Changes in the Epidemiological Features of Influenza After the COVID-19 Pandemic in China, the United States, and Australia: Updated Surveillance Data for Influenza Activity.

BACKGROUND: There has been a global decrease in seasonal influenza activity since the onset of the COVID-19 pandemic. OBJECTIVE: We aimed to describe influenza activity during the 2021/2022 season and compare it to the trends from 2012 to 2023. We also explored the influence of social and public health prevention measures during the COVID-19 pandemic on influenza activity. METHODS: We obtained influenza data from January 1, 2012, to February 5, 2023, from publicly available platforms for China, the United States, and Australia. Mitigation measures were evaluated per the stringency index, a composite index with 9 measures. A general additive model was used to assess the stringency index and the influenza positivity rate correlation, and the deviance explained was calculated. RESULTS: We used over 200,000 influenza surveillance data. Influenza activity remained low in the United States and Australia during the 2021/2022 season. However, it increased in the United States with a positive rate of 26.2% in the 49th week of 2022. During the 2021/2022 season, influenza activity significantly increased compared with the previous year in southern and northern China, with peak positivity rates of 28.1% and 35.1% in the second week of 2022, respectively. After the COVID-19 pandemic, the dominant influenza virus genotype in China was type B/Victoria, during the 2021/2022 season, and accounted for >98% (24,541/24,908 in the South and 20,543/20,634 in the North) of all cases. Influenza virus type B/Yamagata was not detected in all these areas after the COVID-19 pandemic. Several measures individually significantly influence local influenza activity, except for influenza type B in Australia. When combined with all the measures, the deviance explained values for influenza A and B were 87.4% (P<.05 for measures of close public transport and restrictions on international travel) and 77.6% in southern China and 83.4% (P<.05 for measures of school closing and close public transport) and 81.4% in northern China, respectively. In the United States, the association was relatively stronger, with deviance-explained values of 98.6% for influenza A and 99.1% (P<.05 for measures of restrictions on international travel and public information campaign) for influenza B. There were no discernible effects on influenza B activity in Australia between 2020 and 2022 due to the incredibly low positive rate of influenza B. Additionally, the deviance explained values were 95.8% (P<.05 for measures of restrictions on gathering size and restrictions on international travel) for influenza A and 72.7% for influenza B. CONCLUSIONS: Influenza activity has increased gradually since 2021. Mitigation measures for COVID-19 showed correlations with influenza activity, mainly driven by the early stage of the pandemic. During late 2021 and 2022, the influence of mitigation management for COVID-19 seemingly decreased gradually, as the activity of influenza increased compared to the 2020/2021 season.

Estimated number and incidence of influenza-associated acute respiratory infection cases in winter 2021/22 in Wanzhou District, China.

OBJECTIVES: Understanding the burden of influenza-associated acute respiratory infection (ARI) and severe ARI (SARI) is crucial for public health decision-making. A population-based study with multiple data sources was conducted to estimate the burden of influenza-associated ARI in Wanzhou District, Chongqing, southern China. STUDY DESIGN: Population-based surveillance study. METHODS: Active surveillance of ARI was conducted in different levels of health facilities in the Wanzhou District between October 2021 and March 2022. Nasal or throat swabs were collected and tested for influenza viruses in hospital-based surveillance. A health utilisation survey was used to estimate health-seeking behaviour, and all electronic medical records were collected. An epidemiological model was used to estimate the disease burden. RESULTS: There were an estimated 52,960 influenza-associated ARI (95 % confidence interval [CI]: 39,213-84,891), including 2,529 SARI cases (95 % CI: 1,385-21,712) during winter 2021/22 in the Wanzhou District. The incidence rate for all influenza-associated ARI and SARI was 3,385/100,000 and 162/100,000, respectively. A higher incidence rate of influenza-associated ARI was observed among individuals aged <50 years, while a higher influenza-associated SARI rate was observed in those aged ≥50 years. CONCLUSIONS: Using an epidemiological model with data from multiple sources, this study documented a substantial burden of influenza-associated ARI in the Wanzhou District, highlighting the need for influenza vaccination and providing a possible foundation for public health decision-making.

Effectiveness of influenza vaccines in preventing acute cardiovascular events within 1 year in Beijing, China.

Controversies persist about the protective effects of vaccines against acute cardiovascular events. Using electronic medical records from hospitals and influenza vaccine administration data in Beijing, China, we studied individuals vaccinated between January 1, 2016, and December 31, 2018, who experienced at least one acute cardiovascular event within two years. A self-controlled case series design calculated the relative incidence (RI) and 95% confidence interval (CI) of acute cardiovascular events within one year after vaccination. Among 1647 participants (median age: 65 years, 38.43% female), the risk of events 29-365 days post-vaccination was 0.76 times the baseline level (RI: 0.76; 95% CI: 0.68-0.84). The protective effect was more pronounced in younger participants (P = 0.043) and those without cardiovascular history (P < 0.001), while acute respiratory infection (P = 0.986) and vaccination frequency (P = 0.272) had no impact. Influenza vaccines offer protection against acute cardiovascular events for at least one year, suggesting potential for cardiovascular disease prevention.

Mapping the Characteristics of Respiratory Infectious Disease Epidemics in China Based on the Baidu Index from November 2022 to January 2023.

Introduction: Infectious diseases pose a significant global health and economic burden, underscoring the critical need for precise predictive models. The Baidu index provides enhanced real-time surveillance capabilities that augment traditional systems. Methods: Baidu search engine data on the keyword "fever" were extracted from 255 cities in China from November 2022 to January 2023. Onset and peak dates for influenza epidemics were identified by testing various criteria that combined thresholds and consecutive days. Results: The most effective scenario for indicating epidemic commencement involved a 90th percentile threshold exceeded for seven consecutive days, minimizing false starts. Peak detection was optimized using a 7-day moving average, balancing stability and precision. Discussion: The use of internet search data, such as the Baidu index, significantly improves the timeliness and accuracy of disease surveillance models. This innovative approach supports faster public health interventions and demonstrates its potential for enhancing epidemic monitoring and response efforts.

Increasing Influenza Vaccination Rates among Patients with Type 2 Diabetes Mellitus in Chongqing, China: A Cross-Sectional Analysis Using Behavioral and Social Drivers Tools.

BACKGROUND: Influenza vaccination is essential for type 2 diabetes mellitus (T2DM) patients due to their higher risks of severe complications and mortality from influenza. This study investigated the willingness of T2DM patients in Chongqing, China, to receive the influenza vaccination during the 2023/2024 season, using behavioral and social drivers (BeSD) tools to improve vaccination uptake in this high-risk group. METHODS: A multi-stage sampling method was used to select participants, and face-to-face surveys were conducted in community health centers between March 1 and May 1, 2023. Binary logistic regression was used to analyze the factors influencing vaccination willingness, and standardized scores identified barriers and drivers. RESULTS: Among 1672 T2DM patients, 11.7% had been vaccinated during the 2022/2023 season, and 59.6% were willing to receive the vaccination in the 2023/2024 season. Higher willingness was associated with ethnic minorities (odds ratio [OR], 3.18, 95% confidence interval [CI]: 1.58-6.39), being unemployed individuals (OR 2.69, 95% CI: 1.60-4.52), higher monthly household income per capita (OR 2.72, 95% CI: 1.65-4.50), having diabetes complications (OR 1.76, 95% CI: 1.23-2.51), sufficient vaccine knowledge (OR 1.87, 95% CI: 1.48-2.37), and previous vaccination (OR 7.75, 95% CI: 4.83-12.44). Concerning BeSDs, fear of infecting friends or family members and trust in vaccine efficacy were the predominant drivers, while high vaccine costs were the greatest barrier. CONCLUSIONS: Future strategies should focus on improving vaccine knowledge, supporting healthcare workers and peer recommendations, and enhancing vaccination policies. Key interventions such as health education among high-risk groups, such as unemployed individuals, advocacy campaigns, pay-it-forward strategies, and policies for free vaccination could improve coverage in Chongqing.

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.

Pathogen characteristics of respiratory infections in the season after the COVID-19 pandemic between August and December 2023: evidence from direct-to-consumer testing-based surveillance in Guangzhou and Beijing, China.

OBJECTIVES: In the fall-winter of 2023, China experienced its first epidemic season of respiratory diseases since the COVID-19 pandemic. Gathering timely data about pathogenetic characteristics of respiratory infections is crucial to complement current respiratory surveillance mechanisms in China. Data from direct-to-consumer (DTC) multi-respiratory pathogen (MRP) testing could serve as a novel source of multi-pathogen data for community-based surveillance. METHODS: A pioneering initiative was launched to detect multiple respiratory pathogens in Beijing and Guangzhou, China. DTC MRP tests were used to provide proactive surveillance ahead of medical services. RESULTS: A total of 28,018 participants were enrolled between 22 August and 10 December 2023. Positive findings for at least one respiratory pathogen were observed in 26,202 (93.5%) participants. Influenza virus A, respiratory syncytial virus (RSV), and human adenovirus are the three leading viral pathogens detected with proportions of 18.0%, 10.6%, and 8.8%. Viral-bacterial pathogens were co-detected in 9736 (34.7%) of participants, which reduced to 22.2% for bacterial-bacterial co-detection, and 22.0% for bacterial mono-detection. The epidemiological ecology of respiratory pathogens within both viral clusters and specific pathogens varied among cities. The peak of RSV epidemics in Guangzhou occurred in the fall of 2023, earlier than in Beijing. CONCLUSION: The innovative program offered enhanced surveillance capabilities beyond traditional methods, enabling prompt feedback about test results and mitigating the risk of cross-infection caused by waits in healthcare facilities.

Development and validation of a COVID-19 vaccination prediction model based on self-reporting results in Chinese older adults from September 2022 to November 2022: A nationwide cross-sectional study.

It was common to see that older adults were reluctant to be vaccinated for coronavirus disease 2019 (COVID-19) in China. There is a lack of practical prediction models to guide COVID-19 vaccination program. A nationwide, self-reported, cross-sectional survey was conducted from September 2022 to November 2022, including people aged 60 years or older. Stratified random sampling was used to divide the dataset into derivation, validation, and test datasets at a ratio of 6:2:2. Least absolute shrinkage and selection operator and multivariable logistic regression were used for variable screening and model construction. Discrimination and calibration were assessed primarily by area under the receiver operating characteristic curve (AUC) and calibration curve. A total of 35057 samples (53.65% males and mean age of 69.64 ± 7.24 years) were finally selected, which constitutes 93.73% of the valid samples. From 33 potential predictors, 19 variables were screened and included in the multivariable logistic regression model. The mean AUC in the validation dataset was 0.802, with sensitivity, specificity, and accuracy of 0.732, 0.718 and 0.729 respectively, which were similar to the parameters in the test dataset of 0.755, 0.715 and 0.720, respectively, and the mean AUC in the test dataset was 0.815. There were no significant differences between the model predicted values and the actual observed values for calibration in these groups. The prediction model based on self-reported characteristics of older adults was developed that could be useful for predicting the willingness for COVID-19 vaccines, as well as providing recommendations in improving vaccine acceptance.

Association between influenza vaccination and one-year all-cause and cardiovascular mortality risk: A self-controlled case series and matched case-control study.

Debates surrounding the efficacy of influenza vaccination for survival benefits persist, and there is a lack of data regarding its duration of protection. A self-controlled case series (SCCS) and a 1:4 matched case-control study were conducted using the National Health Interview Survey (NHIS) and public-use mortality data from 2005 to 2018 in the United States. The SCCS study identified participants who received influenza vaccination within 12 months before the survey and subsequently died within 1 year of postvaccination. The matched case-control study paired participants who died during the influenza season at the time of survey with four survivors. Among 1167 participants in the SCCS study, there was a 46% reduction in all-cause mortality and a 43% reduction in cardiovascular mortality within 29-196 days of postvaccination. The greatest protection was observed during days 29-56 (all-cause mortality: RI: 0.19; 95% CI: 0.12-0.29; cardiovascular mortality: RI: 0.28; 95% CI: 0.14-0.56). Among 626 cases and 2504 controls included in the matched case-control study, influenza vaccination was associated with a reduction in all-cause mortality (OR: 0.74, 95% CI: 0.60-0.92) and cardiovascular mortality (OR: 0.64, 95% CI: 0.44-0.93) during the influenza season. This study highlights the importance of influenza vaccination in reducing the risks of all-cause and cardiovascular mortality, with effects lasting for approximately 6 months.

An effectiveness study of vaccination and quarantine combination strategies for containing mpox transmission on simulated college campuses.

The ongoing transmission of mpox in specific countries and regions necessitates urgent action. It is essential to implement targeted containment strategies that concentrate on high-risk populations and critical locations, such as college campuses, to effectively curb the spread of mpox. This study is dedicated to evaluating the performance of various vaccination and quarantine strategies in curbing the spread of mpox and estimating the outbreak risk. To accomplish this, we constructed a stochastic, agent-based, discrete-time susceptible-latent-infectious-recovered (SLIR) model, to examine mpox transmission on a simulated college campus. Our findings reveal that relying solely on PEP is insufficient in containing mpox effectively. To bolster the population immunity and protect the vulnerable, pre-exposure vaccination among high-risk populations prior to an outbreak is imperative. Our study demonstrates that a pre-exposure vaccination rate of 50% in high-risk populations can led to a remarkable 74.2% reduction of infections. This translated to a mere 1.0% cumulative infection incidence in the overall population. In cases where the desired vaccination coverage is not attainable, enhancing case detection and isolation measures can serve as an effective emergency response to contain mpox outbreaks. For pre-exposure vaccination coverage of 20% or lower, a 40% isolation ratio is necessary to keep the cumulative number of infections in check. However, when the coverage exceeds 30%, a reduced isolation ratio of 20% becomes sufficient to manage the outbreak effectively. These insights underscore the importance of strategic pre-exposure vaccination in conjunction with robust surveillance and isolation protocols to safeguard public health and prevent the escalation of mpox outbreaks.

A Large-Scale Online Survey on Clinical Severity and Associated Risk Factors for SARS-CoV-2 Omicron Infection - China, April-May 2023.

What is already known about this topic?: Individuals who initially contract severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) lack significant mixed immunity. Therefore, it is crucial to monitor the clinical characteristics and associated factors of these individuals in order to inform policy-making. What is added by this report?: The common symptoms reported were fever, cough, and sore throat. Reinfections and receiving four vaccination doses within a 6-month period were found to be associated with a shorter duration of virus shedding, decreased hospitalization rate, and reduced risk of pneumonia. Individuals aged 60 years and older, as well as those with underlying medical conditions, had a higher risk of developing pneumonia. What are the implication for public health practices?: Online surveys conducted through social media platforms have the potential to complement disease surveillance and data collection efforts. In terms of vaccination prioritization, it is recommended to prioritize older individuals and those with underlying diseases.

Employees' seeking preference towards influenza vaccination in organization: A discrete choice experiment in China.

To clarify the preferences of employees seeking influenza vaccination, a discrete choice experiment aims to understand the essential factors that close the gap between intention and behavior. A total of 866 employees with vaccination willingness willing to participated in a discrete choice experiment (DCE) between October 31st and December 6th, 2022 in China including the following attributes: price, vaccination setting, appointment mode, and service time. The data was analyzed using mixed logit models. Employees from smaller enterprises were more likely to get vaccinated collectively. For employees willing to get the influenza vaccine, 95.08 % of their choice was dominated by price. Employees' behavior varied according to their socioeconomic characteristics. Only female employees strongly favored work-site-based vaccination. Price was the primary factor considered by employees for getting the influenza vaccine. DCE would help to develop influenza vaccination intervention targeted at different groups in future studies.

Predicting influenza-like illness trends based on sentinel surveillance data in China from 2011 to 2019: A modelling and comparative study1.

Background: Influenza is an acute respiratory infectious disease with a significant global disease burden. Additionally, the coronavirus disease 2019 pandemic and its related non-pharmaceutical interventions (NPIs) have introduced uncertainty to the spread of influenza. However, comparative studies on the performance of innovative models and approaches used for influenza prediction are limited. Therefore, this study aimed to predict the trend of influenza-like illness (ILI) in settings with diverse climate characteristics in China based on sentinel surveillance data using three approaches and evaluate and compare their predictive performance. Methods: The generalized additive model (GAM), deep learning hybrid model based on Gate Recurrent Unit (GRU), and autoregressive moving average-generalized autoregressive conditional heteroscedasticity (ARMA-GARCH) model were established to predict the trends of ILI 1-, 2-, 3-, and 4-week-ahead in Beijing, Tianjin, Shanxi, Hubei, Chongqing, Guangdong, Hainan, and the Hong Kong Special Administrative Region in China, based on sentinel surveillance data from 2011 to 2019. Three relevant metrics, namely, Mean Absolute Percentage Error (MAPE), Root Mean Squared Error (RMSE), and R squared, were calculated to evaluate and compare the goodness of fit and robustness of the three models. Results: Considering the MAPE, RMSE, and R squared values, the ARMA-GARCH model performed best, while the GRU-based deep learning hybrid model exhibited moderate performance and GAM made predictions with the least accuracy in the eight settings in China. Additionally, the models' predictive performance declined as the weeks ahead increased. Furthermore, blocked cross-validation indicated that all models were robust to changes in data and had low risks of overfitting. Conclusions: Our study suggested that the ARMA-GARCH model exhibited the best accuracy in predicting ILI trends in China compared to the GAM and GRU-based deep learning hybrid model. Therefore, in the future, the ARMA-GARCH model may be used to predict ILI trends in public health practice across diverse climatic zones, thereby contributing to influenza control and prevention efforts.

Effectiveness of Multifaceted Strategies to Increase Influenza Vaccination Uptake: A Cluster Randomized Trial.

Importance: Influenza vaccination rates remain low among primary school students and vary by school in Beijing, China. Theory-informed, multifaceted strategies are needed to improve influenza vaccination uptake. Objective: To evaluate the effectiveness of multifaceted strategies in improving influenza vaccination uptake among primary school students. Design, Setting, and Participants: This cluster randomized trial was conducted from September 2022 to May 2023 across primary schools in Beijing, China. Schools were allocated randomly in a 1:1 ratio to multifaceted strategies or usual practice. Schools were deemed eligible if the vaccination rates in the 2019 to 2020 season fell at or below the district-wide average for primary schools. Eligible participants included students in grades 2 and 3 with no medical contraindications for influenza vaccination. Intervention: The multifaceted strategies intervention involved system-level planning and coordination (eg, developing an implementation blueprint, building social norms, and enhancing supervision), school-level training and educating school implementers (eg, conducting a 1-hour training and developing educational materials), and individual-level educating and reminding students and parents (eg, conducting educational activities and sending 4 reminders about vaccination). Main Outcomes and Measures: The primary outcomes were influenza vaccination uptake at school reported by school clinicians as well as overall vaccine uptake either at school or outside of school as reported by parents at 3 months. Generalized linear mixed models were used for analysis. Results: A total of 20 schools were randomized. One intervention school and 2 control schools did not administer vaccination on school grounds due to COVID-19, resulting in a total of 17 schools (9 intervention and 8 control). There was a total of 1691 students aged 7 to 8 years (890 male [52.6%]; 801 female [47.4%]) including 915 in the intervention group and 776 in the control group. Of all participants, 848 (50.1%) were in grade 2, and 1209 (71.5%) were vaccinated in the 2021 to 2022 season. Participants in the intervention and control groups shared similar characteristics. At follow-up, of the 915 students in the intervention group, 679 (74.5%) received a vaccination at school, and of the 776 students in the control group, 556 (71.7%) received a vaccination at school. The overall vaccination rates were 76.0% (695 of 915 students) for the intervention group and 71.3% (553 of 776 students) for the control group. Compared with the control group, there was significant improvement of vaccination uptake at school (odds ratio, 1.40; 95% CI, 1.06-1.85; P = .02) and overall uptake (odds ratio, 1.49; 95% CI, 1.12-1.99; P = .01) for the intervention group. Conclusions and Relevance: In this study, multifaceted strategies showed modest effectiveness in improving influenza vaccination uptake among primary school students, which provides a basis for the implementation of school-located vaccination programs of other vaccines in China, and in other countries with comparable programs. Trial registration: Chinese Clinical Trial Registry: ChiCTR2200062449.

Healthcare-seeking behaviours of patients with acute respiratory infection: a cross-sectional survey in a rural area of southwest China.

OBJECTIVES: This study aimed to assess the healthcare-seeking behaviour and related factors of people with acute respiratory symptoms in the rural areas of central and western China to estimate the disease burden of influenza more accurately. DESIGN: Cross-sectional survey. SETTINGS: Fifty-two communities/villages in the Wanzhou District, Chongqing, China, a rural area in southwest China, from May 2022 to July 2022. PARTICIPANTS: The participants were those who had been living in Wanzhou District continuously for more than 6 months and consented to participate. OUTCOME MEASURES: A semistructured questionnaire was used to determine the healthcare-seeking behaviour of participants, and the dichotomous response of 'yes' or 'no' was used to assess whether participants had acute respiratory symptoms and their healthcare-seeking behaviour. RESULTS: Only 50.92% (360 of 707) of the patients with acute respiratory infection visited medical and health institutions for treatment, whereas 49.08% (347 of 707) avoided treatment or opted for self-medication. The primary reason for not seeing a doctor was that patients felt their condition was not serious and visiting a medical facility for treatment was unnecessary. Short distance (87.54%) and reasonable charges (49.48%) were ranked as the most important reasons for choosing treatment at primary medical and health facilities (80.27%). The primary reasons for which patients visited secondary and tertiary hospitals (7.78% and 8.61%, respectively) were that doctors in such facilities were better at diagnosis (57.14%) and at treatment (87.10%). CONCLUSION: The findings provided in this study indicated that regular healthcare-seeking behaviour investigations should be conducted. The disease burden of influenza can be calculated more accurately when healthcare-seeking behaviour investigations are combined with surveillance in the hospitals.

Impact of innovative immunization strategy on PCV13 vaccination coverage among children under 5 years in Weifang city, China: A retrospective study.

BACKGROUND: Pneumococcal Diseases (PDs) remains a serious public health problem around the world and in China. Pneumococcal vaccination is the most cost-effective measure to prevent PDs. In 2021, the government of Weifang City, Shandong Province, China introduced a free dose of domestic 13-valent Pneumococcal Conjugate Vaccine (PCV 13) to vaccinate registered children aged 6 months-2 years. This study aimed to evaluate the vaccination rate of PCV13 in children aged under 5 years before and after the vaccination program to provide evidences for further improving the prevention and control strategy for PDs. METHODS: We collected data from the children's vaccination information management system in Weifang City and analyzed the PCV13 vaccination coverage and characteristics in all vaccination clinics of Weifang City for children aged under 5 years. We compared the differences in vaccination rates by gender, birth year, manufacturer, and county before and after innovative immunization strategy. RESULTS: Among the included 593,784 children aged under 5 years, the PCV13 vaccination rate in Weifang was generally low before the innovative immunization strategy. Urban children had a higher PCV13 coverage than rural children (P < 0.001), and parents tended to vaccinate their children with imported PCV13.The full vaccination rate for domestic and imported PCV13 was 0.67 % and 1.70 %, respectively. After the vaccination program, the PCV13 coverage of children increased significantly in all counties within Weifang City (P < 0.001), especially for children above 12 months of age. Most parents preferred to vaccinate their children with domestic PCV13, and the full vaccination rate of domestic and imported PCV13 was 6.59 % and 0.16 %, respectively. CONCLUSIONS: The vaccination rate of PCV13 in children is still much lower than the global average, posting a severe health challenge that needs to be addressed thoroughly. To improve the prevention and control strategy for PDs, it is recommended to continue to explore other relevant incentives based on the innovative immunization strategy. Furthermore, it is also recommended that China should incorporate PCV13 into the National Immunization Programs (NIP) as soon as possible.

13-Valent pneumococcal conjugate vaccines vaccination innovative strategy in Weifang City, China: a case study.

The World Health Organization (WHO) prioritizes pneumococcal disease as a vaccine-preventable disease and recommends the inclusion of pneumococcal conjugate vaccines (PCV) in national immunization programs worldwide. However, PCV is not included in the National Immunization Program in China and has low vaccination coverage due to its high cost. To address this, Weifang City implemented an innovative strategy for a 13-valent PCV (PCV13) on June 1, 2021. This strategy aimed to provide one dose of PCV13 free of charge for children aged 6 months to 2 years in registered households and to adopt a commercial insurance model with one dose of PCV13 free of charge in 2023 for children over 2 years old. The Health Commission of Weifang and other departments conducted a comprehensive investigation and considered various factors, such as vaccine effectiveness, safety, accessibility, vaccine price, and immunization schedules, for eligible children (under 5 years old). Stakeholder opinions were also solicited before implementing the policy. The Commission negotiated with various vaccine manufacturers to maximize its negotiating power and reduce vaccine prices. The implementation plan was introduced under the Healthy Weifang Strategy. Following the implementation of this strategy, the full course of vaccination coverage increased significantly from 0.67 to 6.59%. However, vaccination coverage is still lower than that in developed countries. Weifang's PCV13 vaccination innovative strategy is the first of its kind in Chinese mainland and is an active pilot of non-immunization program vaccination strategies. To further promote PCV13 vaccination, Weifang City should continue to implement this strategy and explore appropriate financing channels. Regions with higher levels of economic development can innovate the implementation of vaccine programs, broaden financing channels, improve accessibility to vaccination services, and advocate for more localities to incorporate PCV13 into locally expanded immunization programs or people-benefiting projects. A monitoring and evaluation system should also be established to evaluate implementation effects.