Determinants of vaccination uptake, and influenza vaccine effectiveness in preventing deaths and hospital admissions in the elderly population; Treviso, Italy, 2014/2015-2016/2017 seasons

Vaccine uptake, associated factors and reasons for vaccination status among the South African elderly; findings and next steps

OBJECTIVES

The elderly are particularly prone to complications from a number of vaccine-preventable diseases. However, there are limited data on vaccine uptake for this vulnerable population in South Africa. Consequently, this study investigated influenza, pneumococcal and shingles vaccine uptake among elderly people in South Africa; reasons for their vaccination status; and factors associated with their uptake.

METHODS

Cross-sectional study using an interviewer-administered questionnaire to survey 985 consenting adults aged ≥65 years in 2018. Participants were recruited from across South Africa. Bivariate analysis was used to identify socio-demographic variables associated with vaccine uptake, with multivariate logistic regression analysis used to identify key factors associated with vaccine uptake.

RESULTS

Influenza vaccine uptake was 32.3% (318/985), with uptake highest in those aged 85-90 years. Pneumococcal and shingles vaccine uptake was 3.8% (37/985) and 0.4% (4/985) respectively, being highest among those aged >90 years. The strongest statistically significant predictors for influenza vaccination were previous influenza vaccination (OR: 8.42 [5.61-12.64]); identifying as 'Coloured' (OR: 8.39 [3.98-17.69]); and residing in Gauteng Province (OR: 5.44 [3.30-9.02]). The strongest statistically significant predictors of receiving pneumococcal vaccination included receiving influenza vaccination (OR = 10.67 [3.27-37.83]); residing in the Western Cape Province (OR: 7.34 [1.49-36.22]); identifying as 'Indian' (OR: 5.85 [2.53-13.55]); and having a university education (OR: 5.56 [1.25-24.77]). Statistically significant barriers to receiving influenza vaccination included following the Traditional African religion (OR: 0.08 [0.01-0.62]) and residing in Limpopo Province (OR: 0.16 [0.04-0.71]). The main reasons for non-vaccination were considering influenza as a mild illness (36.6%; 242/661), and lack of knowledge about the pneumococcal (93.4%; 886/948) and shingles (95.2%; 934/981) vaccines.

CONCLUSION

Vaccine uptake for all vaccines was sub-optimal, with multiple non-modifiable factors predicting vaccine uptake. These pre-COVID-19 data provide a baseline for measuring the effectiveness of future interventions to increase vaccine uptake and safeguard the health of the elderly.

Pneumococcal vaccine uptake among high-risk adults and children in Italy: results from the OBVIOUS project survey

BACKGROUND

Streptococcus pneumoniae infections, including Invasive Pneumococcal Diseases (IPDs), pose a substantial public health challenge, causing significant morbidity and mortality, especially among children and older adults. Vaccination campaigns have played a vital role in reducing pneumococcal-related deaths. However, obstacles related to accessibility and awareness might impede optimal vaccine adoption. This study aims to provide comprehensive data on pneumococcal vaccine coverage and attitudes within at-risk groups in Italy, with the goal of informing public health strategies and addressing vaccination barriers.

METHODS

Between April 11 and May 29, 2022, a questionnaire investigating vaccine uptake and attitudes toward several vaccinations was administered to 10,000 Italian adults, chosen through population-based sampling. Respondents who were targets of the campaign according to the 2017-2019 National Vaccination Plan, accessed questions regarding pneumococcal vaccination. Data on uptake, awareness of having the right to free vaccination, opinion on vaccine safety, concern with pneumococcal disease, and ease of access to vaccination services were summarized and presented based on statistical regions. Multinomial logistic regression analysis was used to explore factors influencing vaccine uptake.

RESULTS

Out of 2357 eligible adult respondents (42.6% women; mean age: 58.1 ± 15.7), 39.5% received pneumococcal vaccination. Uptake differed among at-risk groups: respondents aged ≥65 (33.7%), with lung disease (48.4%), cardiovascular disease (46.6%), and diabetes (53.7%). Predictors of not being vaccinated and unwilling to included female gender, residing in rural areas, lower education, low concern about pneumococcal disease, vaccine safety concerns, and associations with vaccine-opposed acquaintances. Health access issues predicted willingness to be vaccinated despite non-vaccination. Pneumopathy, heart disease, diabetes, and living in Northeastern or Central Italy were linked to higher uptake. Among the 1064 parents of eligible children, uptake was 79.1%. Parental unawareness of children's free vaccination eligibility was a predictor of non-vaccination. Vaccine safety concerns correlated with reluctance to vaccinate children, while perceived healthcare access challenges were associated with wanting but not having received vaccination.

CONCLUSIONS

Pneumococcal vaccination uptake within prioritized groups and children in Italy remains inadequate. Scarce awareness of vaccine availability and obstacles in accessing vaccinations emerge as principal barriers influencing this scenario.

Excess hospitalizations and in-hospital mortality associated with seasonal influenza in Italy: a 11-year retrospective study

BACKGROUND

Influenza and flu-like syndromes are difficult to monitor because the symptoms are not specific, laboratory tests are not routinely performed, and diagnosis codes are often lacking or incompletely registered in medical records. This may result in an underestimation of hospital admissions, associated costs, and in-hospital mortality. Therefore, this study aimed to estimate the public health and economic burden of hospitalisations associated with influenza in Italy, at the national and regional levels.

METHODS

This 11-year retrospective study included patients admitted to hospitals for influenza or diagnoses associated with influenza (including respiratory and cardiocirculatory conditions) from 2008/09 to 2018/19. Data on hospitalisations were extracted from the Italian Hospital Discharge Records. Information on weekly influenza-like syndrome incidence and weekly average temperature were used to estimate the burden of influenza in terms of hospital admissions in every Italian region and for different age groups by applying a negative binomial model. The model was also applied to estimate in-hospital mortality and the total costs of influenza and influenza-like hospital admissions.

RESULTS

Over the study period, in addition to 3,970 average seasonal admissions coded as influenza, we estimated an average of 21,500 excess hospitalization associated with influenza per season, which corresponds to 36.4 cases per 100,000. Most of the excess hospitalisations concerned older individuals (> 65 years) and children (0-4 years) with 86 and 125 cases per 100,000, respectively. Large variations were observed across regions. Overall, the total estimated hospital burden associated with influenza (including respiratory and cardiocirculatory conditions) was approximately €123 m per year. While the in-hospital mortality for admissions with a primary diagnosis of influenza was very low (~ 150 cases per season), cases increased dramatically for primary diagnoses of influenza and pneumonia (about 9,500 cases per season). The average seasonal in-hospital deaths attributable to influenza were equal to 2,775 cases.

CONCLUSIONS

Our findings suggest a remarkable underestimation of the burden of influenza, mostly in the older population but not neglectable in younger individuals. Our results may aid the management of current and future flu seasons and should be used for policy making (e.g., vaccine strategies) and operation management choices (e.g., planning and staffing beds during influenza peaks). Overall, the present study supports the need for increased testing for influenza in Italy to tackle the current underestimation of influenza burden.

Association of Influenza Vaccination and Dementia Risk: A Meta-Analysis of Cohort Studies

BACKGROUND

Dementia is a critical global public health problem. Previous cohort studies have found that influenza vaccination can decrease the risk of dementia.

OBJECTIVE

This meta-analysis aimed to systematically examine the relationship between influenza vaccination and dementia risk.

METHODS

We searched PubMed, Embase, Web of Science, ScienceDirect, medRxiv, and bioRxiv for studies investigating dementia risk based on influenza vaccination status, up to September 14, 2022. Relative risks (RRs) and 95% confidence intervals (95% CIs) were pooled in the meta-analysis. Subgroup analyses and sensitivity analyses were conducted as well.

RESULTS

Of the 4,087 articles initially reviewed, 6 cohort studies were included in the final meta-analysis, and all eligible studies were at low risk of bias. There were 2,087,195 participants without dementia at baseline (mean age: 61.8-75.5 years, 57.05% males), and 149,804 (7.18%) cases of dementia occurred during 4.00-13.00 years of follow-up. Pooled analysis of adjusted RRs found that influenza vaccination could reduce dementia risk by 31% (RR = 0.69, 95% CI: 0.57-0.83). Subgroup analyses showed that in the study with a mean age of 75-80 years or 75%-100% males, the association was generally weakened compared with studies with a mean age of 60-75 years or 25%-50% males. The results were stable in the sensitivity analyses, and no publication bias was observed.

CONCLUSION

Influenza vaccination in older adults was markedly associated with a decreased risk of dementia. More mechanistic studies and epidemiological studies are needed to clarify the association between influenza vaccination and decreased dementia risk.

Analysis on the intention and influencing factors of free influenza vaccination among the elderly people aged 70 and above in Hangzhou in 2022

Background

Although influenza vaccination is recommended for people aged 70 and above in Hangzhou, and the vaccine is provided free of charge, the elderly influenza vaccination rate is still low. The purpose of this study was to understand the barriers and motivations of older people in deciding to receive free influenza vaccine through questionnaires.

Methods

The method of stratified random sampling was adopted to take samples. A questionnaire survey was conducted among the elderly aged 70 years and above by face-to-face interview or telephone interview.

Results

A total of 11,663 elderly people aged 70-100 years were successfully and effectively interviewed. 85.98% of the respondent were willing to get the influenza shot, 8.91% were unwilling to get the influenza shot, and 5.11% were on vaccine hesitancy. The people of age of 70-79 years old (hesitancy: OR 70~79 = 0.668, 95%CI: 0.571 0.782, Unwilling: OR 70 - 79 = 0.755, 95%CI: 0.622 0.916), primary school degree or below (hesitancy: OR Secondary school degree or above = 1.467, 95%CI: 1.249 1.724, Unwilling: OR Secondary school degree or above = 1.255, 95%CI: 1.028 1.535), remote areas (hesitancy: OR near central urban area = 2.111, 95%CI: 1.604 2.778, OR central urban area = 2.957, 95%CI: 2.255 3.877, Unwilling: OR near central urban area = 1.687, 95%CI: 1.230 2.313. OR centralurbanarea = 2.218, 95%CI: 1.626 3.027), and convenient for movement (hesitancy: OR yes = 0.494, 95%CI: 0.420 0.580, Unwilling: OR yes = 0.585, 95%CI: 0.480 0.713), understanding of the free vaccine policy (hesitancy: OR understand = 0.204, 95%CI: 0.171 0.245, Unwilling: OR understand = 0.164, 95%CI: 0.128 0.210), influenza knowledge level≥ 13 points (hesitancy: OR ≥13points = 0.628, 95%CI: 0.533 0.739, Unwilling: OR ≥13points = 0.538, 95%CI: 0.437 0.662), influenza vaccine knowledge level≥ 12 points (hesitancy: OR ≥12points = 0.422, 95%CI: 0.350 0.508, Unwilling: OR ≥12points = 0.370, 95%CI: 0.290 0.472), and social trust level ≥ 12 points (hesitancy: OR ≥12points = 0.134, 95%CI: 0.112 0.160, Unwilling: OR ≥12points = 0.220, 95%CI: 0.180 0.269) are more willing to receive free influenza vaccine.

Conclusion

The proportion of elderly people aged 70 and above who are willing to receive free influenza vaccine is high in Hangzhou. But the level of knowledge about influenza, vaccine and trust in society is low. The government should continue to improve the elderly's awareness and trust in society through medical staff, family members, television and radio media, and guide the elderly to actively vaccinate against influenza. Effective publicity should be carried out through the above channels to guide the elderly to actively vaccinate against influenza.

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.

The burden of seasonal influenza in Italy: A systematic review of influenza-related complications, hospitalizations, and mortality

Reliable country‐specific data on influenza burden play a crucial role in informing prevention and control measures. Our purpose was to provide a comprehensive summary of the available evidence on the burden of seasonal influenza in Italy. We performed a systematic literature review of articles published until July 31, 2020. PubMed, Embase, and Web of Science were searched using terms related to burden, influenza, and Italian population. We included studies investigating seasonal influenza‐related complications, hospitalizations, and/or mortality. Sixteen studies were included: eight (50%) analyzed influenza‐related complications, eight (50%) hospitalizations, and seven (43.8%) influenza‐related deaths. Only three studies (19.7%) concerned pediatric age. The synthesis of results showed that patients with chronic conditions have an increased risk for complications up to almost three times as compared with healthy people. Hospitalizations due to influenza can occur in as much as 5% of infected people depending on the study setting. Excess deaths rates were over sixfold higher in the elderly as compared with the rest of population. Although there are still gaps in existing data, there is evidence of the significant burden that influenza places each year especially on high‐risk groups. These data should be used to inform public health decision‐making.

Impact of immunization programs on 11 childhood vaccine-preventable diseases in China: 1950-2018

To evaluate the achievements of China's immunization program between 1950 and 2018, we chose 11 vaccine-preventable diseases (VPDs) as representative notifiable diseases and used annual surveillance data obtained between 1950 and 2018 to derive disease incidence and mortality trends. Quasi-Poisson and polynomial regression models were used to estimate the impacts of specific vaccine programs, and life-table methods were used to calculate the loss of life expectancy, years of life lost, and loss of working years. The total notification number for the 11 VPDs was 211,866,000 from 1950 to 2018. The greatest number occurred in 1959, with a total incidence of 1,723 per million persons. From 1978 to 2018, a substantial decline was observed in the incidence of major infectious diseases. The incidence of pertussis fell 98% from 126.35 to 1.58 per million, and the incidences of measles, meningococcal meningitis, and Japanese encephalitis fell 99%, 99%, and 98%, respectively. The regression models showed that most of the 11 diseases exhibited dramatic declines in morbidity after their integration into the Expanded Program on Immunization (EPI), while varicella and paratyphoid fever, which were not integrated into the EPI, showed increased morbidity. From 1978 to 2018, the total life expectancy for the 11 VPDs increased by 0.79 years, and similar results were obtained for different age groups. China has had great success in controlling VPDs in recent decades, and improving vaccination coverage is a key aspect of controlling VPDs in China.

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11 vaccine-preventable diseases (VPDs) were examined to measure the impact of the national immunization program

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Most of the 11 VPDs exhibited dramatic declines in morbidity rate after their integration into the Expanded Program on Immunization (EPI)

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From 1978 to 2018, the total life expectancy for the 11 VPDs increased by 0.79 years, and similar results were obtained for different age groups

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Improving vaccination coverage is a key aspect of controlling VPDs in China

Pneumococcal and Influenza Vaccination Rates and Pneumococcal Invasive Disease Rates Set Geographical and Ethnic Population Susceptibility to Serious COVID-19 Cases and Deaths

This study examines the relationship of pneumococcal vaccination rates, influenza, measles-mumps-rubella (MMR) diphtheria-tetanus-pertussis vaccinations (DTP), polio, Haemophilus influenzae type B (Hib), and Bacillus Calmette-Guerin (tuberculosis) vaccination rates to COVID-19 case and death rates for 51 nations that have high rates of COVID-19 testing and for which nearly complete childhood, at-risk adult and elderly pneumococcal vaccination data were available. The study is unique in a large number of nations examined, the range of vaccine controls, in testing effects of combinations of vaccinations, and in examining the relationship of COVID-19 and vaccination rates to invasive pneumococcal disease (IPD). Analysis of Italian regions and the states of the United States were also performed. Significant positive correlations were found between IPD (but not lower respiratory infections) and COVID-19 rates, while significant negative correlations were found between pneumococcal vaccination and COVID-19 rates. Influenza and MMR vaccination rates were negatively correlated with lower respiratory infection (LRI) rates and may synergize with pneumococcal vaccination rates to protect against COVID-19. Pneumococcal and influenza vaccination rates were independent of other vaccination rates. These results suggest that endemic rates of bacterial pneumonias, for which pneumococci are a sentinel, may set regional and national susceptibility to severe COVID-19 disease and death.

Impact of Influenza Vaccination on Mortality in the Oldest Old: A Propensity Score-Matched Cohort Study

Influenza remains a major cause of illness and death in geriatric populations. While the influenza vaccine has successfully reduced morbidity and mortality, its effectiveness is suspected to decrease with age. The aim of this study was to assess the impact of influenza vaccination on all-cause mortality in very old ambulatory subjects. We conducted a prospective cohort study from 1 July 2016 to 31 June 2017 in a large unselected ambulatory population aged over 80 years. We compared all-cause mortality in vaccinated versus unvaccinated subjects after propensity-score matching, to control for age, sex and comorbidities. Among the 9149 patients included, with mean age 86 years, 4380 (47.9%) were vaccinated against influenza. In total, 5253 (57.4%) had at least one chronic disease. The most commonly vaccinated patients were those with chronic respiratory failure (76.3%) and the least commonly vaccinated were those suffering from Parkinson’s disease (28.5%). Overall, 2084 patients (22.8%) died during the study. After propensity score matching, the mortality was evaluated at 20.9% in the vaccinated group and 23.9% in the unvaccinated group (OR = 0.84 [0.75–0.93], p = 0.001). This decrease in mortality in the vaccinated group persisted whatever the age and Charlson Comorbidity index. In conclusion, nearly a half of this ambulatory elderly population received Influenza vaccine. After adjustment on comorbidities, influenza vaccination was associated with a significant decrease in all-cause mortality, even in the eldest multimorbid population. Improving immunization coverage in this frail older population is urgently needed.

Effectiveness of influenza vaccine in reducing influenza-associated hospitalizations and deaths among the elderly population; Lazio region, Italy, season 2016-2017

BACKGROUND

This study aimed to estimate influenza vaccine effectiveness (VE) in preventing influenza-related deaths and hospitalizations in the elderly population.

METHODS

We retrospectively analyzed the cohort of 1,251,218 elderly aged ≥65 years who were residing in the Lazio region in 2016-2017. We estimated influenza VE using the Cox proportional hazards model, adjusting for demographic characteristics, preexisting health-risk conditions, and prior vaccinations.

RESULTS

Estimated VE was 14% (95% confidence interval (CI): 11 to 17); 26% (95%CI: 19 to 33) in preventing influenza-related deaths and 13% (95%CI: 10 to 16) in preventing influenza-related hospitalizations. Seasonal VE was higher in the elderly vaccinated in prior seasons (VE = 20%, 95%CI: 17 to 23). We found no significant differences in effectiveness by vaccine type, although the MF59-adjuvanted vaccine appeared more effective than other vaccines in individuals aged ≥75 years, particularly in those aged ≥90 years (VE = 18%, 95%CI: 9 to 26).

CONCLUSIONS

Although VE was low, vaccination still provided benefits in preventing influenza-related hospitalizations and deaths in the elderly, particularly among those vaccinated in prior seasons. Efforts should therefore be made to improve vaccine uptake and the utilization of vaccines with greater effectiveness in the oldest elderly (e.g. high-dose and adjuvanted cell-based vaccines).