Evaluation of influenza vaccination coverage in Shanghai city during the 2016/17 to 2020/21 influenza seasons

Research trends and key contributors in studies on influenza vaccines for children: A 20-year bibliometric analysis

Globally, there are over 3 million severe cases of influenza each year, leading to up to half a million deaths. This study provides a comprehensive analysis of the current status of children's influenza vaccine research over the past 20 years and explores potential future research trends, including improvements in vaccine coverage and strategies to address vaccine hesitancy. We extracted all research data on children's influenza vaccines from 2004 to 2024 using the Web of Science Core Collection (WOSCC). The contributions of various countries/regions, institutions, authors, and journals in this field were assessed, and research hotspots as well as promising future trends were predicted through keyword analysis using CiteSpace and VOSviewer. A total of 2,598 related publications from 2004 to 2024 were identified and collected for analysis. The United States (USA) and England emerged as the leading contributors with the highest number of published papers. AstraZeneca was identified as a key leader among research institutions, and Ambrose Christopher S was recognized as the most productive author in this field. The journals Vaccine and Human Vaccines & Immunotherapeutics stood out as the most prominent publications in this area. The keyword analysis highlighted that international research collaboration maybe a promising strategy for bridging global gaps; Addressing vaccine hesitancy could potentially increase vaccination coverage; Live attenuated vaccines, intranasal administration and universal vaccines are promising directions for future development. These insights highlight potential avenues for improving influenza vaccine coverage and inform strategies to mitigate vaccine hesitancy, crucial for protecting children and enhancing public health.

Epidemiological analysis of influenza vaccination coverage in Pudong New Area, Shanghai (2013-2023): Implications for influenza vaccination strategies

Seasonal influenza remains a significant public health concern globally, with annual vaccinations as the most effectively preventive measure. This study examines influenza vaccination coverage rates across different age groups in Pudong New Area, Shanghai, China, from 2013 to 2023. This study extracted influenza vaccination data from the Shanghai Immunization Planning Information System (SIPIS) of the Center for Disease Control and Prevention Shanghai's Pudong New Area from 2013 to 2023. The analysis utilized weighted linear regression to compare vaccination rates over the study period. From 2013 to 2023, a cumulative total of 1,421,295 influenza vaccinations were administered in Pudong New Area, with the quadrivalent inactivated influenza vaccines (IIV4) and trivalent inactivated influenza vaccines (IIV3) comprising 56.8% and 42.9%, respectively. The overall average influenza vaccine coverage rate was 2.27% (95% CI: 2.26, 2.28). The 0-4 years group exhibited the highest average annual coverage rate of 22.52% (95% CI: 22.47, 22.57) among different age groups, in stark contrast to that of the 20-24 years age group, which had the lowest at 0.32% (95% CI: 0.31, 0.33). In terms of repeat vaccinations, a significant majority (86.87%) of recipients received only 1-2 doses, while just 13.13% received 3 or more doses. Although influenza vaccination coverage among preschool children in Pudong New Area is relatively high, it falls significantly short of WHO recommendations. Enhance the level of awareness of influenza vaccine among adults and provide a free influenza vaccination strategy for specific groups such as doctors, which is helpful to increase influenza vaccination rates among populations.

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.

Knowledge, Attitudes, and Practices towards Influenza Vaccine among Guangzhou Residents: A Cross-Sectional Study

BACKGROUND

Influenza vaccination is an important prevention strategy for flu illness. However, the vaccination rate is still low in Guangzhou, China. This study aimed to understand the status of knowledge, the attitude towards the vaccines' reliability and safety, and other aspects associated with the willingness and practice of influenza vaccines in the pediatric and adult populations of Guangzhou city.

METHODS

This study was performed in eleven districts in Guangzhou between November 2020 and December 2020, including the Yuexiu, Liwan, Haizhu, Tianhe, Baiyun, Panyu, Huadu, Nansha, Huangpu, Zengcheng, and Conghua districts. The parents of children and teenagers under the age of eighteen in Guangzhou were surveyed using self-administered questionnaires in four domains: demographic information, the knowledge status and perception of influenza vaccination, the willingness and attitude towards influenza vaccination, and previous vaccine uptake. A multivariable logistic regression was employed to assess the possible determinants of willingness and practice to receive influenza vaccination, calculating the odds ratios (ORs) and 95% confidence interval (CI). A two-sided p-value < 0.05 was deemed statistically significant.

RESULTS

A total of 13,213 valid questionnaires were collected (validity rate 98.8%). Out of these participants, 42.62% (5631 participants) expressed a willingness to receive the influenza vaccine, while 55.40% (7320 participants) reported that their children and teenagers had been vaccinated against the flu. Furthermore, 40.44% of the respondents (5343 participants) or other family members had received the influenza vaccine. Logistic regression indicated that factors such as being female (OR = 1.395, 95% CI: 1.278-1.522), being involved in the work of COVID-19 prevention and control (1.551, 1.396-1.724), affirming the preventive effects of vaccination (2.474, 2.106-2.906), knowing about annual influenza vaccination (2.756, 2.540-2.992), and understanding prioritized influenza vaccination populations (1.464, 1.343-1.596) were all positively associated with vaccination willingness. Conversely, middle-aged persons (aged 40-49 years old) (0.726, 0.617-0.853), higher educational levels (undergraduate versus middle school) (0.858, 0.768-0.959), heightened concerns about vaccine safety (considering side effects are obvious versus considering it is safe and basically no side effects) (0.284, 0.188-0.429) and lower knowledge scores (0.813, 0.701-0.942) were adversely linked with vaccination willingness.

CONCLUSION

These findings provide essential insights for altering the perception of influence and influenza vaccination, as well as enhancing health communication strategies to improve influenza vaccine uptake among Guangzhou residents.

Influenza Vaccination Coverage in Children: How Has COVID-19 Influenced It? A Review of Five Seasons (2018-2023) in Central Catalonia, Spain

Influenza vaccination is the main method of preventing influenza. Vaccination is recommended for certain individuals with diseases that could cause complications in the case of flu infection. The objective of this retrospective observational study was to examine influenza vaccination coverage in patients with risk factors, to describe the characteristics of those vaccinated and to study the influence of COVID-19. The study population was children under 14 years old with risk factors between 2018/19 and 2022/23 in Central Catalonia, sourced through the electronic database of the Catalan Institute of Health. The association of influenza vaccination data with sociodemographic data and risk factors was performed by bivariate and multivariate analysis. A total of 13,137 children were studied. Of those, 4623 had received the influenza vaccine in at least one season. The average influenza vaccination rate was 28.8%. The statistically significant factors associated with vaccination were age and having certain risk factors: asthma, diabetes, haemoglobinopathies and clotting disorders. In all seasons, the immigrant population was vaccinated more than the native population p < 0.05, except for the COVID-19 season (2020/21), where no differences were observed. Of those vaccinated, 7.1% had been vaccinated for 5 consecutive years. Influenza vaccination coverage in the paediatric age group was low. Vaccination promotion measures must be implemented. COVID-19 meant an increase in vaccination of the native population to the same level as that of the immigrant population.

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.

Effect of Primary Care Center Characteristics, Healthcare Worker Vaccination Status and Patient Economic Setting on Patient Influenza Vaccination Coverage Rates

BACKGROUND

Reaching the public health organizations targets of influenza vaccination in at-risk patient groups remains a challenge worldwide. Recognizing the relationship between the healthcare system characteristics and the economic environment of the population with vaccination uptake can be of great importance to improve.

METHODS

Several characteristics were correlated in this retrospective ecological study with data from 6.8 million citizens, 15,812 healthcare workers across 258 primary care health centers, and average income by area of the care center in Spain.

RESULTS

No correlation between HCW vaccination status and patient vaccination was found. A weak negative significant correlation between the size of the population the care center covers and their vaccination status did exist (6 mo.-59 yr., r = 0.19, p = 0.002; 60-64 yr., r = 0.23, p < 0.001; ≥65 yr., r = 0.23, p ≥ 0.001). The primary care centers with fewer HCWs had better uptake in the at-risk groups in the age groups of 60-64 yr. (r = 0.20, p = 0.002) and ≥65 (r = 0.023, p ≥ 0.001). A negative correlation was found regarding workload in the 6 mo.-59 yr. age group (r = 0.18, p = 0.004), which showed the at-risk groups that lived in the most economically deprived areas were more likely to be vaccinated.

CONCLUSIONS

This study reveals that the confounding variables that determine influenza vaccination in a population and in HCWs are complex. Future influenza campaigns should address these especially considering the possibility of combining influenza and SARS-CoV-2 vaccines each year.

Knowledge and Willingness toward Vaccination among Pregnant Women: Comparison between Pertussis and Influenza

BACKGROUND

Our study sought to characterize the knowledge and willingness levels regarding vaccinations against pertussis and seasonal influenza (influenza) among pregnant women in Guizhou province, China, which have previously been unclear.

METHODS

In total, 11 hospitals that carried out obstetrics and antenatal examination services were randomly included in the target organizations, and 564 questionnaires completed by the pregnant women were collected and analyzed in Guizhou province. The questionnaires contained questions addressing awareness and knowledge of pertussis and influenza, willingness to be vaccinated at different life stages, and the basic statuses of subjects. A two-paired McNemar test was used to compare the knowledge levels on pertussis and influenza. A Friedman test was used to compare the willingness to be vaccinated at different life stages. To explore the factors influencing knowledge levels, a chi-square test and binary logistic regression were used with stepwise backward regression.

RESULTS

In total, 11.9 percent of the pregnant women had received influenza vaccines in the year prior to their pregnancy in Guizhou province. The pregnant women had poorer knowledge of pertussis than of influenza. Given a vaccine was available, the willingness of pregnant women to partake in the following vaccination-related actions could be ranked, from highest to lowest: free vaccination of babies, recommend vaccination to family members, postpartum vaccination, vaccination of babies at mothers' expense, and vaccination during pregnancy. Knowledge levels played different roles in the women's willingness to receive vaccinations at different life stages. Common knowledge of pertussis and influenza played a limited role in the willingness to receive maternal vaccinations. Among the pregnant women, the factors influencing the low levels of pertussis knowledge were occupation as nonmedical-institution staff, lower educational level, pregnancy stage past the first trimester, and not bearing children; for influenza, the factors were occupation as nonmedical-institution staff, lower educational level, denial of pregnancy-induced disease, and lower monthly household income per capita.

CONCLUSIONS

Pregnant women have poorer levels of knowledge on pertussis than influenza, whereas there was no significant difference in their willingness to be vaccinated against these conditions. Health education on pertussis should be strengthened and we called for vaccines given at birth.

Influenza Vaccine Uptake in the United States before and during the COVID-19 Pandemic

The COVID-19 pandemic, along with disruptions to routine medical care, brought renewed urgency to public health messaging about the importance of influenza vaccination. This retrospective cohort study used a database of linked claims and electronic medical record data to evaluate clinical and demographic characteristics and influenza vaccination history associated with changes in influenza vaccine uptake following the start of the COVID-19 pandemic. Influenza vaccine uptake was examined in six seasons (2015−2016 through 2020−2021). Individuals were grouped by vaccination history in the five seasons before 2020−2021. Characteristics of 2020−2021 vaccinated vs. unvaccinated individuals were compared, stratified by vaccination history. Overall influenza vaccination uptake was highest in 2020−2021 (35.4%), following a trend of increasing uptake since 2016−2017 (31.4%). Uptake in 2020−2021 was observed in all age groups except ≥65 years, and the increase was particularly notable in individuals <18 years. In the previous five seasons, individuals ≤17 and >65 years, White, and Asian individuals were most likely, while 18-to-49-year-olds and those with fewer comorbidities were least likely, to be consistently vaccinated. Influenza vaccination status in 2020−2021 aligned with vaccination history; few differences in patient characteristics (age, comorbidities, state of residence) were observed when stratified by vaccination history.