Association between vaccination coverage decline and influenza incidence rise among Italian elderly

Time lapses between distribution of influenza vaccines to health authorities and their administration by General Practitioners (GPs) to older adults: a retrospective study over five influenza seasons in Italy

BACKGROUND

Delays in influenza vaccine delivery and administration can hinder vaccine coverage and protection. This study examines the differentials in distributing and administering adjuvanted trivalent (aTIV) and quadrivalent influenza vaccines (aQIV) to older adults in Italy's primary care setting and its potential impact on hospitalization risk over 5 epidemic seasons.

METHODS

Using a primary care database, individuals aged ≥ 65 years were selected. The proportion of vaccine distribution to regional authorities and subsequent administration by GPs was estimated using census data. Using quantile (median) regression, we examined the relationship between velocities of vaccine distribution and administration (doses/week) and the incidence of hospitalizations.

RESULTS

Over the 5 influenza seasons, the velocity of distribution and administration of aTIV/aQIV ranged 341-833 and 152-270 median doses/week; no trend was yielded for the difference between these velocities (p = 0.189) or vaccine coverage (p = 0.142). An association was observed for each differential dose/week between distributed and administered vaccines and all-cause hospitalizations with a 10% increase in 2017-2018, 54% in 2018-2019, and 12% in 2020-2021 season.

CONCLUSIONS

These findings highlight the importance of minimizing the time lapse between vaccine distribution and administration to mitigate the impact of influenza and address factors that contribute to vaccination barriers.

Population-level benefits of increasing influenza vaccination uptake among Italian older adults: results from a granular panel model

Background

The impact of seasonal influenza vaccination (SIV) on mortality is still controversial; some studies have claimed that increasing vaccination coverage rates is beneficial, while others have found no significant association. This study aimed to construct a granular longitudinal dataset of local VCRs and assess their effect on pneumonia- and influenza-related (P&I) mortality among Italian adults aged ≥ 65 years.

Methods

NUTS-3 (nomenclature of territorial units for statistics) level data on SIV coverage were collected via a survey of local data holders. Fixed- and random-effects panel regression modeling, when adjusted for potential confounders, was performed to assess the association between local SIV coverage rates and P&I mortality in older adults.

Results

A total of 1,144 local VCRs from 2003 to 2019 were ascertained. In the fully adjusted fixed-effects model, each 1% increase in vaccination coverage was associated (P < 0.001) with a 0.6% (95% CI: 0.3-0.9%) average over-time decrease in P&I mortality. With an annual average of 9,293 P&I deaths in Italy, this model suggested that 56 deaths could have been avoided each year by increasing SIV coverage by 1%. The random-effects model produced similar results. The base-case results were robust in a sensitivity analysis.

Conclusion

Over the last two decades, Italian jurisdictions with higher SIV uptake had, on average, fewer P&I deaths among older adults. Local policy-makers should implement effective strategies to increase SIV coverage in the Italian senior population.

The Impact of Cold Ambient Temperature in the Pattern of Influenza Virus Infection

Background

Prior literature suggests that cold temperature strongly influences the immune function of animals and human behaviors, which may allow for the transmission of respiratory viral infections. However, information on the impact of cold stimuli, especially the impact of temporal change in the ambient temperature on influenza virus transmission, is limited.

Methods

A susceptible-infected-recovered-susceptible model was applied to evaluate the effect of temperature change on influenza virus transmission.

Results

The mean temperature of the prior week was positively associated with the number of newly diagnosed cases (0.107 [95% Bayesian credible interval {BCI}, .106-.109]), whereas the mean difference in the temperature of the prior week was negatively associated (-0.835 [95% BCI, -.840 to -.830]). The product of the mean temperature and mean difference in the temperature of the previous week were also negatively associated with the number of newly diagnosed cases (-0.192 [95% BCI, -.197 to -.187]).

Conclusions

The mean temperature and the mean difference in temperature affected the number of newly diagnosed influenza cases differently. Our data suggest that high ambient temperature and a drop in the temperature and their interaction increase the risk of infection. Therefore, the highest risk of infection is attributable to a steep fall in temperature in a relatively warm environment.

From Outbreak to Near Disappearance: How Did Non-pharmaceutical Interventions Against COVID-19 Affect the Transmission of Influenza Virus?

Influenza shares the same putative transmission pathway with coronavirus disease 2019 (COVID-19), and causes tremendous morbidity and mortality annually globally. Since the transmission of COVID-19 in China, a series of non-pharmaceutical interventions (NPIs) against to the disease have been implemented to contain its transmission. Based on the surveillance data of influenza, Search Engine Index, and meteorological factors from 2011 to 2021 in Xi'an, and the different level of emergence responses for COVID-19 from 2020 to 2021, Bayesian Structural Time Series model and interrupted time series analysis were applied to quantitatively assess the impact of NPIs in sequent phases with different intensities, and to estimate the reduction of influenza infections. From 2011 to 2021, a total of 197,528 confirmed cases of influenza were reported in Xi'an, and the incidence of influenza continuously increased from 2011 to 2019, especially, in 2019-2020, when the incidence was up to 975.90 per 100,000 persons; however, it showed a sharp reduction of 97.68% in 2020-2021, and of 87.22% in 2021, comparing with 2019-2020. The highest impact on reduction of influenza was observed in the phase of strict implementation of NPIs with an inclusion probability of 0.54. The weekly influenza incidence was reduced by 95.45%, and an approximate reduction of 210,100 (95% CI: 125,100-329,500) influenza infections was found during the post-COVID-19 period. The reduction exhibited significant variations in the geographical, population, and temporal distribution. Our findings demonstrated that NPIs against COVID-19 had a long-term impact on the reduction of influenza transmission.

Nudging toward vaccination: a systematic review

Background

Vaccine hesitancy (VH) and the global decline of vaccine coverage are a major global health threat, and novel approaches for increasing vaccine confidence and uptake are urgently needed. ‘Nudging’, defined as altering the environmental context in which a decision is made or a certain behaviour is enacted, has shown promising results in several health promotion strategies. We present a comprehensive synthesis of evidence regarding the value and impact of nudges to address VH.

Methods

We conducted a systematic review to determine if nudging can mitigate VH and improve vaccine uptake. Our search strategy used Medical Subject Headings (MeSH) and non-MeSH terms to identify articles related to nudging and vaccination in nine research databases. 15 177 titles were extracted and assessed following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The final list of included articles was evaluated using the Mixed Methods Appraisal Tool and the Grading of Recommendations, Assessment, Development and Evaluations framework.

Findings

Identified interventions are presented according to a framework for behaviour change, MINDSPACE. Articles (n=48) from 10 primarily high-income countries were included in the review. Nudging-based interventions identified include using reminders and recall, changing the way information is framed and delivered to an intended audience, changing the messenger delivering information, invoking social norms and emotional affect (eg, through storytelling, dramatic narratives and graphical presentations), and offering incentives or changing defaults. The most promising evidence exists for nudges that offer incentives to parents and healthcare workers, that make information more salient or that use trusted messengers to deliver information. The effectiveness of nudging interventions and the direction of the effect varies substantially by context. Evidence for some approaches is mixed, highlighting a need for further research, including how successful interventions can be adapted across settings.

Conclusion

Nudging-based interventions show potential to increase vaccine confidence and uptake, but further evidence is needed for the development of clear recommendations. The ongoing COVID-19 pandemic increases the urgency of undertaking nudging-focused research.

PROSPERO registration number

CRD42020185817.

Analysis of the vaccination status of older adults

OBJECTIVE

To describe the sociodemographic characteristics, functional capacity and vaccination status of older adults, and to verify the factors associated with the incomplete vaccination status and the absence of the vaccination card.

METHOD

Cross-sectional and analytical study conducted with older adults living in the city of Uberaba (MG). The following analyzes were carried out: descriptive, bivariate and multinomial logistic regression (p<0.05).

RESULTS

A total of 576 older adults participated. Most of them were women, in the 70-80 age group, with partner, low education and income, living with someone, independent in basic activities of daily living and with partial dependence on instrumental activities. The highest percentage was for older adults who had incomplete vaccination status, especially regarding the absence of immunization for Hepatitis B. Individual monthly income < 1 minimum wage (p=0.002) and single-person housing arrangement (p=0.010) were associated with the incomplete vaccination status, and the absence of the vaccination card, with the lowest level of education (p=0.039).

CONCLUSION

Low income and education, as well as living alone, are factors associated with inadequate vaccination status among older adults in the community. The need for primary care nurses to develop strategies to increase vaccination coverage among older adults with these characteristics is emphasized.

Impact of COVID-19 Pandemic on Flu and COVID-19 Vaccination Intentions among University Students

Flu vaccination for the general population, and specifically for vulnerable subgroups, brings the potential to reduce the impact of the COVID-19 pandemic in terms of mobility, mortality, and hospitalizations. In Italy, flu vaccination is recommended to all ≥6 months of age, even if it is only free of charge for specific categories. We investigated the intentions towards flu and COVID-19 vaccinations from a sample of 436 Italian university students. Results of a web-based survey show that 77.52% of them were willing to get the flu vaccine and 94.73% were willing to be vaccinated against COVID-19 when available. We identified positive predictive factors to undertake flu vaccination as being a medical student, having undertaken a previous vaccination against flu, and having a high level of concern and perceived vulnerability to the COVID-19 pandemic. Reinforced public health activities might consider engaging university students a as possible "positive influencer" towards flu and COVID-19 vaccination programs.

Sociocultural, behavioural and political factors shaping the COVID-19 pandemic: the need for a biocultural approach to understanding pandemics and (re)emerging pathogens

Although there has been increasing focus in recent years on interdisciplinary approaches to health and disease, and in particular the dimension of social inequalities in epidemics, infectious diseases have been much less focused on. This is especially true in the area of cultural dynamics and their effects on pathogen behaviours, although there is evidence to suggest that this relationship is central to shaping our interactions with infectious disease agents on a variety of levels. This paper makes a case for a biocultural approach to pandemics such as COVID-19. It then uses this biocultural framework to examine the anthropogenic dynamics that influenced and continue to shape the COVID-19 pandemic, both during its initial phase and during critical intersections of the pandemic. Through this understanding of biocultural interactions between people, animals and pathogens, a broader societal and political dimension is drawn as a function of population level and international cultures, to reflect on the culturally mediated differential burden of the pandemic. Ultimately, it is argued that a biocultural perspective on infectious disease pandemics will allow for critical reflection on how culture shapes our behaviours at all levels, and how the effects of these behaviours are ultimately foundational to pathogen ecology and evolution.

Data-driven contact structures: From homogeneous mixing to multilayer networks

The modeling of the spreading of communicable diseases has experienced significant advances in the last two decades or so. This has been possible due to the proliferation of data and the development of new methods to gather, mine and analyze it. A key role has also been played by the latest advances in new disciplines like network science. Nonetheless, current models still lack a faithful representation of all possible heterogeneities and features that can be extracted from data. Here, we bridge a current gap in the mathematical modeling of infectious diseases and develop a framework that allows to account simultaneously for both the connectivity of individuals and the age-structure of the population. We compare different scenarios, namely, i) the homogeneous mixing setting, ii) one in which only the social mixing is taken into account, iii) a setting that considers the connectivity of individuals alone, and finally, iv) a multilayer representation in which both the social mixing and the number of contacts are included in the model. We analytically show that the thresholds obtained for these four scenarios are different. In addition, we conduct extensive numerical simulations and conclude that heterogeneities in the contact network are important for a proper determination of the epidemic threshold, whereas the age-structure plays a bigger role beyond the onset of the outbreak. Altogether, when it comes to evaluate interventions such as vaccination, both sources of individual heterogeneity are important and should be concurrently considered. Our results also provide an indication of the errors incurred in situations in which one cannot access all needed information in terms of connectivity and age of the population.

Spatiotemporal Analysis of Influenza in China, 2005-2018

Influenza is a major cause of morbidity and mortality worldwide, as well as in China. Knowledge of the spatial and temporal characteristics of influenza is important in evaluating and developing disease control programs. This study aims to describe an accurate spatiotemporal pattern of influenza at the prefecture level and explore the risk factors associated with influenza incidence risk in mainland China from 2005 to 2018. The incidence data of influenza were obtained from the Chinese Notifiable Infectious Disease Reporting System (CNIDRS). The Besag York Mollié (BYM) model was extended to include temporal and space-time interaction terms. The parameters for this extended Bayesian spatiotemporal model were estimated through integrated nested Laplace approximations (INLA) using the package R-INLA in R. A total of 702,226 influenza cases were reported in mainland China in CNIDRS from 2005–2018. The yearly reported incidence rate of influenza increased 15.6 times over the study period, from 3.51 in 2005 to 55.09 in 2008 per 100,000 populations. The temporal term in the spatiotemporal model showed that much of the increase occurred during the last 3 years of the study period. The risk factor analysis showed that the decreased number of influenza vaccines for sale, the new update of the influenza surveillance protocol, the increase in the rate of influenza A (H1N1)pdm09 among all processed specimens from influenza-like illness (ILI) patients, and the increase in the latitude and longitude of geographic location were associated with an increase in the influenza incidence risk. After the adjusting for fixed covariate effects and time random effects, the map of the spatial structured term shows that high-risk areas clustered in the central part of China and the lowest-risk areas in the east and west. Large space-time variations in influenza have been found since 2009. In conclusion, an increasing trend of influenza was observed from 2005 to 2018. The insufficient flu vaccine supplements, the newly emerging influenza A (H1N1)pdm09 and expansion of influenza surveillance efforts might be the major causes of the dramatic changes in outbreak and spatio-temporal epidemic patterns. Clusters of prefectures with high relative risks of influenza were identified in the central part of China. Future research with more risk factors at both national and local levels is necessary to explain the changing spatiotemporal patterns of influenza in China.

Knowledge, attitudes, and practices of influenza and pneumococcal vaccines among agricultural workers: results of an Italian a cross-sectional study

BACKGROUND

Working age is increasing across Europe. Seasonal influenza (SID) and pneumococcal disease (PND) immunization programmes might be successfully implemented at the workplace. We conducted a cross-sectional survey among to assess SID and PND vaccine status, as well as knowledge, attitudes and practices (KAP) in a representative sample of agricultural workers (AWs) aged ≥55 years in North-Eastern Italy.

METHODS

A structured questionnaire was administered in person by trained personnel. Bivariate and multivariate logistic regression analyses were carried out to identify behavioral and work-related factors associated with SID and PND vaccine uptake.

RESULTS

Among 707 participants, 238 were aged 55 years or more (33.7% of total). Of them, 39.1% had an up-to-date immunization status towards influenza, and 17.6% towards pneumococcus. Factors associated with inadequate immunization were doubts about influenza vaccine safety (40.0%) and the confidence in natural immunity towards pneumococcus (30.8%). Attitude towards vaccinations was somehow favorable in 44.5% of participants for SID, and 37.8% for PND. Overall, 37.4% and 21.8% workers were aware of national recommendations on SID and PND immunization, respectively. This factor was characterized as a significant predictor for SID vaccination (multivariated Odds Ratio, OR 32.688 95%CI 12.015-88.930), as well as the perception of SID as a severe disease (OR 7.539 95%CI 3.312-17.164), and the perceived value of preventing new infections (OR 3.215 95%CI 1.205-8.578). A somehow favorable attitude towards vaccinations was the main predictor (OR 39.214 95%CI 10.179-151.1) for PND vaccination.

CONCLUSIONS

Our study indicates that older workers lack appropriate knowledge of national recommendations and correct risk perception of SID and PND infections, but also vaccines' side effects. As the latter has been recognized as predictive factor for SID vaccination, our results stress the importance for tailored informative interventions in the workplaces aimed to increase risk perception and vaccine acceptance. (www.actabiomedica.it).

Effects of temperature, humidity, and diurnal temperature range on influenza incidence in a temperate region

Background

The effect of temperature and humidity on the incidence of influenza may differ by climate region. In addition, the effect of diurnal temperature range on influenza incidence is unclear, according to previous study findings.

Objectives

The aim of this study was to analyze the effects of temperature, humidity, and diurnal temperature range on the incidence of influenza in Seoul, Republic of Korea, which is located in a temperate region.

Methods

We used Korean National Health insurance data to assess the weekly influenza incidence between 2010 and 2016, and used meteorological data from Seoul. To investigate the effect of temperature, relative humidity, and diurnal temperature range levels on influenza incidence, we used a distributed lag non‐linear model.

Results

The risk of influenza incidence was significantly increased with low daily temperatures of 0‐5°C and low (30%–40%) or high (70%) relative humidity. We found a positive significant association between diurnal temperature range and influenza incidence in this study.

Conclusions

Influenza incidence increased with low temperature and low/high humidity in a temperate region. Influenza incidence also increased with high diurnal temperature range, after considering temperature and humidity.

Life Expectancy: Frequently Used, but Hardly Understood

Period life expectancy is one of the most used summary indicators for the overall health of a population. Its levels and trends direct health policies, and researchers try to identify the determining risk factors to assess and forecast future developments. The use of period life expectancy is often based on the assumption that it directly reflects the mortality conditions of a certain year. Accordingly, the explanation for changes in life expectancy are typically sought in factors that have an immediate impact on current mortality conditions. It is frequently overlooked, however, that this indicator can also be affected by at least three kinds of effects, in particular in the situation of short-term fluctuations: cohort effects, heterogeneity effects, and tempo effects. We demonstrate their possible impact with the example of the almost Europe-wide decrease in life expectancy in 2015, which caused a series of reports about an upsurge of a health crisis, and we show that the consideration of these effects can lead to different conclusions. Therefore, we want to raise an awareness concerning the sensitivity of life expectancy to sudden changes and the menaces a misled interpretation of this indicator can cause.

Analysis of influenza vaccination coverage among the elderly living in Rome, based on a deprivation index, 2009-2013

INTRODUCTION

Elderly people are more likely to develop influenza-related complications. However, despite the recommendations, the optimal vaccination coverage is not reached. The use of deprivation indexes can help to identify subgroups with lower vaccination uptake. We analyzed vaccination coverage among elderly subjects living in the city of Rome on the basis of their socioeconomic characteristics by using a local deprivation index.

METHODS

We focused on the population aged ≥ 65 years living in the city of Rome from 2009 to 2013. Information on vaccination coverage was collected from general practitioners. A combination of multivariate techniques, including multiple linear regression, factor and cluster analysis, was used to construct a composite area-based Index of Socio-Economic and Health Deprivation (SEHDI). The index was calculated for each census tract on the basis of data from the 2001 Italian census.

RESULTS

The majority of elderly subjects living in Rome belonged to the medium (40.4%) and medium-high (24%) deprivation groups; only 4.5% of the population was in the low-deprivation group. An inverse relationship was found between influenza vaccination coverage and the deprivation index: elderly subjects in the low-deprivation group displayed lower coverage (55.45%) than those in the high-deprivation group (57.59%). Specifically, vaccination coverage decreased with the increase of replacement index, employment rate and the percentage of: single and divorced individuals; university and high-school graduates; employees, entrepreneurs and freelancers, family assistants, students; foreigners and stateless persons residing in Italy; families consisting of one person.

CONCLUSIONS

Our results show an inverse relationship between deprivation and vaccination coverage and may help to identify subgroups that could benefit from targeted initiatives to increase vaccination coverage.

Analysis of influenza vaccination coverage among the elderly in Genoa (Italy) based on a deprivation index, 2009-2013

Introduction

The elderly suffer the most influenza-related complications, and 90% of deaths due to influenza occur in older subjects. Consequently, the elderly are among the main targets of influenza vaccination campaigns. The use of deprivation indexes can help to identify subgroups with lower vaccination uptake. This study analyzed influenza vaccination coverage in elderly persons living in Genoa (Italy) in relation to a local Index of Socio-Economic and Health Deprivation (SEHDI) in order to identify population subgroups needing specific intervention to improve vaccination coverage.

Methods

The study targeted subjects aged ≥ 65 years living in Genoa in the period 2009-2013. Information on vaccination coverage was provided by general practitioners and Local Health Units. A combination of linear regression, factor analysis and cluster analysis was used to construct the SEHDI at Census Tract (CT) level, on the basis of data from the 2011 Italian census.

Results

In 2011, people aged ≥ 65 years accounted for the 27.7% of the population of Genoa. Most elderly subjects were assigned to either the medium (45.3%) or medium-high (32%) deprivation groups, while the percentages in the extreme tails were low (3.6% high deprivation; 1.3% low deprivation). Significant, non-linear (p < 0.05 NL) relationships were observed in both sexes with regard to mortality due to all respiratory diseases (RD) and chronic obstructive pulmonary disease (COPD), with the highest Standardized Mortality Ratio (SMR) values in women in the high deprivation group of women (1.81, p < 0.05 RD; 1.79, p < 0.05 COPD). The SMRs for influenza and pneumonia showed a positive linear trend in women (p < 0.05) with the highest value in the high deprivation group (1.97, p < 0.05), while in men the trend was NL (p < 0.05). A positive linear trend (p < 0.05) was found with regard to vaccination coverage, which grew weakly as deprivation increased, up to the medium-high deprived group (from 34.6% to 44.4%). However, the high deprivation group showed the lowest value (33.3%).

Conclusions

The results revealed a relationship between deprivation and influenza vaccination coverage in the elderly. This finding should be taken into account in the organization of vaccination campaigns and should prompt differentiated intervention in each local area.

Influenza vaccination coverage and deprivation among the elderly in the municipality of Cagliari: results and perspectives

INTRODUCTION

The elderly are among the main targets of influenza vaccination campaigns. Previous studies have shown that socio-economic status influences compliance with influenza vaccination, particularly in the elderly. Deprivation indexes can therefore be useful in identifying population groups with lower vaccination uptake and guide targeted intervention to improve vaccination coverage. We analysed the correlation between influenza vaccination coverage and levels of socio-economic and health deprivation among the population of Cagliari, by means of an Index of Socio-Economic and Health Deprivation (SEHDI) specifically tailored to the city, in order to identify population subgroups needing specific intervention to improve vaccination coverage.

METHODS

A combination of linear regression, factor analysis and cluster analysis was adopted in order to build the SEHDI at the Census Tract (CT) level; data were taken from the 2011 Italian Census. Mortality among subjects aged ≥ 65 years in Cagliari in the period 2013-2015 was used to select the SEHDI variables. On the basis of the SEHDI, his population was classified into five normalised deprivation groups. Information on vaccination coverage was provided by general practitioners and Local Health Units. Cause-specific mortality and information on vaccination coverage in the deprivation groups were analysed by means of ANOVA (F test at p < 0.05).

RESULTS

Around 20% of the Cagliari population was seen to be living in disadvantaged conditions. The trends in Standard Mortality Rates (SMRs) for all causes and for respiratory diseases, chronic obstructive pulmonary diseases (COPD), influenza and pneumonia were analysed across the deprivation groups. Pneumonia and flu mortality rates displayed a non-linear trend in men and a positive linear trend in women. Flu vaccination uptake rates were low: 27%. Coverage proved to be lower in the two extreme categories and higher in the medium deprivation ones.

CONCLUSIONS

The correlation between low vaccination coverage and socio-economic deprivation not only underlines the important role of vaccination in safeguarding health, but also the fact that it can be considered a factor in ensuring the system's equality, thanks to its role in limiting health impacts on those living in the most problematic or disadvantaged circumstances. It also stresses the characteristics which contribute to low compliance. Therefore, this finding should be taken into account in the organization of vaccination campaigns and should prompt differentiated interventions in each local area.