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

Influenza vaccine effectiveness in immunocompromised patients with cancer: A Danish nationwide register-based cohort study

BACKGROUND

Influenza vaccination is free of charge for Danish citizens with acquired immunodeficiency but recommendations do not specifically target patients with cancer. This study investigated whether influenza vaccination reduces the main outcome of overall mortality and the secondary outcomes of influenza requiring treatment, pneumonia, myocardial infarction, stroke, heart failure, and venous thromboembolism in patients with cancer.

METHODS

This was a register-based nationwide cohort study. Adjusted hazard ratios (aHRs) and 95% confidence intervals (95% CIs) for overall mortality and secondary outcomes were estimated using Cox proportional hazards models. Analyses were conducted separately for four subgroups: patients aged <65 years with solid tumors, patients aged ≥65 years with solid tumors, patients aged <65 years with hematological cancer, and patients aged ≥65 years with hematological cancer.

RESULTS

A total of 53,249 adult patients with solid tumors who received chemotherapy and 22,182 adult patients with hematological cancer were followed for up to five influenza seasons in the study period of 2007-2018. In the main analysis covering December-March, influenza vaccination was associated with reduced overall mortality in all four subgroups. The reduction was most pronounced in patients with hematological cancer aged <65 years (aHR, 0.66; 95% CI, 0.51-0.87) and smallest in patients with solid tumors aged <65 years (aHR, 0.91; 95% CI, 0.84-0.99). In sensitivity analyses covering January-March, the aHR was 0.87 (95% CI, 0.65-1.16) in patients with hematological cancer aged <65 years and 1.01 (95% CI, 0.92-1.10) in patients with solid tumors aged <65 years. Results for the secondary outcomes were inconclusive.

CONCLUSIONS

The results of this study cannot reject that influenza vaccination reduces overall mortality in immunocompromised patients with cancer. The results must be interpreted with caution because of potential unmeasured confounding, which can result in the overestimation of influenza vaccine effectiveness.

[Determinants of influenza vaccination in people over 65 years of age: A systematic review]

Low influenza vaccination rates among specific risk groups contribute to the burden of disease and remain a major public health challenge. Therefore, the purpose of this review was to provide the most recent evidence on the determinants of influenza vaccination in people over 65years of age. During the review process, we followed the recommendations for PRISMA systematic reviews. The bibliographic search was carried out in databases Cumulative Index to Nursing and Allied Health Literature (CINAHL), SCOPUS, MedLine / PubMed, Cochrane, Google Scholar, with free and controlled language and the search terms MeSh: Vaccination Coverage, Health Communication, Aged, Influenza Vaccines by combining them with the Boolean operators AND and OR. The search was limited to articles published between 2019-2024. Seven original research articles were included, of which observational and cross-sectional studies were identified as the main type of study. The topic of study represents education, the recruitment of the vulnerable population and the detection of sociodemographic factors that affect vaccination coverage. The findings of this review suggest that it would be beneficial to take into account communication, education and recruitment as determining factors of influenza vaccination in those over 65years of age. In this sense, effective strategies could be implemented to increase vaccination coverage in the most vulnerable population and improve future vaccination campaigns.

Mathematical modeling for estimating influenza vaccine efficacy: A case study of the Valencian Community, Spain

Vaccine efficacy and its quantification is a crucial concept for the proper design of public health vaccination policies. In this work we proposed a mathematical model to estimate the efficacy of the influenza vaccine in a real-word scenario. In particular, our model is a SEIR-type epidemiological model, which distinguishes vaccinated and unvaccinated populations. Mathematically, its dynamics is governed by a nonlinear system of ordinary differential equations, where the non-linearity arises from the effective contacts between susceptible and infected individuals. Two key aspects of this study is that we use a vaccine distribution over time that is based on real data specific to the elderly people in the Valencian Community and the calibration process takes into account that over one influenza season a specific proportion of the population becomes infected with influenza. To consider the effectiveness of the vaccine, the model incorporates a parameter, the vaccine attenuation factor, which is related with the vaccine efficacy against the influenza virus. With this framework, in order to calibrate the model parameters and to obtain an influenza vaccine efficacy estimation, we considered the 2016-2017 influenza season in the Valencian Community, Spain, using the influenza reported cases of vaccinated and unvaccinated. In order to ensure the model identifiability, we choose to deterministically calibrate the parameters for different scenarios and we find the one with the minimum error in order to determine the vaccine efficacy. The calibration results suggest that the influenza vaccine developed for 2016-2017 influenza season has an efficacy of approximately 76.7%, and that the risk of becoming infected is five times higher for an unvaccinated individual in comparison with a vaccinated one. This estimation partially agrees with some previous studies related to the influenza vaccine. This study presents a new integrated mathematical approach to study the influenza vaccine efficacy and gives further insight into this important public health topic.

Incidence and prevalence of headache in influenza: A 2010-2021 surveillance-based study

BACKGROUND AND PURPOSE

Influenza is a common cause of acute respiratory infection, with headache being one of the symptoms included in the European Commission case definition. The prevalence of headache as a symptom of influenza remains unknown. We aimed to describe the incidence and prevalence of headache in patients with influenza.

METHODS

All consecutive patients who met the definition criteria of influenza-like illness during the influenza seasons 2010-2011 through 2021-2022 were included. The seasonal cumulative incidence of influenza per 1000 patients at risk and the prevalence of headache as an influenza symptom were calculated, including the 95% confidence intervals (CIs). Subgroup analyses were done based on patients' sex, age group, microbiological confirmation, vaccination status, and influenza type/subtype/lineage.

RESULTS

During the study period, 8171 patients were eligible. The incidence of headache in the context of influenza varied between 0.24 cases per 1000 patients (season 2020-2021) and 21.69 cases per 1000 patients (season 2017-2018). The prevalence of headache was 66.1% (95% CI = 65.1%-67.1%), varying between 49.6% (season 2021-2022) and 80.1% (season 2010-2011). The prevalence of headache was higher in women (67.9% vs. 65.7%, p = 0.03) and higher in patients between 15 and 65 years old. Headache was more prevalent in patients infected with B subtypes than A subtypes (68.7% vs. 56.9%, p < 0.001). There were no notable differences regarding vaccination status or microbiological confirmation of the infection.

CONCLUSIONS

Headache is a common symptom in patients with influenza, with a prevalence higher than that observed in other viral infections.

COVID-19 vaccine uptake and vaccine hesitancy in rural-to-urban migrant workers at the first round of COVID-19 vaccination in China

BACKGROUND

Migration can be linked to the transmission of COVID-19. COVID-19 vaccine uptake and hesitancy among rural-to-urban migrant workers in China, the largest group of internal migrants in the world, has not been characterized.

OBJECTIVE

To investigate COVID-19 vaccine uptake and identify vaccine hesitancy-associated factors among rural-to-urban migrant workers in the first round of COVID-19 vaccination in China.

METHODS

A cross-sectional questionnaire-based survey was conducted, including 14,917 participants. Socio-demographics, COVID-19 vaccine uptake, vaccine hesitancy and its associated factors based on Vaccine Hesitancy Determinants Matrix (VHDM) were applied for the survey. Data were principally analyzed by logistic regression analysis.

RESULTS

The COVID-19 vaccine uptake and vaccine hesitancy rates were 7.1% and 57.7%, respectively. Vaccine hesitancy was strongly associated with VHDM, including individual factors (female, higher annual income and fewer medical knowledge), group factors (less family support, friend support and public opinion support), COVID-19 epidemic factors (lower fatality, infection and emotional distress) and vaccine factors (less vaccine necessity, vaccine safety, vaccine efficacy, vaccine importance and vaccine reliability).

CONCLUSION

The VHDM model has the potential utility in efforts to reduce COVID-19 vaccine hesitancy. Greater efforts should be put into addressing positive predictors associated with vaccine hesitancy.

Low influenza vaccine uptake by healthcare workers caring for the elderly in South African old age homes and primary healthcare facilities

BACKGROUND

The elderly bear the highest burden of South Africa's estimated annual > 10 million influenza cases and > 11,000 influenza-related deaths. Unvaccinated healthcare workers (HCWs) are at high occupational risk of contracting influenza, and may transmit influenza to elderly patients in their care. Thus, the South African National Department of Health recommends that HCWs receive annual influenza vaccination. This study aimed to determine influenza vaccination coverage among HCWs; identify reasons for their vaccination status; and investigate if HCWs recommend vaccination to their elderly patients.

METHODS

A descriptive study was conducted in 18 community health centres and 44 private sector and non-governmental organisation managed old age homes across South Africa, using a self-administered structured questionnaire, which was distributed to 360 HCWs present on the day of data collection. Data were captured using Microsoft Excel® and imported to Epi Info™ 7 (Centers for Disease Control and Prevention, USA) for descriptive statistical analysis. Ethics approval (SMUREC/P/36/2018: PG) and permission to conduct the study at the facilities were obtained. All participants provided informed consent.

RESULTS

The response rate was 76.7% (276/360). Most participants were female (90.9% [251/276]), nursing professionals (81.2% [224/276]) with a mean age of 41.1 ± 11.7 years. Although 62.7% of participants indicated having ever received at least one dose of the influenza vaccine, influenza vaccine uptake for 2017 and 2018 was 24.36% (41/276) and 33.3% (92/276) respectively. The main reasons given for never being vaccinated against influenza were related to the unavailability of the vaccine (70.9%) and vaccine hesitancy (27.2%). Most participants (67.8% [187/276]) recommended vaccines to elderly patients in their care.

CONCLUSION

The main reasons behind low influenza vaccine uptake by HCWs in South Africa who care for the elderly were related to unavailability of the vaccine and vaccine hesitancy. Strategies to educate HCWs on the importance of influenza vaccination, while concurrently increasing sustained and easy access to the vaccine by HCWs are needed to preserve public health.

Life Satisfaction and Influenza Vaccination Among Older Adults in Canada

Older adults have an increased risk of complications or death from influenza. Despite the benefits of vaccination for older adults, vaccination coverage among older adults ages 65 years and over is still below Canada's national target of 80 per cent. As health-care-seeking behaviours are influenced by several factors, including life satisfaction, we investigated the relationship between life satisfaction and influenza vaccination among older adults. A sample (n = 22,424) from the 2015-2016 Canadian Community Health Survey data was analysed using descriptive and multinomial logistic regression analyses. Higher life satisfaction was associated with a more recent influenza vaccination history. Vaccination differed by gender, age, and self-reported health status, as women, much older adults, and those with the poorest health status were more likely to be vaccinated. The study suggests an association between life satisfaction and influenza vaccination. More research into the factors that impact influenza vaccination in older adults is needed to increase vaccination coverage in the older adult population.

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.

Factors associated with COVID-19 vaccination behaviour in Latvian population: cross-sectional study

Vaccination is the most effective way of limiting the spread of COVID-19. However, despite the proven effectiveness and safety of vaccines, there is resistance in society and the course of vaccination is slow. The aim of this study was to identify the factors associated with COVID-19 vaccination behaviour. Methods: The data originate from a representative sample of Latvian residents (N  = 1017) taken in September 2021. The data were analysed using Chi-squared test, Mann-Whitney test, Spearman's rank correlation coefficient, Kruskal Wallis test, and Binary Logistic regression analysis. Results: The results of the study reveal several factors that are associated with COVID-19 vaccination behaviour. These factors are a higher level of education, motivation for protecting oneself against illness, for promoting collective immunity, protecting relatives and other people from infection, as well as motivation for vaccination in order to keep a job or continue studies, and institutional trust. On the other hand, perceived social support from relatives is negatively associated with vaccination behaviour. Conclusion: A higher level of education and confidence in evidence-based information on COVID-19, provided by official sources of information, is the key factor in deciding whether to protect oneself from serious illness or to make a choice to promote collective immunity and protect other people. The need for vaccination in order to continue working and/or learning is also an essential motive for vaccination. On the other hand, the belief that, if necessary, it is possible to receive support from relatives may be a delaying factor in the behaviour of vaccination.

Predictors of Influenza Vaccination Uptake and the Role of Health Literacy among Health and Social Care Volunteers in the Province of Prato (Italy)

Annual influenza vaccination is recommended for volunteers involved in primary health and social services. Little is known about the volunteers’ adhesion to influenza vaccination recommendations. The aim of this study was to assess influenza vaccination determinants among a group of volunteers who provided essential activities during the first SARS-CoV-2 pandemic wave in the province of Prato, Tuscany (Italy) and to evaluate the role of health literacy in influencing vaccination determinants. Method: In this cross-sectional study, the predictors of influenza vaccination uptake were assessed through the administration of a questionnaire. Variables significantly associated with influenza vaccination uptake were included in five multivariate logistic regression models through a backward stepwise procedure. Results: Among the 502 enrolled volunteers, 24.3% reported being vaccinated in the 2019–2020 season. Vaccination uptake was 48.8% in participants aged 65 years or older and 15.7% in those aged 64 years or younger. Considering the whole sample in the final model of multivariate logistic regression analysis, the predictors of influenza vaccination uptake were age (OR = 1.05; 95% CI = 1.03–1.07), presence of heart diseases (OR = 2.98; 95% CI = 1.24–7.19), pulmonary diseases (OR = 6.18; 95% CI = 2.01–19.04) and having undergone surgery under general anesthesia in the prior year (OR = 3.14; 95% CI = 1.23–8.06). In the multivariate model considering only participants with a sufficient level of health literacy (HL), none of these predictors resulted in significant associations with vaccination uptake, except for age (OR= 1.04; 95% CI = 1.02–1.07). Conclusions: Our findings revealed a very low influenza vaccination uptake among volunteers, suggesting the need to increase awareness in this at-risk group by means of a better communication approach.

Time Trends (2012-2020), Sex Differences and Predictors for Influenza Vaccination Uptake among Individuals with Chronic Obstructive Pulmonary Disease in Spain

(1) Background: To analyze time trends, sex differences, and factors associated with influenza vaccination uptake among individuals with COPD in Spain, 2012−2020. (2) Methods: A cross-sectional study based on data from the European Health Surveys for Spain, 2020 (EHSS2020) and 2014 and from the Spanish National Health Interview Surveys for 2017 and 2012. (3) Results: The study included 65,447 participants. Prevalence of COPD was 5.9% (n = 3855). Overall, the influenza vaccination uptake among COPD patients was 57.8% versus 28.6% for those without COPD (p < 0.001). Men with COPD reported higher uptake than women in all the surveys studied. Neither the crude nor the multivariable analysis showed a significant variation change overtime for people with COPD. However, among those aged <65 years, crude uptake decreased from 2012 to 2020 (39.4% vs. 33.3%; p = 0.039). Over the entire period, men were vaccinated significantly more than women (OR 1.28; 95% CI 1.12−1.47). Among COPD participants, included in the EHSS2020, independent predictors of vaccine uptake included being male, higher age, reporting no current smoking and suffering cancer or heart disease. (4) Conclusions: In COPD patients, the influenza vaccination uptake is below desirable levels and did not improve from 2012 to 2020. Sex differences are found, with consistent and constant lower uptake among women with COPD. The observed lower uptake among COPD women and patients with unhealthy lifestyle requires increased attention.

Knowledge, attitudes, beliefs and barriers of healthcare professionals and adults ≥ 65 years about vaccine-preventable diseases in Spain: the ADult Vaccination drIverS and barriErs (ADVISE) study

Since 2018, Spanish National Immunization Guidelines include vaccination recommendations for adults ≥65 years. To determine whether health-care professionals and the ≥65 years target group value the need for these recommendations, a cross-sectional study was conducted to capture and describe their knowledge, attitudes, beliefs and behaviors about vaccination. Online surveys were administered to representative groups of general practitioners (GPs), primary care nurses and adults ≥65 years from six major cities (and surrounding rural areas) in Spain. Main topics were attitudes and awareness of vaccines, perceptions about vaccination in adults ≥65 years, and impact of the COVID-19 pandemic on vaccination uptake. A total of 286 health-care professionals (185 GPs, 101 nurses) and 400 adults aged ≥65 years participated in the survey. GP and nurse groups agreed strongly about the importance of influenza and pneumococcal vaccination in the target population. Longer patient visit times were identified as a key factor toward promoting vaccination. The ≥65 years sample group, especially those ≥75+ years and/or with chronic diseases, was reasonably positive about the effectiveness and benefits of vaccines. Lower vaccination rates for the pneumococcal than influenza vaccine (29% vs. 80%) in the ≥65 years sample group suggest that efforts are needed to improve pneumococcal vaccine uptake. Aligning with other published works, GPs have a key role in promoting vaccination in the target population. The COVID-19 pandemic appears to have heightened awareness about the importance of vaccination among health-care professionals and adults ≥65 years.

Low Levels of Influenza Vaccine Uptake among the Diabetic Population in Spain: A Time Trend Study from 2011 to 2020

(1) Background: In this work, we aim to describe influenza vaccine uptake among the diabetic population in Spain to assess the time trend from 2011 to 2020 and identify predictors of vaccine uptake among diabetes patients. (2) Methods: We conducted a descriptive cross-sectional study using the European Health Interview Survey for Spain (2014 and 2020) and the Spanish National Health Surveys (2011 and 2017). The independent variables analysed included socio-demographic characteristics, health-related variables and lifestyle variables. We matched each participant with diabetes with a non-diabetic participant based on age, sex, place of residence and year of survey. (3) Results: The overall coverage among diabetic adults was 52.1% compared to 40.6% for matched participants without diabetes (p < 0.01). The vaccine uptake among adults with diabetes was 52.6% in 2011, 54.38% in 2014 and 53.4% in 2017. The adjusted OR of having been vaccinated in 2020, with respect to 2011, was not significant at 0.87 (95% CI: 0.72–1.06). Factors such as being male, higher age, being affected by respiratory disease or cancer and being physically active were identified as positive predictors for influenza vaccination uptake, while smoking was a negative predictor. (4) Conclusions: The influenza vaccine uptake is below desirable levels among the adult diabetic population in Spain and has not improved from 2011 to 2020. More efforts should be made to increase influenza vaccine uptake in this high-risk group, especially for women, those aged 18–64 years, without other high-risk conditions and smokers.

Influenza vaccination uptake among high-risk target groups and health care workers in Spain and change from 2017 to 2020

OBJECTIVE

Using the 2020 European Health Survey for Spain (EHSS2020), which ran from July 2019 to July 2020, we aimed to describe influenza vaccination uptake among the following target groups; individuals aged ≥65 years, health care workers (HCWs), and persons with high-risk chronic medical conditions. We analyzed changes in uptake since the previous Spanish National Health Interview Survey conducted in 2017 and identified variables associated with vaccine uptake.

METHODS

We performed a cross-sectional study. The primary study variable was the self-reported uptake of influenza vaccine in the previous year. We analyzed sex, age, country of birth, and being an HCW. We identified participants with self-reported respiratory diseases, cardiovascular disease, diabetes, cancer, and cerebrovascular diseases. Multivariable logistic regression was applied to assess changes over time and to identify variables associated with vaccination in target groups.

RESULTS

Uptake was 19.2% in 22,072 participants aged ≥15 years. Uptake was 54.4% for those aged ≥65 years, 41.6% for those with a high-risk medical condition, and 26.53% among HCWs. Uptake by disease was 52.1% for cerebrovascular diseases, 51.3% for cardiovascular diseases, 48.3% for diabetes, 46.1% for cancer, and 36.2% for respiratory diseases. No significant improvement has been observed since 2017 in any target group, except for participants with cancer, whose uptake increased from 33.2% to 46.1%(p < 0.001). The variables that significantly increased the probability of reporting vaccine uptake were female sex, age ≥35 years, being born in Spain, self-reported respiratory or cardiovascular diseases, diabetes, cancer, and being a HCW.

CONCLUSIONS

Influenza vaccination uptake among target groups in Spain is below desirable levels and has not improved significantly since 2017. Older age, female sex, and being born in Spain are positive predictors of vaccine uptake. The COVID-19 pandemic highlights the urgent need to implement new strategies to increase influenza vaccine uptake.

Patients' Perception and Knowledge about Influenza and Pneumococcal Vaccination during the COVID-19 Pandemic: An Online Survey in Patients at Risk of Infections

INTRODUCTION

The objective of our study was to assess, in an at-risk population, perception and knowledge about influenza and pneumococcal vaccinations.

METHODS

An anonymous web-based survey was submitted to patients recruited in France, from both an Ipsos internal panel and AVNIR patient associations. The study was conducted between July and October 2020, in the context of the COVID-19 pandemic.

RESULTS

Overall, 2177 questionnaires from patients at risk of infection were analyzed. Almost all respondents (86%, 1869/2177) declared themselves to be favorable to vaccination. Nearly half of the patients (49%, 1069/2177) were aware of which vaccine was recommended for their specific situation. This percentage was significantly (p < 0.001) higher for members of a patient association and for people affected by multiple chronic conditions and varied according to the type of condition. Almost two-thirds of patients (1373/2177) declared having been vaccinated during the 2019/2020 influenza season, and 41% (894/2177) were certain about being up to date with the pneumococcal vaccination. The main barriers to vaccination for influenza are the fear of side effects, doubt regarding the efficacy of the vaccine and for pneumococcal vaccination, and the absence of suggestions by the healthcare professionals (HCPs), as 64% of respondents were not recommended to obtain pneumococcal vaccination. To improve vaccine coverage, information is of prime importance and GPs are recognized as the main HCP to inform about vaccination. Nearly two-thirds (62%, 1360/2177) of patients declared that the COVID-19 pandemic convinced them to have all the recommended vaccines.

CONCLUSION

Our study highlighted the nonoptimal vaccine coverage in at-risk populations despite a highly positive perception of vaccines and confirmed that physicians are on the front lines to suggest and recommend these vaccinations, especially in the current pandemic context, which may be used to promote other vaccines.

The association between the density of vaccination workers and immunization coverage in Zhejiang province, East China

Background: We aimed to evaluate whether the density of vaccination workers was associated with the immunization coverage in Zhejiang province.Methods: The immunization coverage of measles-containing vaccine (MCV), the third dose of diphtheria, tetanus, and pertussis combined vaccine (DTP3), and the third dose of poliomyelitis vaccine (PV3) was selected as the dependent variables. Immunization coverage data of children aged 13-23 months were taken from the Zhejiang immunization information system (ZJIIS). The aggregate density of vaccination workers was an independent variable in one set of regressions, while the full-time and part-time vaccination workers were adopted separately in other sets.Results: The density of total vaccination workers was positively and significantly associated with the immunization coverage (MCV: AOR = 3.36; DTP3: AOR = 2.68; PV3: AOR = 2.37). However, when the effects of full-time vaccination workers and part-time vaccination workers were assessed separately, we only found that the density of full-time vaccination workers was positively and significantly associated with the immunization coverage (MCV: AOR = 5.59; DTP3: AOR = 4.13; PV3: AOR = 3.28). The proportion of migrant children < 7 years and Land area were found as negative and significant factors for immunization coverage.Conclusions: A higher density of vaccination workers could improve the availability of vaccination services and immunization coverage. We recommended that government or other non-government organization should, apart from vaccine-related assistance, focus their efforts on human resources for vaccination.