Influenza Vaccination Program Research Articles

Using social contact data to improve the overall effect estimate of a cluster-randomized influenza vaccination program in Senegal.

This study estimates the overall effect of two influenza vaccination programs consecutively administered in a cluster-randomized trial in western Senegal over the course of two influenza seasons from 2009-2011. We apply cutting-edge methodology combining social contact data with infection data to reduce bias in estimation arising from contamination between clusters. Our time-varying estimates reveal a reduction in seasonal influenza from the intervention and a nonsignificant increase in H1N1 pandemic influenza. We estimate an additive change in overall cumulative incidence (which was 6.13% in the control arm) of -0.68 percentage points during Year 1 of the study (95% CI: -2.53, 1.18). When H1N1 pandemic infections were excluded from analysis, the estimated change was -1.45 percentage points and was significant (95% CI, -2.81, -0.08). Because cross-cluster contamination was low (0-3% of contacts for most villages), an estimator assuming no contamination was only slightly attenuated (-0.65 percentage points). These findings are encouraging for studies carefully designed to minimize spillover. Further work is needed to estimate contamination - and its effect on estimation - in a variety of settings.

Is there a role for inpatient influenza vaccination programmes?

Patients with chronic liver disease have much higher mortality associated with influenza compared to other risk groups (1). Influenza vaccine uptake is much lower in adults with chronic liver disease (37.3%) compared to adults aged over 65 (72.4%) or other risk groups (44.9%) (2). Hospital-based interventions for inpatients have been shown to increase uptake (3). Vaccination records of patients admitted to a Hepatology ward were reviewed retrospectively to understand what proportion were eligible but did not receive annual influenza vaccine through current services. Data was collected for inpatients 26th September 2020 to 29th November 2020. GP records were used to check vaccination status within the window 01/09/2020 to 28/02/2021. Patients not registered with a local GP or deceased were excluded. We compared the rates of vaccination between at risk groups. 134 were eligible for influenza vaccination and inclusion. 95 (70.9%) were not immunised at the time of admission. 36 (29.1%) went on to be immunised in the same influenza season, leaving 59 (44.0%) of individuals not receiving a vaccine at all. Vaccination rates are below the 75% target. Most patients, who were eligible at the time of admission, never received an influenza vaccination. An inpatient influenza vaccination programme could utilise this missed opportunity to increase vaccine uptake.

People aged 50 to 64 years will not be eligible for NHS flu vaccines in 2022/2023

Free flu vaccines under the 2022/2023 NHS Seasonal Influenza Vaccination Programme will no longer be offered to people aged 50 to 64 years in England, the government has announced. In guidance published on 2 March 2022, the NHS said the flu vaccination programme will be returning to “pre-pandemic recommendations”, meaning that only those aged under […]

Factors associated with intensified infection prevention and vaccination practice among Thai health care personnel: A multicenter survey during COVID-19 pandemic

Intensified infection prevention (IP) and health care personnel (HCP) vaccination programs could enhance HCP safety during COVID-19 pandemic. A multi-center survey regarding on intensified IP practices and vaccination uptake among HCP was performed. Working in the emergency medicine department was associated with wearing a double mask and face shield (P = .04). Despite having more confidence in care of COVID-19 patients, there was no significant improvement of intensified IP practices, COVID-19 and influenza vaccination programs among “high-risk” HCP.

Sequential Delivery of Live Attenuated Influenza Vaccine and Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in the Ferret Model Can Reduce SARS-CoV-2 Shedding and Does Not Result in Enhanced Lung Pathology.

Co-circulation of SARS-CoV-2 and influenza viruses could pose unpredictable risks to health systems globally, with recent studies suggesting more severe disease outcomes in co-infected patients. The initial lack of a readily available COVID-19 vaccine has reinforced the importance of influenza vaccine programmes during the COVID-19 pandemic. Live Attenuated Influenza Vaccine (LAIV) is an important tool in protecting against influenza, particularly in children. However, it is unknown whether LAIV administration influences the outcomes of acute SARS-CoV-2 infection or disease. To investigate this, quadrivalent LAIV was administered to ferrets 3 days pre- or post-SARS-CoV-2 infection. LAIV administration did not exacerbate SARS-CoV-2 disease course or lung pathology with either regimen. Additionally, LAIV administered prior to SARS-CoV-2 infection significantly reduced SARS-CoV-2 replication and shedding in the upper respiratory tract. This study demonstrated that LAIV administration in close proximity to SARS-CoV-2 infection does not exacerbate mild disease and can reduce SARS-CoV-2 shedding.

Evaluation of a city-wide school-located influenza vaccination program in Oakland, California with respect to race and ethnicity: A matched cohort study

BackgroundIncreasing influenza vaccination coverage in school-aged children may substantially reduce community transmission. School-located influenza vaccinations (SLIV) aim to promote vaccinations by increasing accessibility, which may be especially beneficial to race/ethnicity groups that face high barriers to preventative care. Here, we evaluate the effectiveness of a city-wide SLIV program by race/ethnicity from 2014 to 2018. MethodsWe used multivariate matching to pair schools in the intervention district in Oakland, CA with schools in a comparison district in West Contra Costa County, CA. We distributed cross-sectional surveys to measure caregiver-reported student vaccination status and estimated differences in vaccination coverage levels and reasons for non-vaccination between districts stratifying by race/ethnicity. We estimated difference-in-differences (DID) of laboratory confirmed influenza hospitalization incidence between districts stratified by race/ethnicity using surveillance data. ResultsDifferences in influenza vaccination coverage in the intervention vs. comparison district were larger among White (2017–18: 21.0% difference [95% CI: 9.7%, 32.3%]) and Hispanic/Latino (13.4% [8.8%, 18.0%]) students than Asian/Pacific Islander (API) (8.9% [1.3%, 16.5%]), Black (5.9% [−2.2%, 14.0%]), and multiracial (6.3% [−1.8%, 14.3%)) students. Concerns about vaccine effectiveness or safety were more common among Black and multiracial caregivers. Logistical barriers were less common in the intervention vs. comparison district, with the largest difference among White students. In both districts, hospitalizations in 2017–18 were higher in Blacks (Intervention: 111.5 hospitalizations per 100,00; Comparison: 134.1 per 100,000) vs. other races/ethnicities. All-age influenza hospitalization incidence was lower in the intervention site vs. comparison site among White/API individuals in 2016–17 (DID −25.14 per 100,000 [95% CI: −40.14, −10.14]) and 2017–18 (−36.6 per 100,000 [−52.7, −20.5]) and Black older adults in 2017–18 (−282.2 per 100,000 (−508.4, −56.1]), but not in other groups. ConclusionsSLIV was associated with higher vaccination coverage and lower influenza hospitalization, but associations varied by race/ethnicity. SLIV alone may be insufficient to ensure equitable influenza outcomes.

Influenza and morbidity and mortality risk in patients in Mexico with systemic arterial hypertension alone or with comorbidities: a retrospective, observational, cross-sectional study from 2014 to 2020

ObjectivesIn Mexico, patients with systemic arterial hypertension (SAH) are excluded from the influenza vaccination programme despite their risk of cardiovascular events as influenza-related complications. We investigated the impact of influenza...

Development and validation of an algorithm to estimate the risk of severe complications of COVID-19: a retrospective cohort study in primary care in the Netherlands

ObjectiveTo develop an algorithm (sCOVID) to predict the risk of severe complications of COVID-19 in a community-dwelling population to optimise vaccination scenarios.DesignPopulation-based cohort study.Setting264 Dutch general practices contributing to the...

Vaccination in pregnancy against pertussis and seasonal influenza: key learnings and components from high-performing vaccine programmes in three countries: the United Kingdom, the United States and Spain

BackgroundPertussis and seasonal influenza are responsible for significant maternal, neonatal, and infant morbidity and mortality, but vaccine coverage rates (VCR) for both pertussis (administered as a tetanus, diphtheria, acellular pertussis [Tdap] vaccination) and seasonal influenza in pregnancy remain generally low. Only a small number of countries, including Spain, the United Kingdom (UK), and the United States (US), have high Tdap and seasonal influenza VCRs in pregnancy. The purpose of this study was to identify the key factors that contributed to the high VCRs observed in these countries.MethodsThe experience from both Tdap and seasonal influenza vaccination programmes during pregnancy were documented in Spain, the UK, and the US using a three-step approach. A literature review yielded 157 publications, and a further 117 documents were selected through desk research. A published five-pillar VCR framework for influenza was amended to evaluate the specific contributing factors leading to high Tdap and seasonal influenza VCRs among pregnant women.ResultsThe analysis identified components that contributed to higher VCR in pregnant women across three different healthcare systems in Spain, UK, and US. The combination of several key interventions in each country led to a rapid increase in VCR that reached near-optimal levels (i.e. 75% for seasonal influenza) within a few years. As well as inclusion in national immunisation programme and vaccine reimbursement, key components that were identified included the mobilisation of health authorities, prenatal care Healthcare Professionals (HCP) and scientific societies, the inclusion of vaccination in antenatal medical guidance, the provision of educational material to HCPs, and a strong disease awareness driven by recent pertussis outbreaks in each country.ConclusionsAlthough there is no simple, universal solution to improving sub-optimal VCRs, the list of components identified in this study from three countries with high-performing Tdap and seasonal influenza vaccination programmes provides a basis for public health and medical stakeholders in other countries to define strategies to successfully implement national vaccination programmes for pregnant women.

Cost-effectiveness of seasonal influenza vaccination in pregnant women, healthcare workers and adults >= 60 years of age in Lao People’s Democratic Republic

BackgroundPregnant women, healthcare workers (HW), and adults >= 60 years have shown an increased vulnerability to seasonal influenza virus infections and/or complications. In 2012, the Lao People's Democratic Republic (Lao PDR) initiated a national influenza vaccination program for these target groups. A cost-effectiveness evaluation of this program was undertaken to inform program sustainability. MethodsWe designed a decision-analytical model and collected influenza-related medical resource utilization and cost data, including indirect costs. Model inputs were obtained from medical record abstraction, interviews of patients and staff at hospitals in the national influenza sentinel surveillance system and/or from literature reviews. We compared the annual disease and economic impact of influenza illnesses in each of the target groups in Lao PDR under scenarios of no vaccination and vaccination, and then estimated the cost-effectiveness of the vaccination program. We performed sensitivity analyses to identify influential variables. ResultsOverall, the vaccination of pregnant women, HWs, and adults >= 60 years could annually save 11,474 doctor visits, 1,961 days of hospitalizations, 43,027 days of work, and 1,416 life-years due to laboratory-confirmed influenza illness. After comparing the total vaccination program costs of 23.4 billion Kip, to the 18.4 billion Kip saved through vaccination, we estimated the vaccination program to incur a net cost of five billion Kip (599,391 USD) annually. The incremental cost per life-year saved (ICER) was 44 million Kip (5,295 USD) and 6.9 million Kip (825 USD) for pregnant women and adults >= 60 years, respectively. However, vaccinating HWs provided societal cost-savings, returning 2.88 Kip for every single Kip invested. Influenza vaccine effectiveness, attack rate and illness duration were the most influential variables to the model. ConclusionProviding influenza vaccination to HWs in Lao PDR is cost-saving while vaccinating pregnant women and adults >= 60 is cost-effective and highly cost-effective, respectively, per WHO standards.

Influenza hospitalizations in Australian children 2010-2019: The impact of medical comorbidities on outcomes, vaccine coverage, and effectiveness.

BackgroundChildren with comorbidities are at greater risk of severe influenza outcomes compared with healthy children. In Australia, influenza vaccination was funded for those with comorbidities from 2010 and all children aged <5 years from 2018. Influenza vaccine coverage remains inadequate in children with and without comorbidities.MethodsChildren ≤16 years admitted with acute respiratory illness and tested for influenza at sentinel hospitals were evaluated (2010–2019). Multivariable regression was used to identify predictors of severe outcomes. Vaccine effectiveness was estimated using the modified incidence density test‐negative design.ResultsOverall, 6057 influenza‐confirmed hospitalized cases and 3974 test‐negative controls were included. Influenza A was the predominant type (68.7%). Comorbidities were present in 40.8% of cases. Children with comorbidities were at increased odds of ICU admission, respiratory support, longer hospitalizations, and mortality. Specific comorbidities including neurological and cardiac conditions increasingly predisposed children to severe outcomes. Influenza vaccine coverage in influenza negative children with and without comorbidities was low (33.5% and 17.9%, respectively). Coverage improved following introduction of universal influenza vaccine programs for children <5 years. Similar vaccine effectiveness was demonstrated in children with (55% [95% confidence interval (CI): 45; 63%]) and without comorbidities (57% [(95%CI: 44; 67%]).ConclusionsComorbidities were present in 40.8% of influenza‐confirmed admissions and were associated with more severe outcomes. Children with comorbidities were more likely experience severe influenza with ICU admission, mechanical ventilation, and in‐hospital morality. Despite demonstrated vaccine effectiveness in those with and without comorbidities, vaccine coverage was suboptimal. Interventions to increase vaccination are expected to reduce severe influenza outcomes.

Association of weather, air pollutants, and seasonal influenza with chronic obstructive pulmonary disease hospitalization risks

The influences of weather and air pollutants on chronic obstructive pulmonary disease (COPD) have been well-studied. However, the heterogeneous effects of different influenza viral infections, air pollution and weather on COPD admissions and re-admissions have not been thoroughly examined. In this study, we aimed to elucidate the relationships between meteorological variables, air pollutants, seasonal influenza, and hospital admissions and re-admissions due to COPD in Hong Kong, a non-industrial influenza epicenter. A total number of 507703 hospital admissions (i.e., index admissions) and 301728 re-admission episodes (i.e., episodes within 30 days after the previous discharge) for COPD over 14 years (1998–2011) were obtained from all public hospitals. The aggregated weekly numbers were matched with meteorological records and outdoor air pollutant concentrations. Type-specific and all-type influenza-like illness positive (ILI+) rates were used as proxies for influenza activity. Generalized additive models were used in conjunction with distributed-lag non-linear models to estimate the associations of interest. According to the results, high concentrations of fine particulate matter, oxidant gases, and cold weather were strong independent risk factors of COPD outcomes. The cumulative adjusted relative risks exhibited a monotone increasing trend except for ILI+ B, and the numbers were statistically significant over the entire observed range of ILI+ total and ILI+ A/H3N2 when the reference rate was zero. COPD hospitalization risk from influenza infection was higher in the elderly than that in the general population. In conclusion, our results suggest that health administrators should impose clean air policies, such as strengthening emissions control on petrol vehicles, to reduce pollution from oxidant gases and particulates. An extension of the influenza vaccination program for patients with COPD may need to be encouraged: for example, vaccination may be included in hospital discharge planning, particularly before the winter epidemic.

Influenza vaccination 2021–22: increasing uptake and optimising vaccination clinics

Gemma Harris discusses strategies to increase vaccine uptake as the UK undertakes its largest influenza vaccination programme ever, amid a global pandemic.

Programme costs for introducing age/gestation-based universal influenza vaccine schedules for young children and pregnant women in Hong Kong

BackgroundHong Kong experiences year-round influenza activity with winter and summer peaks. The government’s Vaccination Subsidy Scheme (VSS) provides vaccine to high-risk groups prior to the larger winter peak. The VSS is predominantly administered through the private sector. This study aimed to cost the two theoretical routine influenza vaccination schedules using both northern and southern hemisphere vaccines, administered according to child’s age and women’s gestation, from a governmental perspective; and compare these costs to the costs of government’s seasonal VSS assuming equivalent coverage estimates to determine the budget impacts of these influenza vaccination programmes in Hong Kong. MethodsWe used the World Health Organization’s Flutool Plus to estimate the incremental annual costs for immunising young children aged 6 months to 2 years and pregnant women with influenza vaccine during 2021, assuming the latter group accesses the public system for some antenatal care. Inputs were based on literature review, publicly available data and expert opinions. Sensitivity analyses were done with various coverage rates and vaccine costs. ResultsThe annual incremental cost (including vaccine price) to vaccinate young children with three doses of influenza vaccine during the first two years of life was estimated at USD 1,175,146 (per-dose-cost of USD 10.55) at 75% coverage while that to vaccinate pregnant women with one dose at 60% coverage was estimated at USD 398,555 (per-dose-cost of USD 13.39). Across a range of sensitivity analyses we predict that routine year-round schedules could be cost-saving to the government compared to the VSS. Implementing routine immunisation to both risk groups equates to USD 1,573,701, i.e., 0.012% of Hong Kong’s annual healthcare spending. ConclusionProposed year-round universal schedules providing influenza immunisation according to the child’s age or the woman’s gestation are predicted to be cost-saving compared to the current seasonally administered subsidised vaccine programme.

Estimated Cost Effectiveness of Influenza Vaccination for Emergency Medical Services Professionals.

IntroductionBecause of their frequent contact with compromised patients, vaccination against influenza is recommended for all healthcare workers. Recent studies suggest that vaccination decreases influenza transmission to patients and reduces worker illness and absenteeism. However, few emergency medical services (EMS) agencies provide annual vaccination, and the vaccination rate among EMS personnel remains low. Reticence among EMS agencies to provide influenza vaccination to their employees may be due in part to the unknown fiscal consequences of implementing a vaccination program. In this study, we sought to estimate the cost effectiveness of an employer-provided influenza vaccination program for EMS personnel.MethodsUsing data from published reports on influenza vaccination, we developed a cost-effectiveness model of vaccination for a hypothesized EMS system of 100 employees. Model inputs included vaccination costs, vaccination rate, infection rate, costs associated with absenteeism, lost productivity due to working while ill (presenteeism), and medical care for treating illness. To assess the robustness of the model we performed a series of sensitivity analyses on the input variables.ResultsThe proportion of employees contracting influenza or influenza-like illness (ILI) was estimated at 19% among vaccinated employees compared to 26% among non-vaccinated employees. The costs of the vaccine, consumables, and employee time for vaccination totaled $44.19 per vaccinated employee, with a total system cost of $4,419. Compared to no vaccination, a mandatory vaccination program would save $20,745 in lost productivity and medical costs, or $16,325 in net savings after accounting for vaccination costs. The savings were 3.7 times the cost of the vaccination program and were derived from avoided absenteeism ($7,988), avoided presenteeism productivity losses ($10,303), and avoided medical costs of treating employees with influenza/ILI ($2,454). Through sensitivity analyses the model was verified to be robust across a wide range of input variable assumptions. The net monetary benefits were positive across all ranges of input assumptions, but cost savings were most sensitive to the vaccination uptake rate, ILI rate, and presenteeism productivity losses.ConclusionThis cost-effectiveness analysis suggests that an employer-provided influenza vaccination program is a financially favorable strategy for reducing costs associated with influenza/ILI employee absenteeism, presenteeism, and medical care.

Influenza Vaccination Programs for Healthcare Personnel: Organizational Issues and Beyond.

Healthcare personnel (HCP) are a high priority group for influenza vaccination aiming to protect them but also to protect vulnerable patients and healthcare services from healthcare-associated influenza and HCP absenteeism. Multi-component influenza vaccination programs targeting behavioral, organizational, and administrative barriers are critical, if influenza vaccination rates among HCP are to be raised on a sustained basis. Mandatory influenza vaccination policy is the only single intervention that can achieve high and sustainable vaccination rates in HCP in short term. In this article, we provide an overview of issues pertaining to influenza vaccination of HCP, with an emphasis on organizational issues of influenza vaccination programs.

A Mixed-Methods Study to Evaluate Elementary School Staff's Acceptability, Delivery Challenges, and Communication Regarding the Implementation of School-Located Influenza Vaccination Program in Hong Kong.

This was a mixed-methods study comprising a questionnaire-based survey, a qualitative study, and analysis of school newsletters to evaluate elementary school staff’s acceptability, delivery challenges and communication about school-located influenza vaccination program (SIVP) in Hong Kong. We found that school staff with lower intention to implement SIVP perceived greater logistical difficulties in arranging SIVP. Challenges regarding program delivery included schools’ limited infrastructure, the burden of paperwork, the fear of being overwhelmed by multiple school-based vaccination schedules, lacking confidence in communicating with parents about influenza vaccines, and the difficulties in managing vaccination-related anxiety among children with intellectual disability. School staff were generally passive in communicating with parents and students about influenza vaccines. We also found that schools may use the school newsletters as a substitute of the formal informed consent forms. Good partnerships among government, service providers and schools should be established to minimize the burden of paperwork for school staff, facilitate early planning of SIVP, and support schools with limited infrastructure and the vaccination of children with intellectual disabilities. Training is needed to enhance school staff’s confidence in communicating with parents and students about influenza vaccines and improve information delivery to support parents’ informed decisions for children’s vaccination.

Effectiveness of influenza vaccination for school-age children in preventing school absenteeism in Shenzhen: an empirical study

Objective: To assess the impact of vaccination at school and influenza vaccination rates among school-age children on school absenteeism in Shenzhen. Methods: The study subjects were primary school students in Shenzhen. School absenteeism panel database from December 2017 to June 2020 of 286 primary schools in Shenzhen was merged with vaccination rates and organizational patterns (i.e., vaccination at school vs. non-school) data of 9 districts in Shenzhen after influenza vaccination for children. The outcome was the number of school absenteeism. The treatment and control groups were distinguished by organizational patterns and district vaccination rates. Difference-in-Difference (DiD) Poisson regressions were used to analyze the effectiveness of vaccination at school and higher vaccination rates. Besides, a robustness test was performed on the regression results. Results: Poisson regression analysis and robustness test of regression results showed that vaccination at school and higher vaccination rates effectively reduced the risk of school absenteeism, with effectiveness against absenteeism of 32.6% (95%CI: 17.0%-45.3%, P<0.01) and 53.0% (95%CI: 42.1%-61.8%, P<0.01), respectively. Conclusion: A free influenza vaccination program for school-age children in Shenzhen and prioritizing school-based vaccination may be an effective measure to reduce the risk of school absenteeism.

A rapid global review of strategies to improve influenza vaccination uptake in Australia

ABSTRACT This study aimed to identify effective strategies for improving the uptake of influenza vaccination and to inform recommendations for influenza vaccination programs in Australia. A rapid systematic review was conducted to assimilate and synthesize peer-reviewed articles identified in PubMed. The National Health and Medical Research Council (NHMRC) Hierarchy of Evidence was used to appraise the quality of evidence. A systematic search identified 4373 articles and 52 that met the inclusion criteria were included. The evidence suggests influenza vaccination uptake may be improved by interventions that (1) increase community/patient demand and access to influenza vaccine and overcome practice-related barriers; (2) reinforce the critical role healthcare providers play in driving influenza vaccination uptake. Strategies such as standing orders, reminder and recall efforts were successful in improving influenza vaccination rates. Community pharmacies, particularly in regional/remote areas, are well positioned to improve influenza vaccine coverage. The findings of this rapid review can be utilized to improve the performance of influenza immunization programs in Australia and other countries with comparable programs; and recommend priorities for future evaluation of interventions to improve influenza vaccination uptake.

173 Predicted Impact of an Emergency Department Influenza Vaccine Program

Seasonal influenza is associated with significant healthcare resource utilization. An estimated 490,000 hospitalizations and 34,000 deaths were attributed to influenza during the 2018 – 2019 season. Despite robust influenza vaccination programs in both the inpatient and outpatient setting, the emergency department (ED) represents a missed opportunity to vaccinate patients at high risk for influenza who do not have access to routine preventive care. Feasibility and implementation of ED-based influenza vaccination programs have been previously described but have stopped short of describing the predicted health resource impact.