influenza-like cases observed in Poland in recent years. A low percentage of population vaccinated against influenza (with a decreasing trend beginning from 2005) suggests a necessity of revising the methods of promotion and organization of these vaccines used so far. One of the public health priorities should be to increase the percentage of vaccinated population up to the average level in EU countries.

[Influenza surveillance]. / Nadzór nad grypa.

Influenza surveillance was established in 1947. From this moment WHO (World Health Organization) has been coordinating international cooperation, with a goal of monitoring influenza virus activity, effective diagnostic of the circulating viruses and informing society about epidemics or pandemics, as well as about emergence of new subtypes of influenza virus type A. Influenza surveillance is an important task, because it enables people to prepare themselves for battle with the virus that is constantly mutating, what leads to circulation of new and often more virulent strains of influenza in human population. As vaccination is the most effective method of fighting the virus, one of the major tasks of GISRS is developing an optimal antigenic composition of the vaccine for the current epidemic season. European Influenza Surveillance Network (EISN) has also developed over the years. EISN is running integrated epidemiological and virological influenza surveillance, to provide appropriate data to public health experts in member countries, to enable them undertaking relevant activities based on the current information about influenza activity. In close cooperation with GISRS and EISN are National Influenza Centres--national institutions designated by the Ministry of Health in each country.

Influenza in Poland in 2011-2012 and in 2011/2012 and 2012/2013 epidemic seasons.

UNLABELLED: This paper aimed at evaluating the epidemiological situation of influenza in Poland in 2011-2012 and in 2011/2012 and 2012/2013 epidemic seasons and comparing it with the situation observed in the previous years. MATERIAL AND METHODS: An analysis was mainly based on three sources of data: (1) bulletins "Infectious diseases and poisonings in Poland in 2012" and "Vaccinations in Poland in 2012" (NIPH-NIH, CSI. Warsaw 2013) and analogically former bulletins, (2) "Reports on influenza cases and persons suspected of influenza", sent in 2013 and previous years to the Department of Epidemiology, NIPH-NIH by the Voivodeship Sanitary- Epidemiological Stations, (3) data of the Department of Influenza Research, National Influenza Centre, NIPH- NIH - results of virological testing performed in 2011/2012 and 2012/2013 epidemic seasons in the National Influenza Centre and/or laboratories of the Voivodeship Sanitary-Epidemiological Stations (VSES) within influenza surveillance - Sentinel as well as beyond this system. Data on influenza cases come from aggregated notifications which are sent obligatorily to the VSES by all health care units and physician practices. Influenza, influenza-like illness and acute respiratory infections, i.e. cases meeting the criteria recommended in influenza surveillance in the European Union are subject to mandatory notification. RESULTS: In 2011-2012, there was an increase in the number of influenza and influenza-like illness cases in Poland compared to 2010, i.e. 2- and 2,5-fold, respectively. In 2011, a total of 1 156 357 cases were reported and incidence amounted to 3 001.5 per 100,000 population (11 014.5 in age group 0-4 years). As many as 0.51% of infected persons were referred to hospital. According to the CSO data, 95 fatal cases of influenza were notified. Influenza vaccination coverage was 2.8%. In 2012, 1 460 037 cases were registered and incidence was 3 789.0 (17 807,1 in age group 0-4 years). A total of 0.33% of influenza cases were referred to hospital. As many as 4 deaths due to influenza were reported. Percentage of population vaccinated against influenza amounted to 2.3%. In 2011/12 epidemic season, 1 085 471 cases were noted and incidence was 2 816.6 per 100,000 population (12 792.3 in age group 0-4 years) while in 2012/13 epidemic season its number was nearly 3-fold higher, i.e. 3 025 258 cases and incidence - 7 851.0 (30 591.7 in age group 0-4 years). In both epidemic seasons, type A influenza subtype H1N1 and human respiratory syncytial virus (RSV) predominated in infections with influenza virus and other viral respiratory infections, respectively. Antigenic analysis of influenza strains showed their affinity with vaccine strains of the vaccines recommended for these epidemic seasons. SUMMARY: An increase in the number of notified cases of influenza and influenza-like illness, which is recently observed in Poland, is significantly affected by the improving quality (especially sensitivity) of surveillance system, commenced in the 2009 influenza pandemic. This surveillance system, however, is still not sufficiently uniform and stable. Low percentage of population vaccinated against influenza suggests the ineffectiveness of influenza vaccine promotion campaigns conducted so far. An increase in the influenza vaccination coverage to the average observed in the EU countries should be one of the priorities for the sanitary-epidemiological stations.