Factors associated with vaccine hesitancy against COVID-19 among adults in Europe: a descriptive study analysis applying socio-ecological framework

OBJECTIVE

This study aimed to explore the factors associated with COVID-19 vaccine hesitancy in Europe among adults by using the Socio-Ecological Model.

RESULTS

This cross-sectional study used secondary data collected from respondents residing in 27 EU countries at the time of May 2021. The outcome was vaccine hesitancy against COVID-19, and the total sample size of 23,606 was analysed by binary logistic regression, as well as McKelvey and Zavonoia's R2. After adding each level of variables, the model found the significant and increased association with vaccine hesitancy in younger age groups (21-39 years and 40-60 years vs. 65 years+), who left full-time education at a young age (16-19 years), those with manual jobs, those with children at home, individuals residing in small towns, and beliefs related to the vaccine. Together, the levels explained 49.5% of the variance associated with vaccine hesitancy, and the addition to each variable layer increased the variance. This highlights the need to consider broad factors at multiple levels to enhance vaccine acceptance and uptake.

Influenza vaccination in older adults and patients with chronic disorders: A position paper from the Portuguese Society of Pulmonology, the Portuguese Society of Diabetology, the Portuguese Society of Cardiology, the Portuguese Society of Geriatrics and Gerontology, the Study Group of Geriatrics of the Portuguese Society of Internal Medicine, and the Portuguese Society of Infectious Diseases and Clinical Microbiology

Influenza affects millions of people worldwide each year and can lead to severe complications, hospitalizations, and even death, especially among vulnerable populations such as older adults and those with chronic medical conditions. Annual vaccination is considered the most effective measure for preventing influenza and its complications. Despite the widespread availability of influenza vaccines, however, vaccination coverage rates remain suboptimal in several countries. Based on the latest scientific evidence and expert opinions on influenza vaccination in older people and patients with chronic disease, the Portuguese Society of Pulmonology (SPP), the Portuguese Society of Diabetology (SPD), the Portuguese Society of Cardiology (SPC), the Portuguese Society of Geriatrics and Gerontology (SPGG), the Study Group of Geriatrics of the Portuguese Society of Internal Medicine (NEGERMI-SPMI), and the Portuguese Society of Infectious Diseases and Clinical Microbiology (SPDIMC) discussed best practices for promoting vaccination uptake and coverage and drew up several recommendations to mitigate the impact of influenza. These recommendations focus on the efficacy and safety of available vaccines; the impact of influenza vaccination on older adults; patients with chronic medical conditions, namely cardiac and respiratory conditions, diabetes, and immunosuppressive diseases; and health care professionals, optimal vaccination timing, and strategies to increase vaccination uptake and coverage. The resulting position paper highlights the critical role that vaccinations play in promoting public health, raising awareness, and encouraging more people to get vaccinated.

Drivers of and barriers to routine adult vaccination: A systematic literature review

We performed a systematic literature review in PubMed and Embase (2016-2021) to investigate the drivers of and barriers to routine vaccination in adults aged 50 and older globally. A thematic assessment identified three categories across 61 publications: sociodemographic, health-related, and attitudinal. The most common sociodemographic determinants (factors identified in studies; n = 47) associated with vaccination uptake were economic status, age, education, and household composition, which had mixed effects on vaccine uptake. For health-related determinants (n = 27), individuals with comorbidities and health care consumption were the most common factors, both increased vaccine uptake. The most common attitudinal factors (n = 42) were self-efficacy, provider or other's recommendations, and vaccine-preventable disease awareness; across studies, all attitude factors had a positive effect, unlike the sociodemographic and health status categories. Findings suggest that patient and provider awareness and education campaigns are effective ways to increase uptake of routine vaccinations in older adults.

No effect modification of influenza virus vaccine effectiveness by age or chronic condition was observed in the 2010/11 to 2017/18 seasons

PURPOSE

Most European influenza vaccine strategies target individuals at higher risk of complications, which include, among others, individuals aged ≥65 years and with chronic conditions. These individuals not only have a high-risk of post-infection complications but also could have lower capacity of acquiring adequate vaccine-induced protection. As such, chronic conditions and age could modify the effect of vaccines. This study aimed at assessing the potential effect modification of influenza vaccine effectiveness (IVE) by age and chronic conditions.

METHODS

We used eight-season data from the Portuguese vaccine effectiveness study. Every season, physicians at primary care units recruited patients with influenza-like illness. Clinical data and swabs were collected for Reverse Transverse Polymerase Chain Reaction (RT-PCR) detection of influenza. Trivalent inactivated IVE was estimated as 1 - odds ratio (OR) of being vaccinated in cases (RT-PCR positive for influenza) versus negative controls. ORs were obtained using a multivariable conditional logistic regression model, paired by week of onset within each season. Confounders were assessed by designing a specific causal diagram. Age (< 65 or ≥65 years) and chronic conditions (diabetes, cardiovascular disease, chronic renal disease, chronic hepatic disease, obesity, chronic respiratory disease, and congenital or acquired immunodeficiency) were studied as effect modifiers by including an interaction term in the regression models. Significance was established at 5%.

RESULTS

Point estimates indicate a higher IVE in the chronic condition strata compared to that in the no chronic condition strata. Regarding age, different results were obtained considering the virus type and (sub)type. When comparing the ≥65 years with the <65 years of age strata, we observed a higher IVE against A(H1N1)pdm09, an equal IVE against A(H3N2) and a lower IVE against B virus. However, all interaction terms were statistically insignificant, and this may be due to a small sample size.

CONCLUSION

The potential effect modification of age or chronic condition was not observed within our study.

Fatores determinantes na adesão à vacina contra influenza em pessoas idosas de um município do interior de Mato Grosso do Sul

Resumo Objetivo Identificar os fatores sociodemográficos, de saúde e de conhecimento sobre a vacinação relacionados à adesão de pessoas idosas à vacina contra influenza no ano de 2019, em um município do interior de Mato Grosso do Sul, Brasil. Método Estudo quantitativo e transversal, realizado com 172 indivíduos com 60 anos ou mais, usuários de serviços de saúde e convivência. Aplicou-se um questionário que contemplou dados sociodemográficos, de saúde e de conhecimento sobre vacinação, além da questão sobre a adesão vacinal na campanha de 2019. Utilizou-se regressão log-linear e redes bayesianas de aprendizado para analisar os dados. Resultados Houve predomínio de pessoas idosas do sexo feminino, com companheiro, entre 60-69 anos de idade e ensino fundamental. A taxa de adesão vacinal contra influenza foi 91,28% em 2019. Os idosos com doenças neuropsiquiátricas, que costumavam receber a vacina anualmente e que tinham recebido nos anos de 2018, 2016 e 2015 tiveram maior prevalência de adesão vacinal em 2019 no modelo de regressão. As redes bayesianas para adesão vacinal em 2019 evidenciaram que saber que existe o Programa Nacional de Imunização leva a pessoa idosa a confiar no mesmo, o que culmina na adesão anual à vacina. Conclusão Os profissionais de saúde e meios de comunicação devem fornecer informações válidas para que as pessoas conheçam e confiem no Programa Nacional de Imunização. O trabalho de orientação dos idosos para vacinação contra influenza deve ser anual, já que é importante que o idoso receba a vacina todos os anos para que mantenha a adesão vacinal.

Trends, Coverage and Influencing Determinants of Influenza Vaccination in the Elderly: A Population-Based National Survey in Spain (2006-2017)

Influenza is a significant public health problem and the elderly are at a greater risk of contracting the disease. The vaccination coverage of the elderly is below the Spanish target of 65% for each influenza season. The aims of this study were to report the coverage of influenza vaccination in Spain among the population aged ≥65 years and high-risk groups for suffering chronic diseases, to analyze the time trends from 2006 to 2017 and to identify the factors which affect vaccination coverage. A nationwide cross-sectional study was conducted including 20,753 non-institutionalized individuals aged ≥65 years who had participated in the Spanish National Health Surveys in 2006, 2011/2012, and 2017. Sociodemographic, health-related variables, and influenza vaccination data were used. A logistic regression analysis was performed to determine the variables associated with influenza vaccination. Influenza vaccination coverage was 60%. By chronic condition, older people with high cholesterol levels and cancer had the lowest vaccination coverage (62.41% and 60.73%, respectively). This coverage declined from 2006 to 2017 in both groups. Higher influenza vaccination was associated with males, Spanish nationality, normal social support perceived, polypharmacy, worse perceived health, participation in other preventive measures, and increasing age and the number of chronic diseases.