Target Group For Influenza Vaccination Research Articles

Influenza vaccine hesitancy among healthcare workers in a Northeastern province in Thailand: Findings of a cross-sectional survey

Background Healthcare workers (HCWs) are an important target group for influenza vaccination due to their increased risk of infection. However, their uptake remains a challenge. This study aimed to identify and measure influenza vaccine hesitancy among HCWs in Nakhon Phanom province, Thailand. Methods A representative cross-sectional survey was conducted during August–September 2020, among 350 HCWs at six hospitals in the province selected by a two-stage cluster sampling using a self-administered questionnaire. HCWs who either delayed getting influenza vaccines, accepted the vaccines but were unsure, or refused the vaccine with doubts were categorized as hesitant. HCWs who accepted the influenza vaccine without any doubts were classified as non-hesitant. Determinants of vaccine hesitancy were identified by a multivariable logistic regression analysis. Results A total of 338 participants (97%) filled the questionnaires. The mean age of the participants was 37.2 years. Most participants were female (280; 83%), nurses (136; 40%), working at district hospitals (238; 71%), with bachelor’s degree (223; 66%), and without any pre-existing chronic medical conditions (264; 78%). Influenza vaccine hesitancy was evident among nearly 60% of the participants (197/338), who had varying patterns of hesitancy. Significant factors of influenza vaccine hesitancy were found to be age above 50 years (adjusted odds ratio [aOR] 3.2, 95% CI 1.3–8.5), fair knowledge of influenza and vaccination (aOR 0.4, 95% CI 0.2–0.8), and negative influence of other HCW (High level–aOR 2.3, 95% CI 1.1–4.8; Moderate level- aOR 2.1, 95% CI 1.1–4.4). Conclusion Influenza vaccine hesitancy was highly prevalent among the Thai HCWs in Nakhon Phanom province. Imparting updated information to the HCW, in combination with positive guidance from influential HCWs in the hospital, may help reduce hesitancy. These data may be useful to the National Immunization Program to design appropriate approaches to target hesitant HCWs in Thailand to improve influenza vaccine coverage.

Efficacy and safety of a quadrivalent influenza vaccine in children aged 6–35 months: A global, multiseasonal, controlled, randomized Phase III study

BackgroundChildren are an important target group for influenza vaccination, but few studies have prospectively evaluated influenza vaccine efficacy (VE) in children under 3 years of age. This was a randomized Phase III trial to assess the efficacy, immunogenicity, and safety of an inactivated quadrivalent influenza vaccine (QIV) in young children (EudraCT: 2016–004904–74). MethodsInfluenza-naïve children aged 6–35 months were randomized during three influenza seasons to receive vaccination with QIV or a non-influenza control vaccine. One group of participants was revaccinated with QIV in the subsequent influenza season. The primary efficacy endpoint was the absolute VE of QIV against influenza caused by any circulating strain. Key secondary efficacy endpoints included the absolute VE of QIV against influenza due to antigenically matching strains and immunogenicity. Safety and reactogenicity were also evaluated. ResultsIn total, 1005 children received QIV and 995 received control vaccine. Influenza A/B infection due to any circulating influenza strain occurred less frequently in children who received QIV versus children receiving a control vaccine. The absolute VE of QIV against any circulating influenza strain was 54% (95% confidence interval [CI]: 37%, 66%). The absolute VE of QIV against antigenically matching influenza strains was 68% (95% CI: 45%, 81%). Mean hemagglutination inhibition titers for all influenza strains in the QIV group increased post-vaccination, whereas increases were minimal in the control vaccine group; results from virus neutralization and neuraminidase-inhibition assays were generally consistent with the hemagglutination inhibition assay findings. Approximately 12 months after primary vaccination with QIV, antibody titers remained higher than pre-vaccination titers for most strains. In participants who were revaccinated, QIV elicited strong antibody responses. The overall safety profile and reactogenicity of QIV was comparable with control vaccine. ConclusionPrimary vaccination with QIV was well tolerated and effective in protecting children aged 6–35 months against influenza.

Association between Serum Antibody Titers against Influenza Viruses and the Risk of Influenza in Patients with Chronic Respiratory Diseases - a Prospective, Longitudinal Study

Introduction: Patients with respiratory co-morbidities are the primary target group for influenza vaccination as chronic respiratory diseases pose a serious risk for unvaccinated individuals during influenza season. According to Centers for Disease Control and Prevention (CDC) guidelines, serum antibody titer of ≥ 40 is associated with “at least a 50% decrease in risk of acquiring influenza infection”. Methods: A prospective, longitudinal study was conducted in 345 patients with chronic respiratory diseases (April 2014-August 2015). Serum samples were tested for antibody levels against influenza A and B viruses using hemagglutination inhibition assay as per WHO protocol. These patients were followed up for one year and nasopharyngeal swab was collected from any patient who reported Influenza-like illness symptoms and subjected to real-time PCR for influenza viruses. Results: The seroprotective rates against influenza A (H1N1) pdm09, influenza A(H3N2), influenza B (Victoria and Yamagata) were 61%, 94%, 61%, 68% respectively. During the follow-up period of one year, 5 cases of influenza A/H3N2 and 7 cases of influenza B infection were identified while there were no cases of influenza A(H1N1)pdm09 infection. One case of influenza A/H3N2 infection was observed in an individual who had protective titers against the same virus while all 7 cases of influenza B infection occurred in people with non-protective titers against both the strains of influenza B viruses. Conclusion: Based on the findings of this study, it is proposed that in patients with chronic respiratory diseases influenza vaccination may be considered after more concrete information is obtained on correlates of protection against influenza subtypes.

Influenza immunization among Tunisian health care workers in the 2018-2019 influenza season

Abstract Background Given the nature of their activities, health care workers (hcws) are at higher risk of contracting influenza and transmitting the disease to their patients. Influenza vaccine (IV) remains the most effective way to prevent influenza and its complications. To the best of our knowledge, no national data on IV coverage among hcws is available in Tunisia. The present study aimed to assess the flu vaccination coverage among Tunisian hcws in the 2018-2019 influenza season and factors associated with IV uptake through a study of knowledge and attitudes related to influenza vaccination. Methods A cross sectional study was conducted in Tunisian primary and secondary health care facilities from March to May 2019. Hcws with direct patient contact were recruited according to a self-weighted multistage sampling. Survey data collection was based on a face to face questionnaire containing both open and closed questions. Results A total of 1231 hcws were enrolled in this study. Among respondents, 15.3% (95% CI: [12.3-17.2]) were vaccinated against influenza during the 2018-2019 influenza season. High confidence regarding vaccine efficacy (OR = 3.5, 95%CI: 2.5-4.8), belief that hcws' influenza immunization may decrease illness and deaths among patients (OR = 1.7, 95% CI: 1.2-2.3) and belief that influenza vaccination can reduce work absenteeism (OR = 1.7, 95% CI: 1.2-2.4) were associated with a higher IV uptake among hcws. In addition, participants who mentioned hcws as a target group for influenza vaccination (OR = 2.0, 95% CI: 1.5-2.8) and who were agree that IV is indicated annually for hcws (OR = 3.1, 95% CI: 1.9-4.9) were more likely to receive the IV. Conclusions Influenza vaccination coverage among Tunisian health professionals in 2018-2019 was low. Our findings suggest that knowledge and attitudes regarding influenza vaccine influence vaccine compliance among hcws and should thus be targeted by vaccination campaigns to promote flu vaccine uptake in the health community. Key messages Vaccination coverage among Tunisian healthcare workers was low in the 2018-2019 influenza season. Our findings suggest that knowledge and attitudes regarding influenza vaccine influence vaccine uptake among Tunisian health care workers.

A community-based survey on influenza and vaccination knowledge, perceptions and practices in Peru

BackgroundAlthough Peru provides safe and effective influenza vaccines free-of-charge, coverage among vaccine target groups like pregnant women and older adults remains low. To improve risk communication messages and vaccine uptake, we explored knowledge, perceptions and practices about influenza illness and vaccination. MethodsA cross-sectional, community-based survey with a three-stage cluster sampling design was conducted in three cities in Peru. We included mothers of young children, pregnant women and persons ≥65 years. Participants completed a questionnaire about knowledge, perceptions and practices about influenza illness and vaccination against influenza during the past year. Generalized linear models were used to explore factors associated with vaccination in the past year. Results624/645 (97%) mothers, 54/55 (98%) pregnant women and 622/673 (92%) older adults approached provided informed consent and were surveyed. While most mothers, pregnant women and older adults (94%, 96% and 91%, respectively) perceived influenza as a potentially serious illness, few pregnant women (13%) and older adults (34%) self-identified themselves as a target group for influenza vaccination. Only 28% of mothers, 19% pregnant women, and 27% older adults were vaccinated against influenza during the previous year. Among the participants that did not get vaccinated against influenza in the previous year, “being afraid of vaccination and its effects” was the most commonly cited barrier. Knowledge of the recommendation for annual vaccination was significantly associated with vaccination status among pregnant women (p = 0.048) and older adults (p = 0.004). ConclusionDespite a government subsidized vaccine program, vaccine utilization remained low among pregnant women and older adults, who seemed typically unaware of their status as high-risk groups targeted for vaccination. Those aware of the recommendations for annual vaccination were more likely to be vaccinated. Information campaigns addressing fears and highlighting populations at risk for severe influenza illness that are targeted for vaccination might increase vaccine coverage in Peru.

Influenza vaccine uptake in the elderly population: Individual and general practitioner’s determinants in Central Italy, Lazio region, 2016–2017 season

BackgroundElderly people are a priority target group for influenza vaccination and their decision to be vaccinated might partly depend on advice received from general practitioners (GP). This study aims to investigate the association between influenza vaccine uptake in the elderly residents in the Lazio region of Italy and the demographic and professional characteristics of their GPs, taking simultaneously into account the elderly’s individual characteristics. MethodsWe used data retrieved from different administrative sources to retrospectively analyse the cohort of 1,255,657 elderly residents aged ≥65 years who were alive and registered in the regional healthcare service at the beginning of the 2016–2017 influenza vaccination campaign (1 Oct. 2016–31 Jan. 2017). We assessed influenza vaccine uptake at the end of the vaccination campaign and evaluated its association with both individual and GP-related characteristics through a multilevel Poisson regression models accounting for clustering at physician level. ResultsOverall, vaccination coverage at the end of vaccination campaign was 50.6%. Elderly residents who were male, older, vaccinated in the previous seasons, living in smaller provinces, and spending more money for specialist medical care showed a significantly increased probability to be vaccinated. Vaccine uptake was also significantly higher in the elderly residents assisted by GPs who got master’s degree more recently, assisted a relatively high proportion of elderly patients, received influenza vaccination, had a computer assistant, and were associated with other physicians. ConclusionsOur results indicate that influenza vaccination coverage in the elderly residents of the Lazio region is still unsatisfactorily low. We identified several determinants of influenza vaccine uptake, related to both individual and GP characteristics. Understanding how GP characteristics affected influenza vaccine uptake in the elderly population might provide insight on GPs’ attitudes and concerns regarding influenza vaccination, allowing the implementation of targeted evidence-based interventions to sensitise GPs and increase vaccination coverage.

Influenza vaccination among nursing students from a university of Castilla-León for the 2014-2015 season after their inclusion as target group for vaccination

Trainee students in healthcare settings of Castilla-León have been included as target group for influenza vaccination since 2012-2013 season. Our aim was to determine vaccination coverage against seasonal influenza virus among nursing students and to identify its determining factors after the implementation of such indication. An analytical cross-sectional study was performed during the 2014-2015 school year. It included all enrolled nursing students from a university of Castilla-León. The information (2014-2015 influenza vaccination status, reasons and 10 questions about knowledge of vaccines) was obtained by a self-administered questionnaire. Absolute and relative frequencies were calculated and the associations were evaluated using a Chi-square test and logistic regression. 227 students of the 340 (66.8%) completed the questionnaire. 5.3% of them reported having been vaccinated. The main reasons to be vaccinated were: self-protection (75%), protection of family/friends (58.3%) and protection of patients (50%). The main reasons to be unvaccinated were: nobody has offered to vaccinate me (59.2%) and not having risk of influenza or its complications (40.8%). At least 8 knowledge questions were answered correctly by 22.0% of students. Being aware that vaccines components are not dangerous was associated with vaccination (p=0.023). The coverage was low regarding rates in health-care workers. Therefore, it is necessary to develop strategies to promote and raise awareness regarding vaccination in this group. The level of knowledge was improvable. Since the knowledge that the doses of chemical substances in vaccines are not dangerous was associated with vaccination, specific educational programs should be carried out at universities to improve/reinforce the students' knowledge regarding vaccines.

Implementation of the influenza vaccination recommendation in nursing homes in Germany : results of a survey as part of the national influenza immunization campaign

Residents and staff of nursing homes are important target groups for influenza vaccination in Germany. The aim of this study was to gain the first insights into whether nursing homes organize activities with respect to vaccination against influenza and whether there is a demand for further information. In the context of the national influenza immunization campaign-which is jointly carried out by the Robert Koch Institute (RKI) and the Federal Centre for Health Education (BZgA) on an annual basis-influenza information kits were sent to the management of 10,700 nursing homes in September 2013. Along with the information material, the institutions also received a questionnaire to which they were able to respond via mail, fax, or online. Data from 988 homes were included in the analysis. The majority of institutions informed both residents (88.9 %) and nursing staff (81.2 %) about influenza vaccination. However, only 64.7 % of nursing homes carried out specific immunization activities for their residents and only half (49.3 %) offered a flu shot to their staff. When asked why the institutions do not provide influenza-specific information and vaccination to their staff, the majority had the opinion that this is the responsibility of each individual's general practitioner. Overall, only 4.9 % of nursing homes assessed influenza vaccination coverage among their staff annually. A third of all surveyed institutions (33.6 %) expressed a demand for additional influenza vaccine-related information. In conclusion, improved health education is needed to raise awareness about the importance of influenza vaccination among residents and employees of nursing homes in Germany so as to prevent influenza-associated morbidity and mortality in this risk group.

Examining the views of key stakeholders regarding the provision of occupational influenza vaccination for healthcare workers in Australia

Annual vaccination of hospital healthcare workers (HCWs) may be an effective measure to reduce the transmission of healthcare associated influenza. However, vaccine coverage rates among HCWs in most public Australian hospitals are below satisfactory for a number of reasons. This study aimed to examine the opinions of key health stakeholders on current issues regarding HCW influenza vaccination.A qualitative study involving semi-structured interviews was undertaken with key Australian health stakeholders representing different organizations and sectors involved in influenza vaccination and policy. Amongst the participants, there was overwhelming support for HCW influenza vaccination. They viewed vaccination as one of the most important preventive measures for healthcare associated influenza and generally agreed that vaccination of HCWs reduces the overall risk of transmission to patients. However, there were contradictory attitudes regarding the evidence available for justifying the impact of vaccinating HCWs against influenza. Amongst the stakeholders interviewed, there was support for continuing to promote influenza vaccination for HCWs via the conventional framework. Participants recommended that hospitals continue to use conventional, voluntary strategies to increase vaccine coverage such as education and mobile carts. Given that the World Health Organization has included HCWs as a target group for influenza vaccination, Australian hospitals may need to start considering the use of mandatory policies in the near future.

Targeted vaccine selection in influenza vaccination.

The main target groups for influenza vaccination are the elderly, the chronically ill, infants, and toddlers. Influenza vaccines are needed that suit the immunological particularities of each of these age and risk groups. Recent years have seen the approval of influenza vaccines that are more immunogenic than before, but whose use in Germany is limited by the restriction of reimbursement to a small number of vaccines. The Medline database was selectively searched for pertinent literature. The suboptimal immunogenicity of conventional influenza vaccines that contain inactivated viral cleavage products and subunits can be markedly improved by the use of squalene-based adjuvant systems, by the integration of viral antigens in virosomal particles, or by intradermal administration. The vaccination of elderly persons with a vaccine containing the adjuvant MF59 was found to lower the risk of hospitalization for influenza or pneumonia by 25% compared to vaccination with a trivalent inactivated vaccine (TIV). On the other hand, the adjuvant ASO3 was found to be associated with an up to 17-fold increase in the frequency of narcolepsy among 4- to 18-year-olds. In a prospective study, a virosomal vaccine lowered the frequency of laboratory-confirmed influenza in vaccinated children by 88% compared to unvaccinated children (2 versus 18 cases per 1000 individuals). A live, attenuated influenza vaccine lowered the rate of disease in children up to age 7 by 48% compared to a TIV (4.2% versus 8.1%). The newer vaccines possess improved efficacy when used for primary and booster immunization in certain age and risk groups, and they are superior in this respect to conventional vaccines based on viral cleavage products and subunits. The risk/benefit profiles of all currently available vaccines vary depending on the age group or risk group in which they are used.

Influenza vaccination in India: Position paper of Indian Academy of Pediatrics, 2013

Burden of Influenza is significantly higher in developing countries as compared to developed countries, but the data on the disease burden is less well defined in most of the developing countries including India, and consequently, constraints evolving strategies for prioritization of measures to prevent and control it. The swine flu or A(H1N1) pandemic is on the wane but the virus continues to circulate causing sporadic outbreaks even in 2013. The A(H1N1)pdm09 has replaced the previous circulating seasonal A (H1N1) virus and acquired the status of a seasonal virus. Limited influenza activity is usually seen throughout the year in India with a clear peaking during the rainy season. The rainy season in the country lasts from June to August in all the regions except Tamil Nadu where it occurs from October to December. IAP recommends the ideal time for offering influenza vaccines is just before the onset of rainy season. The efficacy/effectiveness data of trivalent inactivated influenza vaccines are also presented in different age groups and different categories of individuals. The IAP maintains its earlier recommendations of using the current trivalent inactivated influenza vaccine in all children with risk factors but not as a universal measure. IAP has now prioritized different target groups for influenza vaccination based on contribution of the group to the overall influenza burden, disease severity, and vaccine effectiveness in different age groups and categories. The current trivalent inactivated influenza vaccines incorporate the 2009 pandemic strain also, hence avert the need of a separate A (H1N1) vaccine. IAP stresses the need of more refined surveillance; large scale studies on effectiveness of seasonal influenza vaccines in Indian children, and more effective, properly matched, higher-valent influenza vaccines.

Saisonale und pandemische Influenzaimpfung: Impfquoten und Einstellung niedergelassener Ärzte in Deutschland

General practitioners serve as important multipliers for seasonal influenza vaccination in risk groups such as elderly or chronically ill persons, for whom vaccination is recommended in Germany by the Standing Committee on Vaccination (STIKO). Moreover, physicians are a target group for influenza vaccination themselves. Data from 1 590 telephone interviews were analysed. The study population comprised private physicians from 4 different disciplines (general and internal medicine, gynaecology, paediatrics). We assessed seasonal and pandemic vaccination coverage, attitudes and informational needs related to vaccination in general, and opinions about the pandemic situation 2009. Of the interviewed physicians, 61% stated that they have been vaccinated against seasonal influenza regularly. Main reasons for not/only occasionally having received a flu shot were: the belief that seasonal influenza vaccination is not necessary for them (78%) or having forgotten about the vaccination (28%). The interviewed physicians expressed a great demand for active information on STIKO recommendations and certain aspects of the seasonal influenza vaccination. There was a significant association between physicians' own influenza vaccination status and the provision of vaccination information materials, utilisation of a data management system for the vaccination of patients, and active vaccination reminders in the physicians' office. In 2009/10, almost 60% had received a pandemic influenza A(H1N1) vaccination. A major barrier to vaccine uptake was the mistrust in the safety of H1N1 vaccines (stated by 54% of non-vaccinees). Information for the public and physicians by the German public health authorities during the pandemic was rather critically appraised by the respondents. Compared to other subgroups of health-care workers, among private physicians seasonal and pandemic vaccine uptake was rather high. The physicians' need for more information on vaccination topics can be met by intensified publishing and communication activities of STIKO and by using existing physician-information channels.

Safety and immunogenicity of an AS03-adjuvanted A(H1N1)pmd09 vaccine administered simultaneously or sequentially with a seasonal trivalent vaccine in adults 61 years or older: Data from two multicentre randomised trials

During the 2009–2010 Northern Hemisphere influenza season, both seasonal and pandemic influenza vaccines were expected to be administered to elderly people, which is an important target group for influenza vaccination. Two multicentre randomised clinical studies were conducted in participants aged ≥61 years to assess the immunogenicity and reactogenicity following vaccination with two doses of an AS03-adjuvanted A(H1N1)pmd09 vaccine when either sequentially administered (21 days before first dose [N=73] or 21 days after second dose [N=72]) or co-administered (first dose [N=84] or second dose [N=84]) with a licensed trivalent seasonal influenza vaccine (TIV). Overall, 313 participants from 2 centres in Sweden (ClinicalTrials.gov, NCT00968890) and 6 centres in Germany (NCT00971425) were randomised to one of the four treatment groups. The AS03-adjuvanted A(H1N1)pmd09 vaccine elicited a good immune response against A(H1N1)pmd09-like virus in all treatment groups after the first and second dose, meeting and exceeding the European licensing criteria for pandemic influenza vaccines. After one dose of the AS03-adjuvanted A(H1N1)pmd09 vaccine, haemagglutination inhibition seroconversion rates ranged from 85% (95% confidence interval: 74–93%) to 93% (85–97%), seroprotection rates from 87% (76–94%) to 96% (90–99%) and geometric mean fold rise from 15 (11–19) to 20 (16–25). The haemagglutination inhibition immune responses to the AS03-adjuvanted A(H1N1)pmd09 vaccine seemed lower when TIV was administered 3 weeks before, while immune responses to TIV seemed not affected by either vaccination schedule. Solicited symptoms were more frequently reported following administration of the AS03-adjuvanted A(H1N1)pmd09 vaccine compared to TIV, but these were mainly mild to moderate in intensity and transient in the four treatment groups. These results suggest that sequential or co-administration of the AS03-adjuvanted A(H1N1)pmd09 vaccine and TIV induced a good immune response to both vaccines and had a clinically acceptable safety profile in people aged ≥61 years.

Efetividade da vacina antigripal na época 2010-2011 em Portugal: Resultados do projeto EUROEVA

Objective: The objectives the EuroEVA study (Influenza vaccine effectiveness in Europe) were to estimate the effectiveness of the seasonal influenza vaccine (VE) in 2010-2011 in the general population and among individuals 65 years of age and older. Study type: An observational study using the case-control and screening methods Local: Continental Portugal Population: The Portuguese population with no contraindications for influenza vaccination Methods: Two study designs were used to estimate Vaccine Effectiveness (VE): the case-control test-negative design and the screening method. In the test-negative design, influenza-like illness cases (ILI) with laboratory confirmation of infection by the influenza virus were compared with the influenza-like illness cases negative for infection by the influenza virus. The influenza VE was estimated as 1 minus the odds ratio of being vaccinated among the cases versus the controls and adjusted for con- founding by logistic regression. In the screening method, the influenza vaccine coverage of the ILI positive cases was compared with coverage estimated in the general population.The influenza VE was estimated using the Orenstein formula and adjusted for confounding by the Farrington method. Results: The results show that the effectiveness of the influenza vaccine in 2010-2011 was 79% (CI95% 43-94) using the test- negative design and 70% (95%CI 32%-87%) using the screening method. After adjusting for confounders, the VE decreased re- spectively to 58% (95%CI -61%-89%) and 64% (95%CI 17%-84%). Conclusions: The estimates of the influenza vaccine effectiveness obtained by the two methods were similar and are within the values published in other studies conducted during the 2010-2011 season. The present study was unable to estimate the VE in the target groups for influenza vaccination. These results strengthen the need for international multicentre studies with a common protocol such as I-MOVE (Monitoring influenza vaccine efectiveness during influenza seasons and pandemics in the European Union).

Incidence of H1N1 2009 Virus Infection through the Analysis of Paired Plasma Specimens among Blood Donors, France

BackgroundKnowledge of the age-specific prevalence of seroprotection and incidence of seroconversion infection is necessary to complement clinical surveillance data and statistical models. It provides the basis for estimating the future impact of influenza A (H1N1pdm09) and implementing appropriate prevention and response strategies.MethodsUsing a cross-sectional design, two-stage stratified sampling and paired plasma samples, we estimated the age-specific prevalence of a protective level of H1N1pdm09 antibodies in the French adult population before and after the 2009/10 pandemic, and the proportion of those susceptible that seroconverted due to infection, from a single sample of 1,936 blood donors aged 20–70 years in mainland France in June 2010. Samples with a haemagglutination inhibition (HI) titre ≥1∶40 were considered seropositive, and seroconversion due to infection was defined as a 4-fold increase in titre in the absence of H1N1pdm09 vaccination or pre-pandemic seropositivity.ResultsOut of the 1,936 donors, 1,708 were included in the analysis. Seroprevalence before the pandemic was 6.7% (95% CI 5.0, 8.9) with no significant differences by age-group (p = 0.3). Seroprevalence afterwards was 23.0% (95% CI 17.7, 29.3) with 20–29 year olds having a higher level than older groups (p<0.001). Seroconversion due to infection was 12.2% (95% CI 6.9, 20.5). Younger age-group, vaccination against H1N1 and being seropositive before the pandemic were strongly associated with post-pandemic seropositivity.ConclusionsBefore the 2009/2010 winter influenza season, only 6.7% of the French mainland population aged 20–70 had a level of antibodies usually considered protective. During the first pandemic wave, 12.2% of the population seroconverted due to infection and the seroprevalence after the wave rose to 23%, either due to prepandemic seropositivity, infection or vaccination. This relatively low latter figure contributed to an extension of target groups for influenza vaccination for the 2010/2011 season.

Estimated Costs Associated with Improving Influenza Vaccination for Health Care Personnel in a Multihospital Health System

Health care personnel (HCP) are an important target group for influenza vaccination because of their close contact with vulnerable patients. Annual influenza vaccination for HCP is recommended to reduce the spread of influenza and decrease staff illness and absenteeism. UPMC Health System, the largest health system in western Pennsylvania, established a quality improvement project to increase influenza vaccination among its > 50,000 employees by implementing survey-informed interventions. At the completion of the intervention, estimates were prepared of the costs associated with implementing a multifaceted quality improvement intervention to improve HCP influenza vaccination rates in a large multihospital health system. All 11 participating hospitals provided education and publicity regarding influenza vaccination and provided vaccine free of charge at mass vaccination clinics. Two additional strategies-mobile vaccination carts and incentives-were implemented in a factorial design such that the hospitals had either carts, incentives, both strategies, or neither. The minimum and maximum costs per vaccinated employee by type of intervention were estimated using cost data for vaccine/supplies, labor, incentives, and administration. The average costs per vaccinated employee ranged from $24.55 to $30.43 for incentives and carts, $20.66 to $25.57 for incentives, $23.24 to $26.54 for carts, and $18.03 to $20.60 for education and publicity only. Vaccination rates increased significantly but remained below ideal levels. Influenza vaccination rates among nonphysician HCP can be improved using various interventions at a low cost per vaccinated employee. The costs for these nonmandatory interventions were modest compared with the costs typically associated with influenza-related absenteeism.

An analysis of national target groups for monovalent 2009 pandemic influenza vaccine and trivalent seasonal influenza vaccines in 2009-10 and 2010-11

BackgroundVaccination is generally considered to be the best primary prevention measure against influenza virus infection. Many countries encourage specific target groups of people to undertake vaccination, often with financial subsidies or a priority list. To understand differential patterns of national target groups for influenza vaccination before, during and after the 2009 influenza pandemic, we reviewed and analyzed the country-specific policies in the corresponding time periods.MethodsInformation on prioritized groups targeted to receive seasonal and pandemic influenza vaccines was derived from a multi-step internet search of official health department websites, press releases, media sources and academic journal articles. We assessed the frequency and consistency of targeting 20 different groups within populations which are associated with age, underlying medical conditions, role or occupations among different countries and vaccines. Information on subsidies provided to specific target groups was also extracted.ResultsWe analyzed target groups for 33 (seasonal 2009 and 2009-10 vaccines), 72 (monovalent pandemic 2009-10 vaccine) and 34 (seasonal 2010 and 2010-11 vaccines) countries. In 2009-10, the elderly, those with chronic illness and health care workers were common targets for the seasonal vaccine. Comparatively, the elderly, care home residents and workers, animal contacts and close contacts were less frequently targeted to receive the pandemic vaccine. Pregnant women, obese persons, essential community workers and health care workers, however, were more commonly targeted. After the pandemic, pregnant women, obese persons, health care and care home workers, and close contacts were more commonly targeted to receive the seasonal vaccine compared to 2009-10, showing continued influence from the pandemic. Many of the countries provided free vaccines, partial subsidies, reimbursements or national health insurance coverage to specific target groups and over one-third of the countries offered universal subsidy regarding the pandemic vaccine. There was also some inconsistency between countries in target groups.ConclusionsDifferences in target groups between countries may reflect variable objectives as well as uncertainties regarding the transmission dynamics, severity and age-specific immunity against influenza viruses before and after vaccination. Clarification on these points is essential to elucidate optimal and object-oriented vaccination strategies.

Risk groups and other target groups – preliminary ECDC guidance for developing influenza vaccination recommendations for the season 2010-11

Providing guidance on risk and target groups for seasonal influenza immunisation is difficult for the 2010-11 season since there is no experience with the new influenza A(H1N1) virus in its seasonal form. Arguments exist for offering immunisation to people with chronic illness and older people, and also for other risk and target groups including pregnant women. A more rigorous approach is being developed to produce annual evidence-based guidance on risk and target groups for influenza vaccination.

Studio costo-efficacia della vaccinazione influenzale per gli italiani di età compresa tra 50 e 64 anni

Background In 1999, the American Academy of Family Physicians already included, among target groups for influenza vaccination, subjects aged 50–64 years, because of the increased prevalence of people with high-risk conditions in this age group. However, studies on the cost-effectiveness and cost-utility of influenza vaccination in this population are necessary in order to provide useful indications for Public Health decision makers.

Target groups for influenza vaccination

Target groups for influenza vaccination