Influenza vaccination coverage of population and the factors influencing influenza vaccination in mainland China: A meta-analysis

Changes of influenza vaccination rate and associated influencing factors after the COVID-19 pandemic in Shanghai, China

The vaccination rate for seasonal influenza remains low in most regions of China. It is essential to understand the factors that associated with the low influenza vaccination rate in various populations after the COVID-19 pandemic. A cross-sectional survey was conducted with residents in Pudong New Area, Shanghai, China. Respondents' vaccination condition during the 2021-2022 flu season and the reasons for receiving or not receiving influenza vaccine were investigated. Binary logistic regression was conducted to explore potential factors influencing vaccination uptake. 2,476 of 14,001 respondents received an influenza vaccine, with a total coverage of 17.68% (95% CI: 17.05%, 18.32%). Children had the highest vaccination coverage (35.68%; 95% CI: 34.02, 37.33), followed by adults (12.75%; 95% CI: 11.91%, 13.58%) and elderly individuals (11.70%, 95% CI: 10.78%, 12.62%). For children, lower household income was an significant promoting factor. For adults, factors significantly associated with vaccination were household income, sex, and education level. For elderly, factors significantly associated with vaccination were household income, education level, living state, and having underlying diseases. (P < .05)The main reason for vaccine hesitancy among children was worried about side effects (21.49%), for adults and elderly was self-rated good health (adults: 37.14%, elderly people: 30.66%). The overall influenza vaccination coverage rate in Shanghai, especially among elderly individuals, is lower than many developed countries. Appropriate strategies and programs targeting different populations need to be implemented to enhance influenza vaccine coverage.

Effectiveness of influenza vaccine among the population in Chongqing, China, 2018-2022: A test negative design-based evaluation

Influenza vaccination is the most cost-effective strategy for influenza prevention. Influenza vaccines have been found to be effective against symptomatic and medically attended outpatient influenza illnesses. However, there is currently a lack of data regarding the effectiveness of inactivated influenza vaccines in Chongqing, China. We conducted a prospective observational test-negative design study. Outpatient and emergency cases presenting with influenza-like illnesses (ILI) and available influenza reverse transcription polymerase chain reaction (RT-PCR) were selected and classified as cases (positive influenza RT-PCR) or controls (negative influenza RT-PCR). A total of 7,307 cases of influenza and 7,905 control subjects were included in this study. The overall adjusted influenza vaccine effectiveness (IVE) was 44.4% (95% confidence interval (CI): 32.5-54.2%). In the age groups of less than 6 years old, 6-18 years old, and 19-59 years old, the adjusted IVE were 32.2% (95% CI: 10.0-48.9%), 48.2% (95% CI: 30.6-61.4%), and 72.0% (95% CI: 43.6-86.1%). The adjusted IVE for H1N1, H3N2 and B (Victoria) were 71.1% (95% CI: 55.4-81.3%), 36.1% (95% CI: 14.6-52.2%) and 33.7% (95% CI: 14.6-48.5%). Influenza vaccination was effective in Chongqing from 2018 to 2022. Evaluating IVE in this area is feasible and should be conducted annually in the future.

The impact of the COVID-19 pandemic and the free vaccination policy on seasonal influenza vaccination uptake among older adults in Ningbo, Eastern China

In 2020-21, during the COVID-19 pandemic, a free influenza vaccination program was initiated among the elderly residents in Ningbo, China. The impact of the COVID-19 pandemic and free vaccination policy on influenza vaccine uptake needs to be evaluated. The influenza vaccine uptake among individuals born before 31 December, 1962 from 2017-18 to 2022-23 season in Ningbo was analyzed. Multivariate logistic regressions were used to estimate the impact of the COVID-19 pandemic and free vaccination policy. Our analysis included an average of 1,856,565 individuals each year. Influenza vaccination coverage increased from 1.14% in 2017-18 to 33.41% in 2022-23. The vaccination coverage among the free policy target population was 50.03% in 2022-23. Multivariate analysis showed that free vaccination policy increased influenza vaccine uptake most (OR = 11.99, 95%CI: 11.87-12.11). The initial phase of the pandemic was associated with a positive effect on influenza vaccination (OR = 2.09, 95%CI: 2.07-2.12), but followed by a negative effect in the subsequent two seasons(2021-22: OR = 0.75, 95%CI: 0.73-0.76; 2022-23: OR = 0.40, 95%CI: 0.39-0.40). COVID-19 vaccination in the current season was a positive predictor of influenza vaccine uptake while not completing booster COVID-19 vaccination before was negative predictor in 2022-23. Having influenza vaccine history and having ILI medical history during the last season were also positive predictors of influenza vaccine uptake. Free vaccination policies have enhanced influenza vaccination coverage among elderly population. The COVID-19 pandemic plays different roles in different seasons. Our study highlights the need for how to implement free vaccination policies targeting vulnerable groups with low vaccination coverage.

Understanding herpes zoster vaccine hesitancy and information asymmetry: a qualitative study in China

Background

Herpes zoster is more prevalent among the older adult due to the age-related immune decline, leading to significant pain and complications. Although vaccination effectively prevents viral infections, vaccine hesitancy remains a major barrier to achieving high vaccination rates.To address this, we conducted a qualitative survey using Vaccine Hesitancy Determinants Matrix and 5C model to understand and improve vaccination rates in this group.

Methods

Descriptive qualitative research design based on the philosophical underpinnings of naturalistic inquiry and purposive sampling methodology was conducted on adults aged 50 and above, as well as community health workers. Data were collected through semi-structured, in-depth personal interviews. The interview outline was constructed following a comprehensive review of the literature and consideration of the theoretical framework.

Results

Seventeen adults over 50 years and four community healthcare workers were included in this study. The study found that information asymmetry in immunization planning was evident at all stages of vaccine supply, dissemination and demand. The main manifestations included limited access to authoritative information, insufficient community awareness of herpes zoster as a route of vaccination, insufficient vocational training, significant gaps in vaccine knowledge, and high levels of complacency among individual residents.

Conclusion

Herpes zoster vaccine hesitancy is prevalent among middle-aged and older adults in China due to information asymmetry, vaccine complacency, inadequate community services, and other multiple layers of factors. Public health strategies should aim to reduce cognitive biases and information gaps by disseminating diverse and credible vaccine information through social media, medical institutions, and offline channels to promote higher vaccination rates.

Combating the Co-Circulation of SARS-CoV-2 and Seasonal Influenza: Identifying Multi-Dimensional Factors Associated with the Uptake of Seasonal Influenza Vaccine among a Chinese National Sample

INTRODUCTION

The co-circulation of COVID-19 and seasonal influenza highlighted the importance of promoting influenza vaccination. However, the influenza vaccination rate among the Chinese population is low and requires further promotion. This study examined multi-dimensional factors, such as knowledge of seasonal influenza, health perceptions, cues to action, patient-provider relationships, and COVID-19 pandemic-related factors, in relation to the uptake of the seasonal influenza vaccine (SIV) among the Chinese population.

METHODS

A cross-sectional, self-administered online survey using a quota sampling method was conducted among Chinese adults 18 years and older between June and August 2022. Multivariate logistic regression was performed to explore factors associated with the 2021 SIV behavior.

RESULTS

A total of 3161 individuals from different regions of China were included in this study. The multivariate logistic regression demonstrated that perceived severity of influenza, perceived barriers to taking SIV, cues to action, a stable relationship with providers, worry about contracting COVID-19 in immunization settings, non-pharmaceutical interventions (NPIs), and awareness of the influenza vaccine in protecting against COVID-19 were significantly associated with the SIV uptake.

CONCLUSIONS

This study examined multi-dimensional factors that may influence SIV uptake. Health promotion programs should incorporate multi-dimensional factors, including personal and environmental factors, related to SIV promotion during the co-circulation period.

Parental Hesitancy toward Seasonal Influenza Vaccination for Children under the Age of 18 Years and Its Determinants in the Post-Pandemic Era: A Cross-Sectional Survey among 1175 Parents in China

Children's susceptibility to influenza increased after COVID-19 control measures were lifted. This study investigated parental hesitancy toward seasonal influenza vaccination (SIV) for children and its determinants in the post-pandemic era. An online survey of full-time adult factory workers was conducted in Shenzhen, China in December 2023. This analysis was based on 1175 parents who had at least one child under the age of 18 years. Among all parents, 37.1% were hesitant to have their index child receive SIV. Mothers exhibited lower parental hesitancy toward SIV compared to fathers (31.9% versus 41.3%, p < 0.001). After adjusting for significant background characteristics, mothers and fathers who were more satisfied with the SIV health promotion materials, perceived more severe consequences of seasonal influenza for their children, and perceived more benefits, cues to action, and self-efficacy related to their children's SIV were less likely to exhibit hesitancy toward SIV. Higher frequency of exposure to information about the increasing number of patients or severe cases due to seasonal influenza and other upper respiratory infections on social media was associated with lower parental hesitancy toward SIV among fathers but not mothers. There is a strong need to address parental hesitancy toward SIV for children in the post-pandemic era.

Repeated vaccination does not appear to significantly weaken the protective effect of influenza vaccine in the elderly: A test-negative case-control study in China

BACKGROUND

The impact of repeated influenza vaccination on vaccine effectiveness has been a topic of debate. Conducting more multinational, multicenter studies in different influenza seasons is crucial for a better understanding of this issue. There is a lack of comprehensive related research reports in China.

METHODS

Using the Regional Health Information Platform, we conducted a test-negative case-control study to evaluate the impact of repeated vaccination on the prevention of laboratory-confirmed influenza in individuals aged 60 and above in Ningbo during four influenza seasons from 2018-19 to 2021-22. Influenza-positive cases and negative controls were matched in a 1:1 ratio based on the visiting hospital and the date of influenza testing. Propensity score adjustment and multivariable logistic regression were used to estimate risk and address confounding effects.

RESULTS

During the study period, a total of 30,630 elderly patients underwent influenza virus nucleic acid or antigen testing. After exclusions, we included 1976 cases of influenza-positive and 1976 cases of influenza-negative controls. Multivariable logistic regression analysis revealed that individuals receiving the vaccine in two consecutive seasons did not exhibit a significantly increased risk of influenza illness compared to those receiving the vaccine only in the current season (adjusted odds ratio: 1.22, 95% confidence interval: 0.94-1.58). However, the risk of influenza illness was found to be elevated in individuals who received the vaccine only in the previous season (adjusted odds ratio: 1.56, 95% confidence interval: 1.15-2.10) and even further elevated in those who had not received the vaccine in either of the consecutive two seasons (adjusted odds ratio: 3.39, 95% confidence interval: 2.80-4.09).

CONCLUSIONS

Regardless of the vaccination history in the previous season, receiving the current season influenza vaccine is the best choice for the elderly population. Our study supports the initiative to vaccinate elderly individuals against influenza annually.

Influenza vaccination for heart failure patients: a cost-effectiveness analysis from the perspective of Chinese healthcare system

Purpose

Influenza infection induces cardiovascular events in heart failure (HF) patients, with potential risk reduction through vaccination. This study aims to evaluate the cost-effectiveness of influenza vaccination for HF patients in China.

Methods

We developed a Markov model with a 3-month cycle to simulate the cost-effectiveness of administering the influenza vaccine to patients with HF over a 3-year period. Patients in the model received either the influenza vaccine or a placebo, in addition to standard HF treatment. Cost data, sourced from the China Healthcare Statistic Yearbook and other public records, and effectiveness data from the IVVE (Influenza Vaccine to Prevent Adverse Vascular Events in HF) trial, were incorporated. Specifically, the cost of the influenza vaccine was 75 Chinese Yuan (CNY) (11 USD), the cost of hospitalization for heart failure (HHF) was 9,326 CNY (1,386 USD), and the cost of treatment for pneumonia was 5,984 CNY (889 USD). The study's primary outcome, the incremental cost-effectiveness ratio (ICER), quantifies the incremental cost (CNY and USD) per incremental quality-adjusted life year (QALY). Additional outcomes included total cost, total effectiveness, incremental cost, and incremental effectiveness. We conducted one-way and probabilistic sensitivity analyses (PSA) to assess certainty and uncertainty, respectively. Scenario analysis, considering various situations, was performed to evaluate the robustness of the results.

Results

In the base case analysis, influenza vaccine, compared to placebo, among Chinese HF patients, resulted in a cost increase from 21,004 CNY (3,121 USD) to 21,062 CNY (3,130 USD) and in QALYs from 1.89 to 1.92 (2.55 life years vs. 2.57 life years) per patient. The resulting ICER was 2,331 CNY (346 USD) per QALY [2,080 CNY (309 USD) per life year], falling below the willingness-to-pay threshold based on per capita GDP. One-way sensitivity analysis revealed that disparities in HHF and cardiovascular death rates between groups had the most significant impact on the ICER, while the cost of vaccines had a marginal impact. PSA and scenario analysis collectively affirmed the robustness of our findings.

Conclusion

This study suggests that adding the influenza vaccine to standard treatment regimens for Chinese patients with HF may represent a highly cost-effective option. Further real-world data studies are essential to validate these findings.

Evaluation of the Effect of Influenza Vaccine on the Development of Symptoms in SARS-CoV-2 Infection and Outcome in Patients Hospitalized due to COVID-19

BACKGROUND

COVID-19 is an infectious disease caused by SARS-CoV-2. It is unclear whether influenza vaccination reduces the severity of disease symptoms. Previous studies have suggested a beneficial effect of influenza vaccination on the severity of COVID-19. The aim of this study was to evaluate the possible protective effect of the influenza vaccine on the occurrence of SARS-CoV-2 infection symptoms and prognosis in patients hospitalized with COVID-19.

METHODS

This was a retrospective cohort study of patients who tested positive for SARS-CoV-2, identified by quantitative real-time polymerase chain reaction. Chi-square tests, Kaplan-Meier analysis, and multivariate analysis were performed to assess the association between influenza vaccination and the presence of symptoms in hospitalized patients with COVID-19 and their outcome.

RESULTS

In this study, 1712 patients received positive laboratory tests for SARS-CoV-2; influenza vaccination was a protective factor against the presence of characteristic COVID-19 symptoms such as polypnea, anosmia, dysgeusia, and fever (p < 0.001). Influenza-vaccinated patients had fewer days of hospitalization (p = 0.029).

CONCLUSIONS

The findings of this study support that influenza vaccination is associated with a decrease in the number of symptoms in patients hospitalized due to COVID-19, with fewer days of hospitalization, but not with the outcome of disease.

Parental knowledge, attitudes, and practices toward vaccinating their children against influenza: a cross-sectional study from China

Aims

Influenza infection is a health burden in children, and the influenza vaccine is an important prevention strategy for flu illness. Parents play a crucial role in children's influenza vaccination. The study aimed to assess parental knowledge, attitudes, and practices (KAP) related to influenza illness for their children and explore factors that may impact their decisions.

Methods

This cross-sectional study was conducted in a tertiary hospital in Guangzhou from November 2022 to April 2023. Answers to KAP questions regarding influenza illness and vaccination were summed, with a total KAP score of 20. Univariate and multivariate logistic regression models and linear regression models were conducted to explore the factors associated with influenza vaccination. The results were presented as odds ratios (ORs), β, and 95% confidence intervals (CIs).

Results

Overall, 530 parents were respondents, of whom 162 (30.56%) had vaccinated their children during the past year. The mean KAP score (standard deviation) was 13.40 (3.57). Compared to parents who reported non-vaccinated for their children in the past year, the parents who reported an influenza vaccination have higher knowledge scores, attitude scores, practice scores, and total scores. Child body mass index, parental education level (under college), parental work (part-time), and more than two family members over 60 years old were negatively correlated with knowledge score. Child health condition and knowledge score were positively correlated with attitude score. Parental age was negatively associated with attitude score.

Conclusion

Though high awareness about influenza illness and vaccination for parents, the coverage rate of influenza vaccination in children was lower in Guangzhou. Implementing public health policies is necessary to spread knowledge about influenza illness and vaccination and to promote the practice of receiving the influenza vaccine in children. Education campaigns would help change the attitudes of parents toward vaccinating their children against the flu.

A Prediction Model for Identifying Seasonal Influenza Vaccination Uptake Among Children in Wuxi, China: Prospective Observational Study

BACKGROUND

Predicting vaccination behaviors accurately could provide insights for health care professionals to develop targeted interventions.

OBJECTIVE

The aim of this study was to develop predictive models for influenza vaccination behavior among children in China.

METHODS

We obtained data from a prospective observational study in Wuxi, eastern China. The predicted outcome was individual-level vaccine uptake and covariates included sociodemographics of the child and parent, parental vaccine hesitancy, perceptions of convenience to the clinic, satisfaction with clinic services, and willingness to vaccinate. Bayesian networks, logistic regression, least absolute shrinkage and selection operator (LASSO) regression, support vector machine (SVM), naive Bayes (NB), random forest (RF), and decision tree classifiers were used to construct prediction models. Various performance metrics, including area under the receiver operating characteristic curve (AUC), were used to evaluate the predictive performance of the different models. Receiver operating characteristic curves and calibration plots were used to assess model performance.

RESULTS

A total of 2383 participants were included in the study; 83.2% of these children (n=1982) were <5 years old and 6.6% (n=158) had previously received an influenza vaccine. More than half (1356/2383, 56.9%) the parents indicated a willingness to vaccinate their child against influenza. Among the 2383 children, 26.3% (n=627) received influenza vaccination during the 2020-2021 season. Within the training set, the RF model showed the best performance across all metrics. In the validation set, the logistic regression model and NB model had the highest AUC values; the SVM model had the highest precision; the NB model had the highest recall; and the logistic regression model had the highest accuracy, F1 score, and Cohen κ value. The LASSO and logistic regression models were well-calibrated.

CONCLUSIONS

The developed prediction model can be used to quantify the uptake of seasonal influenza vaccination for children in China. The stepwise logistic regression model may be better suited for prediction purposes.

Enhancing vaccination uptake through community engagement: evidence from China

With growing recognition of the importance of community engagement in addressing public health challenges, its role in promoting healthy behaviors and preventing infectious diseases has gained attention. However, vaccination coverage remains a significant concern in many developing countries. While previous studies have linked community engagement to positive health outcomes, there is a gap in understanding its influence on individual vaccination choices, particularly in the context of developing countries. Utilizing data from the 2021 Chinese General Social Survey (CGSS), this study examines the impact of community engagement on COVID-19 and flu vaccination uptake among 7281 individuals. Community engagement, measured by community vaccination notifications, serves as the key independent variable. The study employs Ordinary Least Squares (OLS) regression and Propensity Score Matching (PSM) methods to analyze the relationship between community engagement and vaccination behavior. The analysis reveals a positive association between community engagement and vaccination rates. Specifically, individuals receiving notifications were more likely to get the COVID-19 vaccine compared to non-recipients (vaccination rates: 100% vs. 53.3%), and flu vaccination rates were also significantly higher among those notified (2.7% vs. 1.9%). Mechanism analysis suggests that individuals receiving community notifications are more aware of the benefits of vaccination, leading to higher vaccination rates among this group. This study underscores the effectiveness of community engagement strategies in promoting positive vaccination behavior among individuals in China. By enhancing awareness and trust in immunization, community engagement initiatives play a crucial role in shaping health behaviors and improving vaccination uptake. These findings emphasize the importance of integrating community engagement approaches into public health interventions to address vaccination challenges.

The multi-dimensional impact of different sources of information on influenza vaccination of college students in China

Objective: To explore whether/how the willingness of Chinese college students to receive the influenza vaccines in the sample is affected by different information channels. Participants: Two hundred and four volunteers were recruited to participate in an anonymous online survey. All participants were college students, mainly undergraduates (81.86%), with a higher proportion of women (56.86%). Methods: Participants answered anonymous questionnaires through the website, including demographic data (age, gender, education, etc.), media exposure channels and frequency, views and attitudes toward influenza vaccines, etc. An ordered logistic regression analysis was conducted to explore the effects of different information sources on influenza vaccination among college students. Results: Exposure to traditional media, digital media, and interpersonal communication promotes college students' understanding of influenza vaccines. Exposure to digital media alleviates college students' hesitation to vaccinate, while interpersonal interaction and digital media exposure promote college students' willingness to vaccinate. Conclusions: Digital media is increasingly important in the lives of Chinese college students to promote healthy behaviors such as influenza vaccinations.

Impact of health education on promoting influenza vaccination health literacy in primary school students: a cluster randomised controlled trial protocol

INTRODUCTION

Influenza is a major public health threat, and vaccination is the most effective prevention method. However, vaccination coverage remains suboptimal. Low health literacy regarding influenza vaccination may contribute to vaccine hesitancy. This study aims to evaluate the effect of health education interventions on influenza vaccination rates and health literacy.

METHODS AND ANALYSIS

This cluster randomised controlled trial will enrol 3036 students in grades 4-5 from 20 primary schools in Dongguan City, China. Schools will be randomised to an intervention group receiving influenza vaccination health education or a control group receiving routine health education. The primary outcome is the influenza vaccination rate. Secondary outcomes include health literacy levels, influenza diagnosis rate, influenza-like illness incidence and vaccine protection rate. Data will be collected through questionnaires, influenza surveillance and self-reports at baseline and study conclusion.

ETHICS AND DISSEMINATION

Ethical approval has been sought from the Ethics Committee of the School of Public Health, Sun Yat-sen University. Findings from the study will be made accessible to both peer-reviewed journals and key stakeholders.

TRIAL REGISTRATION NUMBER

NCT06048406.

Reconstructed influenza A/H3N2 infection histories reveal variation in incidence and antibody dynamics over the life course

Humans experience many influenza infections over their lives, resulting in complex and varied immunological histories. Although experimental and quantitative analyses have improved our understanding of the immunological processes defining an individual's antibody repertoire, how these within-host processes are linked to population-level influenza epidemiology remains unclear. Here, we used a multi-level mathematical model to jointly infer antibody dynamics and individual-level lifetime influenza A/H3N2 infection histories for 1,130 individuals in Guangzhou, China, using 67,683 haemagglutination inhibition (HI) assay measurements against 20 A/H3N2 strains from repeat serum samples collected between 2009 and 2015. These estimated infection histories allowed us to reconstruct historical seasonal influenza patterns and to investigate how influenza incidence varies over time, space and age in this population. We estimated median annual influenza infection rates to be approximately 18% from 1968 to 2015, but with substantial variation between years. 88% of individuals were estimated to have been infected at least once during the study period (2009-2015), and 20% were estimated to have three or more infections in that time. We inferred decreasing infection rates with increasing age, and found that annual attack rates were highly correlated across all locations, regardless of their distance, suggesting that age has a stronger impact than fine-scale spatial effects in determining an individual's antibody profile. Finally, we reconstructed each individual's expected antibody profile over their lifetime and inferred an age-stratified relationship between probability of infection and HI titre. Our analyses show how multi-strain serological panels provide rich information on long term, epidemiological trends, within-host processes and immunity when analyzed using appropriate inference methods, and adds to our understanding of the life course epidemiology of influenza A/H3N2.

The relationship between autophagy and respiratory viruses

Respiratory viruses have caused severe global health problems and posed essential challenges to the medical community. In recent years, the role of autophagy as a critical process in cells in viral respiratory diseases has been noticed. One of the vital catabolic biological processes in the body is autophagy. Autophagy contributes to energy recovery by targeting and selectively directing foreign microorganisms, organelles, and senescent intracellular proteins to the lysosome for degradation and phagocytosis. Activation or suppression of autophagy is often initiated when foreign pathogenic organisms such as viruses infect cells. Because of its antiviral properties, several viruses may escape or resist this process by encoding viral proteins. Viruses can also use autophagy to enhance their replication or prolong the persistence of latent infections. Here, we provide an overview of autophagy and respiratory viruses such as coronavirus, rhinovirus, parainfluenza, influenza, adenovirus, and respiratory syncytial virus, and examine the interactions between them and the role of autophagy in the virus-host interaction process and the resulting virus replication strategy.

Vaccine confidence mediates the association between a pro-social pay-it-forward intervention and improved influenza vaccine uptake in China: A mediation analysis

INTRODUCTION

A Chinese clinical trial has demonstrated that a prosocial pay-it-forward intervention that offered subsidized vaccination and postcard messages effectively increased influenza vaccine uptake and vaccine confidence. This secondary analysis explored the potential mediating role of vaccine confidence on the association between a pay-it-forward intervention and influenza vaccine uptake, and how this might vary by individual annual income levels.

METHODS

Data from 300 participants (150 standard-of-care and 150 pay-it-forward participants) were included in the analysis. We conducted descriptive analysis of demographic and vaccine confidence variables. Multivariable regression and mediation analysis on interventions, vaccine confidence and vaccine uptake were conducted. A sub-group analysis was conducted to further understand whether associations between these variables vary by income levels (<=$1860 or >$1860).

RESULTS

The pay-it-forward intervention was significantly associated with greater levels of perceived influenza vaccine importance (adjusted odds ratio (aOR) = 3.60, 95 %CI: 1.77-7.32), effectiveness (aOR = 3.37, 95 %CI: 1.75-6.52) and safety (aOR = 2.20, 95 %CI: 1.17-4.15). Greater perceived influenza vaccine importance was associated with increased vaccine uptake (aOR = 8.51, 95 %CI: 3.04-23.86). The indirect effect of the pay-it-forward intervention on vaccination was significant through improved perceived influenza vaccine importance (indirect effect1 = 0.07, 95 %CI: 0.02-0.11). This study further revealed that, irrespective of the individual income level, the pay-it-forward intervention was associated with increased vaccine uptake when compared to the standard-of-care approach.

CONCLUSIONS

Pay-it-forward intervention may be a promising strategy to improve influenza vaccine uptake. Perceived confidence in vaccine importance appears to be a potential mediator of the association between pay-it-forward and vaccine uptake.

Risk factors for hospitalization and pneumonia development of pediatric patients with seasonal influenza during February-April 2023

Objectives

In China influenza remains a low activity for continuous 3 years due to COVID-19 controls. We here sought to study the clinical characteristics and risk factors of the influenza infection among children after the mandatory COVID-19 restrictions were lifted.

Methods

We included 1,006 pediatric patients with influenza A virus (IAV) infection, enrolled in one tertiary hospital in Zhenjiang, Jiangsu Province, China, during February to April 2023. Patients were divided into the outpatient (n = 798) and inpatient (n = 208) groups, and their baseline characteristics were compared between two groups to conclude the risk factors for pediatric hospitalization. Separately, pediatric inpatients (n = 208) were further divided into the pneumonia and non-pneumonia groups with comparison of their clinical characteristics, including their laboratory test results and representative radiological features, to derive the key determinants for pneumonia development after hospitalization.

Results

Compared to outpatients, IAV-infected pediatric inpatients exhibited younger age, higher female: male ratio, more co-infection of influenza B virus (IBV) and hematological abnormality. Multivariate regression analysis determined the independent risk factors of hospitalization to be the clinical symptom of abdominal pain (OR = 2.63, [95% CI, 1.05-6.57], p = 0.039), co-infection of IBV (OR = 44.33, [95% CI, 25.10-78.30], p = 0.001), elevated levels of lymphocytes (OR = 2.24, [95% CI,1.65-3.05], p = 0.001) and c-reactive proteins (CRPs) (OR = 1.06, [95% CI, 1.03-1.08], p = 0.001) upon hospital admission. Furthermore, the cough symptom (OR = 17.39, [95% CI, 3.51-86.13], p = 0.001) and hospitalization length (OR = 1.36, [95% CI, 1.12-1.67], p = 0.002) were determined to be risk factors of pneumonia acquirement for pediatric inpatients.

Conclusion

While the abdominal pain, viral co-infection and some hematological abnormality mainly contribute to hospitalization of pediatric patients with IAV infection, the length of hospital stay and clinical sign of coughing upon hospital admission constitute the key determinants for nosocomial pneumonia development.

The association between influenza vaccination and the perception of COVID-19 as well as COVID-19 vaccination behavior among community residents in Anhui province, China

Influenza is a significant public health threat associated with high morbidity and mortality globally. This study investigated the influenza vaccination rate (IVR) among community residents in Anhui province, China, and explored the association between participants' influenza vaccination and their key sociodemographic characteristics, perception of COVID-19 as well as COVID-19 vaccination behavior. We found that the IVR among respondents in Anhui province was 27.85% in 2020. Regression analyses revealed that males (OR = 1.41, 95% CI: 1.01 ~ 1.96), residents with above middle school education (OR = 1.88, 95% CI: 1.04 ~ 3.39), considered themselves likely to be infected with COVID-19 (OR = 1.53, 95% CI: 1.04 ~ 2.24), had received the COVID-19 vaccine (OR = 9.85, 95% CI: 3.49 ~ 27.78), did not plan to receive COVID-19 vaccine in the future (OR = 1.70, 95% CI: 1.17 ~ 2.47), and had no adverse reactions after COVID-19 vaccination (OR = 1.54, 95% CI: 1.04 ~ 2.27) were associated with a higher IVR. The acceptance of influenza vaccination was mainly associated with respondents' gender, education, perception of COVID-19, history of COVID-19 vaccination in city and countryside community residents in Anhui province.

Comparing factors influencing seasonal influenza vaccine acceptance and intentions among Chinese university students residing in China and UK: A cross-sectional study

University students, who face an elevated risk of influenza due to close living quarters and frequent social interactions, often exhibit low vaccine uptake rates. This issue is particularly pronounced among Chinese students, who encounter unique barriers related to awareness and access, emphasizing the need for heightened attention to this problem within this demographic. This cross-sectional study conducted in May-June 2022 involved 1,006 participants (404 in the UK, 602 in Mainland China) and aimed to explore and compare the factors influencing influenza vaccine acceptance and intentions between Chinese university students residing in the UK (C-UK) and Mainland China (C-M). The study employed a self-administered questionnaire based on the Theoretical Domains Framework and Capability Opportunity Motivation-Behavior model. Results revealed that approximately 46.8% of C-UK students received the influenza vaccine in the past year, compared to 32.9% of C-M students. More than half in both groups (C-UK: 54.5%, C-M: 58.1%) had no plans for vaccination in the upcoming year. Knowledge, belief about consequences, and reinforcement significantly influenced previous vaccine acceptance and intention in both student groups. Barriers to vaccination behavior included insufficient knowledge about the influenza vaccine and its accessibility and the distance to the vaccine center. Enablers included the vaccination behavior of individuals within their social circles, motivation to protect others, and concerns regarding difficulties in accessing medical resources during the COVID-19 pandemic. The findings of this study offer valuable insights for evidence-based intervention design, providing evidence for healthcare professionals, policymakers, and educators working to enhance vaccination rates within this specific demographic.

Socioeconomic inequalities in vaccine uptake: A global umbrella review

This global umbrella review aimed to synthesise evidence of socioeconomic inequalities in the uptake of routine vaccinations and identify the mechanisms that may contribute to the association. To our knowledge, no attempt has been made to synthesise the global body of systematic reviews across a variety of vaccines, geographical locations, and measures of SES. The inclusion criteria were as follows: studies assessing vaccination uptake according to education, income, occupation/employment, and/or area-level deprivation; any country or universally recommended routine vaccination (according to the WHO); qualitative or quantitative reviews, published 2011-present. The searches were performed in eight databases. The screening process followed PRISMA-E guidelines, each stage was performed by one reviewer, and a 10% sample checked by a second for consistency. Included reviews underwent data extraction, quality appraisal (AMSTAR-2), and narrative synthesis according to country-context. After deduplication, 9,163 reports underwent title and abstract screening, leaving 119 full texts to be assessed for eligibility. Overall, 26 studies were included in the umbrella review. Evidence for lower uptake amongst disadvantaged SES individuals was found in all 26 reviews. However, 17 reviews showed mixed results, as inverse associations were also identified (lower uptake for advantaged SES, and/or higher uptake for disadvantaged SES). Those that explored high-income countries had a greater prevalence of mixed findings than those focusing on low/middle-income countries. The two most frequently cited mechanisms were vaccination knowledge, and confidence in vaccination or vaccination providers. These mechanisms were often understood by review authors as varying by level of education. We find socioeconomic differences in routine vaccination uptake, but the association did not always follow a gradient. Whilst education may be associated with uptake globally, our study indicates that its role varies by country-context. A limitation is the overlap of some primary studies across the included systematic reviews.

Short-Term Exposure to Ambient Air Pollution and Influenza: A Multicity Study in China

BACKGROUND

Air pollution is a major risk factor for planetary health and has long been suspected of predisposing humans to respiratory diseases induced by pathogens like influenza viruses. However, epidemiological evidence remains elusive due to lack of longitudinal data from large cohorts.

OBJECTIVE

Our aim is to quantify the short-term association of influenza incidence with exposure to ambient air pollutants in Chinese cities.

METHODS

Based on air pollutant data and influenza surveillance data from 82 cities in China over a period of 5 years, we applied a two-stage time series analysis to assess the association of daily incidence of reported influenza cases with six common air pollutants [particulate matter with aerodynamic diameter ≤ 2.5 μ m (PM 2.5 ), particulate matter with aerodynamic diameter ≤ 10 μ m (PM 10 ), NO 2 , SO 2 , CO, and O 3 ], while adjusting for potential confounders including temperature, relative humidity, seasonality, and holiday effects. We built a distributed lag Poisson model for one or multiple pollutants in each individual city in the first stage and conducted a meta-analysis to pool city-specific estimates in the second stage.

RESULTS

A total of 3,735,934 influenza cases were reported in 82 cities from 2015 to 2019, accounting for 72.71% of the overall case number reported in the mainland of China. The time series models for each pollutant alone showed that the daily incidence of reported influenza cases was positively associated with almost all air pollutants except for ozone. The most prominent short-term associations were found for SO 2 and NO 2 with cumulative risk ratios of 1.094 [95% confidence interval (CI): 1.054, 1.136] and 1.093 (95% CI: 1.067, 1.119), respectively, for each 10   μ g / m 3 increase in the concentration at each of the lags of 1-7 d. Only NO 2 showed a significant association with the daily incidence of influenza cases in the multipollutant model that adjusts all six air pollutants together. The impact of air pollutants on influenza was generally found to be greater in children, in subtropical cities, and during cold months.

DISCUSSION

Increased exposure to ambient air pollutants, particularly NO 2 , is associated with a higher risk of influenza-associated illness. Policies on reducing air pollution levels may help alleviate the disease burden due to influenza infection. https://doi.org/10.1289/EHP12146.

Global burden of influenza lower respiratory tract infections in older people from 1990 to 2019

BACKGROUND

Infections with influenza viruses cause severe illness, substantial number of hospitalization and death, especially in older adults. However, few studies have focused on the burden of influenza lower respiratory tract infections (LRTIs) solely in older adults, particularly in low-resource settings.

AIMS

We aimed to estimate the mortality and DALYs of influenza LRTIs for people aged 55 years and older in 204 countries and territories from 1990 to 2019.

METHODS

The Global Burden of Disease (GBD) 2019 study was used to obtain data on mortality and DALYs of influenza LRTIs at the global, regional, and country levels.

RESULTS

In 2019, the global rates for mortality and DALYs of influenza LRTIs were 6.46 per 100,000 [95% uncertainty interval (UI): 2.37-12.62] and 97.39 per 100,000 (95% UI: 34.70-187.03). Although the rates for mortality and DALYs in people aged 55 years and older decreased from 1990 to 2019, the absolute numbers for both increased by 85.84% and 66.56%, respectively. Both the absolute numbers and rates of deaths and DALYs of influenza LRTIs were higher in male than in female in all age groups. Although low-socio-demographic index (SDI) regions experienced the largest declines for the rates of mortality and DALYs of influenza LRTIs over the past three decades, they still had the highest rates for mortality and DALYs in all age groups. Moreover, the absolute numbers and rates of deaths and DALYs of influenza LRTIs showed an increasing trend with age, reaching the peak in the people over 85 years old.

DISCUSSION

Burden of influenza LRTIs in older adults is still high and could continue to grow along with global aging.

CONCLUSION

Efforts to improve vaccination for influenza are needed for preparedness of another influenza pandemic, especially in low-SDI regions.

Cost-effectiveness of seasonal influenza vaccination of children in China: a modeling analysis

BACKGROUND

China has a high burden of influenza-associated illness among children. We aimed to evaluate the cost-effectiveness of introducing government-funded influenza vaccination to children in China (fully-funded policy) compared with the status quo (self-paid policy).

METHODS

A decision tree model was developed to calculate the economic and health outcomes, from a societal perspective, using national- and provincial-level data. The incremental cost-effectiveness ratio (ICER) [incremental costs per quality-adjusted life year (QALY) gained] was used to compare the fully-funded policy with the self-paid policy under the willingness-to-pay threshold equivalent to national and provincial GDP per capita. Sensitivity analyses were performed and various scenarios were explored based on real-world conditions, including incorporating indirect effect into the analysis.

RESULTS

Compared to the self-paid policy, implementation of a fully-funded policy could prevent 1,444,768 [95% uncertainty range (UR): 1,203,446-1,719,761] symptomatic cases, 92,110 (95% UR: 66,953-122,226) influenza-related hospitalizations, and 6494 (95% UR: 4590-8962) influenza-related death per season. The fully-funded policy was cost-effective nationally (7964 USD per QALY gained) and provincially for 13 of 31 provincial-level administrative divisions (PLADs). The probability of a funded vaccination policy being cost-effective was 56.5% nationally, and the probability in 9 of 31 PLADs was above 75%. The result was most sensitive to the symptomatic influenza rate among children under 5 years [ICER ranging from - 25,612 (cost-saving) to 14,532 USD per QALY gained]. The ICER of the fully-funded policy was substantially lower (becoming cost-saving) if the indirect effects of vaccination were considered.

CONCLUSIONS

Introducing a government-funded influenza policy for children is cost-effective in China nationally and in many PLADs. PLADs with high symptomatic influenza rate and influenza-associated mortality would benefit the most from a government-funded influenza vaccination program.

Pay-it-forward influenza vaccination among older adults and children: A cost-effectiveness analysis in China

A quasi-experimental study was conducted to evaluate the effectiveness of a pay-it-forward strategy for increasing influenza vaccination among children and older adults compared to a self-paid vaccination strategy in China. Pay-it-forward is an innovative community-engaged intervention in which participants receive a free influenza vaccination and are then asked if they would like to donate or create a message to support subsequent vaccinations. This economic evaluation used a decision-tree model to compare pay-it-forward to a standard of care arm in which patients had to pay for their own influenza vaccine. The analysis was performed from the healthcare provider perspective and costs were calculated with 2020 United States dollars. The time horizon was one year. In the base case analysis, pay-it-forward was more effective (111 vs 55 people vaccinated) but more costly than standard-of-care ($4477 vs $2725). Pay-it-forward spurred 96.4% (107/111) of individuals to voluntarily donate to support influenza vaccination for high-risk groups in China. Further costing and implementation research is needed to inform scale up.

Coverage and impact of influenza vaccination among children in Minhang District, China, 2013-2020

Background

Young children have a great disease burden and are particularly vulnerable to influenza. This study aimed to assess the direct effect of influenza vaccination among children and to evaluate the indirect benefit of immunizing children.

Methods

The influenza vaccination records for all children born during 2013-2019 in Minhang District and surveillance data for reported influenza cases were obtained from the Minhang CDC. 17,905 children were recorded in the vaccination system and included in this study. Descriptive epidemiology methods were used for data analysis, including an ecological approach to estimate the number of influenza cases averted by vaccination and linear regression to estimate the reduction in influenza cases in the general population per thousand additional childhood vaccination doses.

Results

During the study period, the annual vaccination coverage rate ranged from 10.40% in 2013-2014 to 27.62% in 2015-2016. The estimated number of influenza cases averted by vaccination ranged from a low of 0.28 (range: 0.23-0.34) during 2013-2014 (PF: 6.15%, range: 5.11-7.38%) to a high of 15.34 (range: 12.38-18.51) during 2017-2018 (PF: 16.54%, range: 13.79-19.30%). When increasing vaccination coverage rate by 10% in each town/street, a ratio of 7.27-10.69% cases could be further averted on the basis of observed cases. In four selected periods, the number of influenza cases in the general population was most significantly correlated with the cumulative childhood vaccination doses in the prior 2-5 months, and the reduction in influenza cases ranged from 0.73 to 3.18 cases per thousand additional childhood vaccination doses.

Conclusion

Influenza vaccination among children is estimated to have direct effects in terms of averted cases and might provide an underlying indirect benefit to the general population. Vaccination coverage in high-coverage areas should be further expanded to avert more influenza cases.

Trust, Interaction with Neighbors, and Vaccination during the COVID-19 Pandemic: A Cross-Sectional Analysis of Chinese Data

The COVID-19 pandemic significantly impacted public health and quality of life, leading to government recommendations for vaccination. Using cross-sectional data from a nationwide population-based survey conducted in China (N = 6860), this study aimed to examine the associations between individual vaccine uptake and general trust in others, trust in government, and interaction with neighbors. We conducted a multilevel logistic regression analysis to examine the relevance of these factors at the individual and community levels. Among young adults, higher levels of general trust at both levels were positively associated with vaccination, with odds ratios (OR) of 1.35 (95% confidence interval [CI]: 1.07, 1.70) and 1.58 (95% CI: 1.14, 2.18), respectively. We also found a positive association between vaccination and community-level interaction with neighbors, with ORs of 1.55 (95% CI: 1.11, 2.17). In contrast, among older individuals, vaccination was positively associated only with individual-level interaction with neighbors, with an OR of 1.55 (95% CI: 1.15, 2.08). The results indicated that vaccine uptake was associated with an individual's views of society and the social environment of the community, with substantial variations between the young and the old. Our findings emphasize the significance of public health measures to strengthen neighborhood interactions among older adults.

Evaluating the effectiveness and cost-effectiveness of free influenza vaccination policy for older adults in Yinzhou, China: Study protocol of a real-world analyses

BACKGROUND

Influenza causes excessive morbidity and mortality among older adults. While influenza vaccine provides protection against its infection, the vaccination coverage in China among older adults has been very low. Previous evidence on the cost-effectiveness of government-sponsored free influenza vaccination programs in China was primarily based on literature data, which might not always reflect real-world patient populations. The Yinzhou Health Information System (YHIS) is a regional database that captures electronic health records, insurance claims data, etc. for all residents in Yinzhou district, Zhejiang province, China. We will use YHIS to study the effectiveness, influenza-related direct medical cost and cost-effectiveness analysis (CEA) of the free influenza vaccination program for older adults. In this paper, we describe the study design and innovations in detail.

METHODS

We will establish a retrospective cohort of permanent older residents aged 65 and over, using YHIS between 2016 and 2021. We will estimate the vaccine coverage rate, influenza incidence rate and influenza-related direct medical cost from 2016 to 2021. Regression discontinuity will be used to estimate vaccine effectiveness for the 2020/2021 season. We will build a decision tree model to compare the cost-effectiveness of three influenza vaccination options (free trivalent influenza vaccine, free quadrivalent influenza vaccine, and no policy) from both societal and health system perspectives. Parameter inputs will be gathered from both YHIS and published literature. We will calculate the incremental cost-effectiveness ratio with cost and quality-adjusted life years (QALYs) discounted at 5 % annually.

DISCUSSION

Our CEA solidifies multiple sources including regional real-world data and literature for a rigorous evaluation of the government-sponsored free influenza vaccination program. The results will provide real-world evidence from real-world data on the cost-effectiveness of a real-world policy. Our findings are expected to support evidence-based policy making and to promote health for older adults.

Knowledge, Attitude, and Practice towards Influenza Vaccination among Older Adults in Southern China during the COVID-19 Pandemic

Influenza is prevalent globally, leading to severe morbidity and mortality. During the pandemic, knowledge, attitude, and practice (KAP) towards influenza virus and vaccination were less investigated among southern Chinese older adults. A cross-sectional study was conducted through the structured questionnaire among community healthcare centers in selected districts in Shenzhen, southern China from September to October 2021. KAP towards influenza virus and vaccination were analyzed. A multivariable logistic regression model was used to identify associated factors. Among 975 participants, 55.6% were reported to have received influenza vaccination ever, and 46.6% had taken influenza vaccination in 2020 during the pandemic. Only one-fifth of participants knew severe comorbidities happen among severe influenza cases. A total of 88.3% thought older adults should have influenza vaccination. COVID-19 vaccination history was associated with receiving influenza vaccination (OR 1.92, 95% CI 1.32-2.80). People with a high-level income had better KAP towards influenza virus and vaccination. COVID-19 vaccination history was associated with the positive actions of influenza vaccination during the pandemic. Efforts should be made to promote the free influenza vaccination program widely and launch health education events on influenza and its vaccination regularly to improve KAP among older adults.

Examining the Negative Sentiments Related to Influenza Vaccination from 2017 to 2022: An Unsupervised Deep Learning Analysis of 261,613 Twitter Posts

Several countries are witnessing significant increases in influenza cases and severity. Despite the availability, effectiveness and safety of influenza vaccination, vaccination coverage remains suboptimal globally. In this study, we examined the prevailing negative sentiments related to influenza vaccination via a deep learning analysis of public Twitter posts over the past five years. We extracted original tweets containing the terms 'flu jab', '#flujab', 'flu vaccine', '#fluvaccine', 'influenza vaccine', '#influenzavaccine', 'influenza jab', or '#influenzajab', and posted in English from 1 January 2017 to 1 November 2022. We then identified tweets with negative sentiment from individuals, and this was followed by topic modelling using machine learning models and qualitative thematic analysis performed independently by the study investigators. A total of 261,613 tweets were analyzed. Topic modelling and thematic analysis produced five topics grouped under two major themes: (1) criticisms of governmental policies related to influenza vaccination and (2) misinformation related to influenza vaccination. A significant majority of the tweets were centered around perceived influenza vaccine mandates or coercion to vaccinate. Our analysis of temporal trends also showed an increase in the prevalence of negative sentiments related to influenza vaccination from the year 2020 onwards, which possibly coincides with misinformation related to COVID-19 policies and vaccination. There was a typology of misperceptions and misinformation underlying the negative sentiments related to influenza vaccination. Public health communications should be mindful of these findings.

Quantifying the rebound of influenza epidemics after the adjustment of zero-COVID policy in China

The coexistence of coronavirus disease 2019 (COVID-19) and seasonal influenza epidemics has become a potential threat to human health, particularly in China in the oncoming season. However, with the relaxation of nonpharmaceutical interventions (NPIs) during the COVID-19 pandemic, the rebound extent of the influenza activities is still poorly understood. In this study, we constructed a susceptible-vaccinated-infectious-recovered-susceptible (SVIRS) model to simulate influenza transmission and calibrated it using influenza surveillance data from 2018 to 2022. We projected the influenza transmission over the next 3 years using the SVIRS model. We observed that, in epidemiological year 2021-2022, the reproduction numbers of influenza in southern and northern China were reduced by 64.0 and 34.5%, respectively, compared with those before the pandemic. The percentage of people susceptible to influenza virus increased by 138.6 and 57.3% in southern and northern China by October 1, 2022, respectively. After relaxing NPIs, the potential accumulation of susceptibility to influenza infection may lead to a large-scale influenza outbreak in the year 2022-2023, the scale of which may be affected by the intensity of the NPIs. And later relaxation of NPIs in the year 2023 would not lead to much larger rebound of influenza activities in the year 2023-2024. To control the influenza epidemic to the prepandemic level after relaxing NPIs, the influenza vaccination rates in southern and northern China should increase to 53.8 and 33.8%, respectively. Vaccination for influenza should be advocated to reduce the potential reemergence of the influenza epidemic in the next few years.

Influenza vaccine uptake among children and older adults in China: a secondary analysis of a quasi-experimental study

BACKGROUND

Influenza vaccination is the key to prevent influenza-related disease, especially among high-risk populations. However, influenza vaccine uptake in China is low. This secondary analysis of a quasi-experimental trial aimed to understand factors associated with influenza vaccine uptake among children and older people stratified by funding context.

METHODS

A total of 225 children (aged 0.5-8 years) and 225 older people (aged 60 years or above) were recruited from three clinics (rural, suburban and urban) in Guangdong Province. Participants were allocated into two groups based on funding contexts: a self-paid group (N = 150, 75 children and 75 older adults) in which participants paid full price for their vaccination; and a subsidized group (N = 300, 150 children and 150 older adults) in which varying levels of financial support was provided. Univariate and multivariable logistic regressions were conducted stratified by funding contexts.

RESULTS

Overall, 75.0% (225/300) of participants in the subsidized group and 36.7% (55/150) in the self-paid group got vaccinated. Older adults had lower vaccination rates than children in both funding groups, while both age groups showed much higher uptake in the subsidized group than in the self-paid group (aOR = 5.96, 95% CI: 3.77-9.42, p = 0.001). In the self-paid group, having prior influenza vaccination history of children (aOR:2.61, 95%CI: 1.06-6.42) or older people (aOR:4.76, 95%CI: 1.08-20.90) was associated with increased influenza vaccine uptake compared to those who had no prior vaccination experiences in the family. While in the subsidized group, participants who got married or lived with partners (aOR = 0.32, 0.10-0.98) had lower vaccination uptake than single ones. Trust in providers' advice (aOR = 4.95, 95%CI:1.99, 12.43), perceived effectiveness of the vaccine (aOR: 12.18, 95%CI: 5.21-28.50), and experienced influenza-like illnesses in the family in the past year (aOR = 46.52, 4.10, 533.78) were associated with higher vaccine uptake.

CONCLUSIONS

Older people had suboptimal vaccine uptake compared to children in both contexts and need more attention to enhance influenza vaccination. Tailoring interventions to different vaccine funding contexts may help improve influenza vaccination: In self-paid context, motivating people to accept their first ever influenza vaccination may be a promising strategy. In subsidized context, improving public confidence in vaccine effectiveness and providers' advice would be useful.

Cost-Effectiveness and Health Impacts of Different Influenza Vaccination Strategies for Children in China

INTRODUCTION

We aimed to evaluate the economic and health impacts of 3 influenza vaccines available in China, including trivalent inactivated vaccine, quadrivalent inactivated vaccine, and live attenuated influenza vaccine, for children aged 6 months to 18 years.

METHODS

Two decision-analytic models were developed to simulate 4 vaccination strategies. Outcomes included total costs from a societal perspective in 2021, quality-adjusted life-year loss, numbers of outpatient and inpatient cases, and deaths avoided using each strategy. Deterministic and probabilistic sensitivity analyses were performed to examine the uncertainty of model inputs.

RESULTS

For children aged 6 months to 3 years, trivalent inactivated vaccine saved $48 million and avoided a loss of 17,637 quality-adjusted life-years compared with no vaccination. For children aged 3-18 years, quadrivalent inactivated vaccine was cost-effective compared with trivalent inactivated vaccine, with an incremental cost-effectiveness ratio of $32,948.5/quality-adjusted life-year (willingness-to-pay threshold=$37,653/quality-adjusted life-year), which was sensitive to the RR of vaccine effectiveness of quadrivalent inactivated vaccine versus of trivalent inactivated vaccine. When compared with quadrivalent inactivated vaccine, live attenuated influenza vaccine was $1.28 billion more costly but gained an additional 13,560 quality-adjusted life-years; its incremental cost-effectiveness ratio was $123,983.8/quality-adjusted life-year. Live attenuated influenza vaccine would be cost-effective if its vaccine effectiveness was >0.79. Probabilistic sensitivity analysis revealed that quadrivalent inactivated vaccine, trivalent inactivated vaccine, live attenuated influenza vaccine, and no vaccination were cost-effective in 55.94%, 33.09%, 10.97%, and 0% of 10,000 Monte Carlo simulations.

CONCLUSIONS

Trivalent inactivated vaccine was cost-effective compared with no vaccination in children aged 6 months to 18 years. Of the 3 vaccination strategies for children aged 3-18 months, quadrivalent inactivated vaccine appears to be the most cost-effective.

Willingness to Vaccinate Against Herpes Zoster and Its Associated Factors Across WHO Regions: Global Systematic Review and Meta-Analysis

BACKGROUND

A life-course immunization approach would enhance the quality of life across all age groups and improve societal well-being. The herpes zoster (HZ) vaccine is highly recommended for older adults to prevent HZ infection and related complications. The proportions of willingness to receive the HZ vaccine varies across countries, and various kinds of factors, including sociodemographics and individual perceptions, influence the willingness to vaccinate.

OBJECTIVE

We aim to estimate the HZ vaccination willingness rate and identify factors associated with vaccine uptake willingness across all World Health Organization (WHO) regions.

METHODS

A global systematic search was performed on PubMed, Web of Science, and the Cochrane Library for all papers related to the HZ vaccine published until June 20, 2022. Study characteristics were extracted for each included study. Using double arcsine transformation, vaccination willingness rates with 95% CIs were pooled and reported. The willingness rate and associated factors were analyzed by geographical context. Associated factors were also summarized based on Health Belief Model (HBM) constructs.

RESULTS

Of the 26,942 identified records, 13 (0.05%) papers were included, covering 14,066 individuals from 8 countries in 4 WHO regions (Eastern Mediterranean Region, European Region, Region of the Americas, and Western Pacific Region). The pooled vaccination willingness rate was 55.74% (95% CI 40.85%-70.13%). Of adults aged ≥50 years, 56.06% were willing to receive the HZ vaccine. After receiving health care workers' (HCWs) recommendations, 75.19% of individuals were willing to get the HZ vaccine; without HCWs' recommendations, the willingness rate was only 49.39%. The willingness rate was more than 70% in the Eastern Mediterranean Region and approximately 55% in the Western Pacific Region. The willingness rate was the highest in the United Arab Emirates and the lowest in China and the United Kingdom. The perception of HZ severity and susceptibility was positively associated with vaccination willingness. The perceived barriers to vaccination willingness (main reasons for unwillingness) included low trust in the effectiveness of the HZ vaccine, concerns about safety, financial concerns, and being unaware of the HZ vaccine's availability. Older individuals, those having lower education, or those having lower income levels were less likely to willing to be vaccinated.

CONCLUSIONS

Only 1 in 2 individuals showed a willingness to be vaccinated against HZ. The willingness rate was the highest in the Eastern Mediterranean Region. Our findings show the critical role HCWs play in promoting HZ vaccination. Monitoring HZ vaccination willingness is necessary to inform public health decision-making. These findings provide critical insights for designing future life-course immunization programs.

Regional characteristics of influenza seasonality patterns in mainland China, 2005-2017: a statistical modeling study

OBJECTIVES

To quantify the seasonal and antigenic characteristics of influenza to help understand influenza activity and inform vaccine recommendations.

METHODS

We employed a generalized linear model with harmonic terms to quantify the seasonal pattern of influenza in China from 2005-2017, including amplitude (circulatory intensity), semiannual periodicity (given two peaks a year), annual peak time, and epidemic duration. The antigenic differences were distinguished as antigenic similarity between 2009 and 2020. We categorized regions above 33° N, between 27° N and 33° N, and below 27° N as the north, central, and south regions, respectively.

RESULTS

We estimated that the amplitude in the north region (median: 0.019, 95% CI: 0.018-0.021) was significantly higher than that in the central region (median: 0.011, 95% CI: 0.01-0.012, P <0.001) and south region (median: 0.008, 95% CI: 0.007-0.008, P <0.001) for influenza A virus subtype H3N2 (A/H3N2). The A/H3N2 in the central region had a semiannual periodicity (median: 0.548, 95% CI: 0.517-0.577), while no semiannual pattern was found in other regions or subtypes/lineages. The antigenic similarity was low (below 50% in the 2009-2010, 2014-2015, 2016-2018, and 2019-2020 seasons) for A/H3N2.

CONCLUSION

Our study depicted the seasonal pattern differences and antigenic differences of influenza in China, which provides information for vaccination strategies.

Influenza-Associated Excess Mortality by Age, Sex, and Subtype/Lineage: Population-Based Time-Series Study With a Distributed-Lag Nonlinear Model

BACKGROUND

Accurate estimation of the influenza death burden is of great significance for influenza prevention and control. However, few studies have considered the short-term harvesting effects of influenza on mortality when estimating influenza-associated excess deaths by cause of death, age, sex, and subtype/lineage.

OBJECTIVE

This study aimed to estimate the cause-, age-, and sex-specific excess mortality associated with influenza and its subtypes and lineages in Guangzhou from 2015 to 2018.

METHODS

Distributed-lag nonlinear models were fitted to estimate the excess mortality related to influenza subtypes or lineages for different causes of death, age groups, and sex based on daily time-series data for mortality, influenza, and meteorological factors.

RESULTS

A total of 199,777 death certificates were included in the study. The average annual influenza-associated excess mortality rate (EMR) was 25.06 (95% empirical CI [eCI] 19.85-30.16) per 100,000 persons; 7142 of 8791 (81.2%) deaths were due to respiratory or cardiovascular mortality (EMR 20.36, 95% eCI 16.75-23.74). Excess respiratory and cardiovascular deaths in people aged 60 to 79 years and those aged ≥80 years accounted for 32.9% (2346/7142) and 63.7% (4549/7142) of deaths, respectively. The male to female ratio (MFR) of excess death from respiratory diseases was 1.34 (95% CI 1.17-1.54), while the MFR for excess death from cardiovascular disease was 0.72 (95% CI 0.63-0.82). The average annual excess respiratory and cardiovascular mortality rates attributed to influenza A (H3N2), B/Yamagata, B/Victoria, and A (H1N1) were 8.47 (95% eCI 6.60-10.30), 5.81 (95% eCI 3.35-8.25), 3.68 (95% eCI 0.81-6.49), and 2.83 (95% eCI -1.26 to 6.71), respectively. Among these influenza subtypes/lineages, A (H3N2) had the highest excess respiratory and cardiovascular mortality rates for people aged 60 to 79 years (20.22, 95% eCI 14.56-25.63) and ≥80 years (180.15, 95% eCI 130.75-227.38), while younger people were more affected by A (H1N1), with an EMR of 1.29 (95% eCI 0.07-2.32). The mortality displacement of influenza A (H1N1), A (H3N2), and B/Yamagata was 2 to 5 days, but 5 to 13 days for B/Victoria.

CONCLUSIONS

Influenza was associated with substantial mortality in Guangzhou, occurring predominantly in the elderly, even after considering mortality displacement. The mortality burden of influenza B, particularly B/Yamagata, cannot be ignored. Contrasting sex differences were found in influenza-associated excess mortality from respiratory diseases and from cardiovascular diseases; the underlying mechanisms need to be investigated in future studies. Our findings can help us better understand the magnitude and time-course of the effect of influenza on mortality and inform targeted interventions for mitigating the influenza mortality burden, such as immunizations with quadrivalent vaccines (especially for older people), behavioral campaigns, and treatment strategies.

Short-term effects of ambient particulate matter (PM1, PM2.5 and PM10) on influenza-like illness in Guangzhou, China

BACKGROUND

Particulate matter (PM) has been linked to respiratory infections in a growing body of evidence. Studies on the relationship between ILI (influenza-like illness) and PM₁ (particulate matter with aerodynamic diameter ≤1 μm) are, however, scarce. The purpose of this study was to investigate the effects of PM on ILI in Guangzhou, China.

METHODS

Daily ILI cases, air pollution records (PM₁, PM_2.5, PM₁₀ and gaseous pollutants), and metrological data between 2014 and 2019 were gathered from Guangzhou, China. To estimate the risk of ILI linked with exposure to PM pollutants, a quasi-Poisson regression was used. Additionally, subgroup analyses stratified by gender, age and season were carried out.

RESULTS

For each 10 μg/m³ increase of PM₁ and PM_2.5 over the past two days (lag01), and PM₁₀ over the past three days (lag02), the relative risks (RR) of ILI were 1.079 (95% confidence interval [CI]: 1.050, 1.109), 1.044 (95% CI: 1.027, 1.062) and 1.046 (95% CI: 1.032, 1.059), respectively. The estimated risks for men and women were substantially similar. The effects of PM pollutants between male and female were basically equivalent. People aged 15-24 years old were more susceptive to PM pollutants.

CONCLUSIONS

It implies that PM₁, PM_2.5 and PM₁₀ are all risk factors for ILI, the health impacts of PM pollutants vary by particle size. Reducing the concentration of PM₁ needs to be considered when generating a strategy to prevent ILI.

Epidemiological features and trends in the mortality rates of 10 notifiable respiratory infectious diseases in China from 2004 to 2020: Based on national surveillance

Objectives

The aim of this study is to describe, visualize, and compare the trends and epidemiological features of the mortality rates of 10 notifiable respiratory infectious diseases in China from 2004 to 2020.

Setting

Data were obtained from the database of the National Infectious Disease Surveillance System (NIDSS) and reports released by the National and local Health Commissions from 2004 to 2020. Spearman correlations and Joinpoint regression models were used to quantify the temporal trends of RIDs by calculating annual percentage changes (APCs) in the rates of mortality.

Results

The overall mortality rate of RIDs was stable across China from 2004 to 2020 (R = -0.38, P = 0.13), with an APC per year of -2.2% (95% CI: -4.6 to 0.3; P = 0.1000). However, the overall mortality rate of 10 RIDs in 2020 decreased by 31.80% (P = 0.006) compared to the previous 5 years before the COVID-19 pandemic. The highest mortality occurred in northwestern, western, and northern China. Tuberculosis was the leading cause of RID mortality, and mortality from tuberculosis was relatively stable throughout the 17 years (R = -0.36, P = 0.16), with an APC of -1.9% (95% CI -4.1 to 0.4, P = 0.1000). Seasonal influenza was the only disease for which mortality significantly increased (R = 0.73, P = 0.00089), with an APC of 29.70% (95% CI 16.60-44.40%; P = 0.0000). The highest yearly case fatality ratios (CFR) belong to avian influenza A H5N1 [687.5 per 1,000 (33/48)] and epidemic cerebrospinal meningitis [90.5748 per 1,000 (1,010/11,151)]. The age-specific CFR of 10 RIDs was highest among people over 85 years old [13.6551 per 1,000 (2,353/172,316)] and was lowest among children younger than 10 years, particularly in 5-year-old children [0.0552 per 1,000 (58/1,051,178)].

Conclusions

The mortality rates of 10 RIDs were relatively stable from 2004 to 2020 with significant differences among Chinese provinces and age groups. There was an increased mortality trend for seasonal influenza and concerted efforts are needed to reduce the mortality rate of seasonal influenza in the future.

Influenza and Universal Vaccine Research in China

Influenza viruses usually cause seasonal influenza epidemics and influenza pandemics, resulting in acute respiratory illness and, in severe cases, multiple organ complications and even death, posing a serious global and human health burden. Compared with other countries, China has a large population base and a large number of influenza cases and deaths. Currently, influenza vaccination remains the most cost-effective and efficient way to prevent and control influenza, which can significantly reduce the risk of influenza virus infection and serious complications. The antigenicity of the influenza vaccine exhibits good protective efficacy when matched to the seasonal epidemic strain. However, when influenza viruses undergo rapid and sustained antigenic drift resulting in a mismatch between the vaccine strain and the epidemic strain, the protective effect is greatly reduced. As a result, the flu vaccine must be reformulated and readministered annually, causing a significant drain on human and financial resources. Therefore, the development of a universal influenza vaccine is necessary for the complete fight against the influenza virus. By statistically analyzing cases related to influenza virus infection and death in China in recent years, this paper describes the existing marketed vaccines, vaccine distribution and vaccination in China and summarizes the candidate immunogens designed based on the structure of influenza virus, hoping to provide ideas for the design and development of new influenza vaccines in the future.

Influence of air pollution on influenza-like illness in China: a nationwide time-series analysis

BACKGROUND

Evidence concerning effects of air pollution on influenza-like illness (ILI) from multi-center is limited and little is known about how regional factors might modify this relationship.

METHODS

In this ecological study, ILI cases defined as outpatients with temperature ≥38 °C, accompanied by cough or sore throat, were collected from National Influenza Surveillance Network in China. We adopted generalized additive model with quasi-Poisson to estimate province-specific association between air pollution and ILI in 30 Chinese provinces during 2015-2019, after adjusting for time trend and meteorological factors. We then pooled province-specific association by using random-effect meta-analysis. Potential effect modifications of season and regional characteristics were explored.

FINDINGS

A total of 26, 004, 853 ILI cases and 777, 223, 877 hospital outpatients were collected. In general, effects of air pollutants were acute. An inter-quartile range increase of PM_2.5, SO₂, PM₁₀, NO₂ and CO at lag0, and O₃ at lag0-2 was associated with 3.08% (95% CI: 1.91%, 4.27%), 3.00% (1.86%, 4.16%), 6.46% (4.71%, 8.25%), 7.21% (5.73%, 8.71%), 4.37% (3.05%, 5.70%), and -9.26% (-11.32%, -7.14%) change of ILI at national level, respectively. Associations between air pollutants and ILI varied by season and regions, with higher effect estimates in cold season, eastern and central regions and provinces with more humid condition and larger population.

INTERPRETATION

This study indicated that most air pollutants increased the risk of ILI in China. Our findings might provide implications for the development of policies to protect public health from air pollution and influenza.

FUNDING

National Natural Science Foundation of China and Chongqing Health Commission Program.

Mechanisms for the circulation of influenza A(H3N2) in China: A spatiotemporal modelling study

Circulation of seasonal influenza is the product of complex interplay among multiple drivers, yet characterizing the underlying mechanism remains challenging. Leveraging the diverse seasonality of A(H3N2) virus and abundant climatic space across regions in China, we quantitatively investigated the relative importance of population susceptibility, climatic factors, and antigenic change on the dynamics of influenza A(H3N2) through an integrative modelling framework. Specifically, an absolute humidity driven multiscale transmission model was constructed for the 2013/2014, 2014/2015 and 2016/2017 influenza seasons that were dominated by influenza A(H3N2). We revealed the variable impact of absolute humidity on influenza transmission and differences in the occurring timing and magnitude of antigenic change for those three seasons. Overall, the initial population susceptibility, climatic factors, and antigenic change explained nearly 55% of variations in the dynamics of influenza A(H3N2). Specifically, the additional variation explained by the initial population susceptibility, climatic factors, and antigenic change were at 33%, 26%, and 48%, respectively. The vaccination program alone failed to fully eliminate the summer epidemics of influenza A(H3N2) and non-pharmacological interventions were needed to suppress the summer circulation. The quantitative understanding of the interplay among driving factors on the circulation of influenza A(H3N2) highlights the importance of simultaneous monitoring of fluctuations for related factors, which is crucial for precise and targeted prevention and control of seasonal influenza.

Study on the influence of meteorological factors on influenza in different regions and predictions based on an LSTM algorithm

BACKGROUND

Influenza epidemics pose a threat to human health. It has been reported that meteorological factors (MFs) are associated with influenza. This study aimed to explore the similarities and differences between the influences of more comprehensive MFs on influenza in cities with different economic, geographical and climatic characteristics in Fujian Province. Then, the information was used to predict the daily number of cases of influenza in various cities based on MFs to provide bases for early warning systems and outbreak prevention.

METHOD

Distributed lag nonlinear models (DLNMs) were used to analyse the influence of MFs on influenza in different regions of Fujian Province from 2010 to 2021. Long short-term memory (LSTM) was used to train and model daily cases of influenza in 2010-2018, 2010-2019, and 2010-2020 based on meteorological daily values. Daily cases of influenza in 2019, 2020 and 2021 were predicted. The root mean squared error (RMSE), mean absolute error (MAE), mean absolute percentage error (MAPE) and symmetric mean absolute percentage error (SMAPE) were used to quantify the accuracy of model predictions.

RESULTS

The cumulative effect of low and high values of air pressure (PRS), air temperature (TEM), air temperature difference (TEMD) and sunshine duration (SSD) on the risk of influenza was obvious. Low (< 979 hPa), medium (983 to 987 hPa) and high (> 112 hPa) PRS were associated with a higher risk of influenza in women, children aged 0 to 12 years, and rural populations. Low (< 9 °C) and high (> 23 °C) TEM were risk factors for influenza in four cities. Wind speed (WIN) had a more significant effect on the risk of influenza in the ≥ 60-year-old group. Low (< 40%) and high (> 80%) relative humidity (RHU) in Fuzhou and Xiamen had a significant effect on influenza. When PRS was between 1005-1015 hPa, RHU > 60%, PRE was low, TEM was between 10-20 °C, and WIN was low, the interaction between different MFs and influenza was most obvious. The RMSE, MAE, MAPE, and SMAPE evaluation indices of the predictions in 2019, 2020 and 2021 were low, and the prediction accuracy was high.

CONCLUSION

All eight MFs studied had an impact on influenza in four cities, but there were similarities and differences. The LSTM model, combined with these eight MFs, was highly accurate in predicting the daily cases of influenza. These MFs and prediction models could be incorporated into the influenza early warning and prediction system of each city and used as a reference to formulate prevention strategies for relevant departments.

Parental Seasonal Influenza Vaccine Hesitancy and Associated Factors in Shanghai, China, during the COVID-19 Pandemic: A Cross-Sectional Study

BACKGROUND

Seasonal influenza may overlap with the COVID-19 pandemic, and children are one of the priority populations for influenza vaccination in China, yet vaccine coverage has been low. This study aimed to investigate the extent of parental influenza vaccine hesitancy (IVH) and to explore the associated factors.

METHODS

The study was conducted in Shanghai, China, from 1 June 2022 to 31 July 2022, using an anonymous questionnaire to survey a random sample of parents of children aged six months to 14 years. Binary logistic regression models were used to identify factors associated with IVH.

RESULTS

Of the 5016 parents, 34.05% had IVH. Multivariate analysis showed that after adjustment for non-modifiable markers (i.e., sociodemographic, health status, and past vaccination status), being affected by negative influenza vaccine news and having higher "complacency" were positively associated with parental IVH. Higher knowledge of influenza vaccination, being recommended by healthcare workers (HCWs), people around having a positive attitude toward influenza vaccine and having higher levels of "confidence" and "convenience" were negatively associated with parental IVH.

CONCLUSIONS

In China, public health education aimed at modifying vaccination-related attitudes and beliefs, as well as knowledge and societal influences, could help reduce influenza vaccination hesitancy.

Influenza vaccination coverage among health-care workers during the COVID-19 epidemic in 2020/2021 influenza season: Evidence from a web-based survey in northwestern China

Vaccinating health-care workers against influenza during the COVID-19 pandemic can effectively prevent and control influenza and reduce COVID-19 strain on health systems. This study was conducted to explore influenza vaccination coverage and determinants among health-care workers during the COVID-19 pandemic in 2020/2021 influenza season in Ningxia. This cross-sectional survey included demographic characteristics of health-care workers, influenza vaccination status, reasons for not getting vaccinated, and whether influenza vaccination was recommended for others. We found that influenza vaccine rate of health-care workers was 39.6%. A binary logistic regression analysis showed that health-care workers' vaccination coverage was higher when the individuals were aware of the effect of the influenza vaccine (OR = 0.624, 95% CI: 0.486-0.802). Health-care workers who from internal medicine (OR = 1.494, 95% CI: 1.146-1.948), pediatrics (OR = 2.091, 95% CI: 1.476-2.962), and surgery departments (OR = 1.373, 95% CI: 1.014-1.859) had a lower coverage than those who worked in vaccination and infectious disease departments. The main reasons that some stated for not getting vaccinated were that they felt it was unnecessary (52.22%). Health-care workers who were vaccinated against influenza were more likely to recommend influenza vaccination to their patients than health-care workers who had not been vaccinated. The incidence of influenza among health-care workers was higher than that of the general population in Ningxia. Under the policy of voluntary and self-pay influenza vaccination in Ningxia, the coverage rate of influenza vaccine among health-care workers was far below the vaccination requirements of influenza vaccine in influenza season even during the COVID-19 epidemic.

Vaccine Uptake to Prevent Meningitis and Encephalitis in Shanghai, China

Multiple vaccines may prevent meningitis and encephalitis (M/E). In China, the meningococcal vaccine and Japanese encephalitis vaccine (JEV) have been included in the expanded program of immunization (EPI). The pneumococcal vaccine, Haemophilus influenzae type b (Hib) vaccine, rotavirus vaccine, and enterovirus 71 (EV-71) vaccine are non-EPI vaccines and are self-paid. We aim to investigate the uptake of these M/E vaccines in children and the related knowledge and health beliefs among family caregivers. A total of 1011 family caregivers with children aged 1-6 years in Shanghai, China were included in the study. The uptake of the pneumococcal vaccine, Hib-containing vaccine, rotavirus vaccine, and EV-71 vaccine remained at 44.0-48.1% in children, compared with the higher uptake of the meningococcal vaccine (88.8%) and JEV (87.1%). Moreover, family caregivers had limited knowledge on the M/E pathogens and possible vaccines. Their health beliefs were moderate to high. Then, a health belief model (HBM) and a structural equation model were established. The uptake of four non-EPI vaccines was significantly influenced by family income (β = 0.159), knowledge (β = 0.354), self-efficacy (β = 0.584), and perceived susceptibility (β = 0.212) within an HBM. Therefore, it warrants further improving the uptake rate for these non-EPI vaccines to prevent potential M/E in children. A specific health promotion may empower the caregivers' decision-making on childhood vaccination.

The Impact of Urbanization and Human Mobility on Seasonal Influenza in Northern China

The intensity of influenza epidemics varies significantly from year to year among regions with similar climatic conditions and populations. However, the underlying mechanisms of the temporal and spatial variations remain unclear. We investigated the impact of urbanization and public transportation size on influenza activity. We used 6-year weekly provincial-level surveillance data of influenza-like disease incidence (ILI) and viral activity in northern China. We derived the transmission potential of influenza for each epidemic season using the susceptible-exposed-infectious-removed-susceptible (SEIRS) model and estimated the transmissibility in the peak period via the instantaneous reproduction number (R_t). Public transport was found to explain approximately 28% of the variance in the seasonal transmission potential. Urbanization and public transportation size explained approximately 10% and 21% of the variance in maximum R_t in the peak period, respectively. For the mean R_t during the peak period, urbanization and public transportation accounted for 9% and 16% of the variance in R_t, respectively. Our results indicated that the differences in the intensity of influenza epidemics among the northern provinces of China were partially driven by urbanization and public transport size. These findings are beneficial for predicting influenza intensity and developing preparedness strategies for the early stages of epidemics.

Employee Participation in Workplace Vaccination Campaigns: A Systematic Review and Meta-Analysis

To reduce vaccine-preventable diseases in workers, workplace vaccination campaigns can be implemented on-site. The aim of this systematic review was to evaluate adherence to workplace vaccination campaigns. Three databases, PubMed, ISI Web of Science, and Scopus, were screened systematically for articles in English or Italian addressing participation in an on-site vaccination program by employees. The following data was extracted: authors, year, country, type of vaccine, type of workplace, sample size, vaccination rate. Data on the prevalence of flu vaccination were calculated and pooled using a random-effects model. Thirteen articles were included in the review, ten in the meta-analysis. Most studies were conducted in the USA (30.7%) and most vaccination campaigns were against influenza (69.2%), with a pooled estimate of 42% (95% CI: 0.25-0.60%); participation rate was highly variable, ranging from 88.9% for an influenza vaccination campaign to 5.7% for a Lyme disease vaccination campaign. Offering free on-site vaccination can be a successful tool to ensure adherence to vaccination campaigns and administration of all required doses according to the vaccine administration scheme. The occupational physician can play a key role in implementing workplace campaigns for employee mandatory vaccinations.

Caregiver Willingness to Vaccinate Children with Pneumococcal Vaccines and to Pay in a Low-Resource Setting in China: A Cross-Sectional Study

To determine the vaccine hesitancy of pneumococcal conjugate vaccines (PCVs) in a low-resource setting in China and to identify associated factors, a face-to-face questionnaire survey was conducted in the city of Guilin, China, from December 2021 to March 2022, which comprised sociodemographic information, attitudes toward vaccines and pneumonia, and PCV13 vaccination willingness and willingness to pay (WTP). Stepwise logistic regression and Tobit regression models were fitted to identify factors associated with PCV13 vaccination willingness and WTP, respectively. In total, 1254 questionnaires were included, of which 899, 254, and 101 participants showed acceptance, hesitancy, and refusal to vaccinate their children with PCV13, respectively. Only 39.07% of participants knew about PCV13 before this survey. A total of 558 (48.40%) participants accepted the full payment of vaccination, and 477 (41.37%) other participants accepted the partial payment, with a median cost of CNY 920.00. Demographics, social and psychological context, and attitudes toward vaccines were all associated with PCV13 vaccination but varied for hesitators and refusers. There is a substantial local demand for vaccinating children with PCV13 and partial payment is widely accepted. More publicity and educational efforts and a socially supportive environment are required to alleviate vaccine hesitancy.

The Epidemiology of Influenza and the Associated Vaccines Development in China: A Review

Influenza prevention and control has been one of the biggest challenges encountered in the public health domain. The vaccination against influenza plays a pivotal role in the prevention of influenza, particularly for the elderly and small children. According to the epidemiology of influenza in China, the nation is under a heavy burden of this disease. Therefore, as a contribution to the prevention and control of influenza in China through the provision of relevant information, the present report discusses the production and batch issuance of the influenza vaccine, analysis of the vaccination status and vaccination rate of the influenza vaccine, and the development trend of the influenza vaccine in China.