Investigating Nonspecific Effects of the Live-Attenuated Japanese Encephalitis Vaccine on Lower Respiratory Tract Infections in Children Aged 25-35 Months: Retrospective Cohort Study.

BACKGROUND: Live attenuated vaccines may be used to prevent nontargeted diseases such as lower respiratory tract infections (LRTIs) due to their nonspecific effects (NSEs). OBJECTIVE: We aimed to analyze the NSEs of the Japanese encephalitis vaccine on pediatric LRTIs in children aged 25 months to 35 months. METHODS: A retrospective cohort study was conducted by using a population-based electronic health record database in Zhejiang, China. Enrolled participants were children born from January 1, 2017, to December 31, 2017, and who were inoculated with the live-attenuated Japanese encephalitis vaccine (JE-L) or inactivated Japanese encephalitis vaccine (JE-I) as the most recent vaccine at 24 months of age. The study was carried out between January 1, 2019, and December 31, 2019. All inpatient and outpatient hospital visits for LRTIs among children aged 25 months to 35 months were recorded. The Andersen-Gill model was used to assess the NSEs of JE-L against LRTIs in children and compared with those of JE-I as the most recent vaccine. RESULTS: A total of 810 children born in 2017 were enrolled, of whom 585 received JE-L (JE-L cohort) and 225 received JE-I (JE-I cohort) as their last vaccine. The JE-L cohort showed a reduced risk of LRTIs (adjusted hazard ratio [aHR] 0.537, 95% CI 0.416-0.693), including pneumonia (aHR 0.501, 95% CI 0.393-0.638) and acute bronchitis (aHR 0.525, 95% CI 0.396-0.698) at 25 months to 35 months of age. The NSEs provided by JE-L were especially pronounced in female children (aHR 0.305, 95% CI 0.198-0.469) and children without chronic diseases (aHR 0.553, 95% CI 0.420-0.729), without siblings (aHR 0.361, 95% CI 0.255-0.511), with more than 30 inpatient and outpatient hospital visits prior to 24 months of age (aHR 0.163, 95% CI 0.091-0.290), or with 5 to 10 inpatient and outpatient hospital visits due to infectious diseases prior to 24 months old (aHR 0.058, 95% CI 0.017-0.202). CONCLUSIONS: Compared with JE-I, receiving JE-L as the most recent vaccine was associated with lower risk of inpatient and outpatient hospital visits for LRTIs among children aged 25 months to 35 months. The nature of NSEs induced by JE-L should be considered for policymakers and physicians when recommending JE vaccines to those at high risk of infection from the Japanese encephalitis virus.

The 2nd China Vaccinology Integrated Innovation & Teaching Development Conference: Promoting the construction of vaccinology discipline system.

The 2nd China Vaccinology Integrated Innovation & Teaching Development Conference was held in Sun Yat-sen University, Shenzhen, 18-19, November 2023. Over 200 participants in the field of Vaccinology gathered together to address challenges and issues relevant to vaccine education and training courses, research, and public health programs in China. The conference themed "Promoting the Integrated and Innovative Development of Vaccinology through Collective Efforts." The conference was organized by the China Association of Vaccine (CAV) and hosted by Vaccinology Education Professional Committee of CAV, and School of Public Health (Shenzhen), Sun Yat-sen University. Other partners included the Medical Virology Branch of the Chinese Medical Association, the editorial committee of the Chinese Journal of Preventive Medicine, Human Vaccines & Immunotherapeutics, and the People's Medical Publishing House. The 1st conference was held in Hangzhou, in October 2020.

Gap between cognitions and behaviors among children's guardians of influenza vaccination: The role of social influence and vaccine-related knowledge.

The seasonal influenza vaccine coverage remains suboptimal among children even though guardians expressed high willingness to vaccinate their children. This study aimed to determine the association between vaccine hesitancy and uptake to facilitate vaccination; thus, bridging the gap. A cross-sectional design, using stratified cluster random sampling, was conducted among guardians of 0-59-month-old Chinese children from July to October in 2019. A structural equation model was applied to explore the interrelationships between factors including vaccine hesitancy, vaccination, social influence, and relative knowledge among guardians. Of the 1,404 guardians, 326 were highly hesitant to vaccinate their children, 33.13% (108/326) of whom had vaccinated their children. Moreover, 517 and 561 guardians had moderate and low vaccine hesitancy, with corresponding vaccine coverage of 42.75% (221/517) and 47.95% (269/516). Guardians' gender, age, and education level were demographic variables with significant moderating effects. Social influence considered impact of communities, family members, friends, neighbors, healthcare workers, bad vaccination experience and sense on price. Actual vaccine uptake was negatively significantly associated with hesitancy (ß = -0.11, p < .001) with positive association with social influence (ß = 0.61, p < .001). Vaccine hesitancy was negatively significantly associated with relative knowledge (ß = -2.14, p < .001) and social influence (ß = -1.09, p < .001). A gap is noted between cognitions and behaviors among children's guardians regarding influenza vaccination. A comprehensive strategy including emphasizing benefits of the influenza vaccination, risk of infection, and ensuring high vaccine confidence among healthcare workers can help transform the willingness to engage in the behavior of vaccination.

Stages of HPV Vaccine Hesitancy Among Guardians of Female Secondary School Students in China.

PURPOSE: Female secondary school students are the primary recommended population for human papillomavirus (HPV) vaccines. However, vaccine hesitancy may affect uptake. In this study, we assessed the vaccine hesitancy levels among the guardians of female secondary school students in China. METHODS: We developed a questionnaire and conducted cross-sectional surveys among guardians of secondary school girls aged 12-19 years in mainland China based on the Increasing Vaccination Model and the Precaution Adoption Process Model. RESULTS: We collected 3,225 valid samples. Among the participating guardians, 53.9% were vaccine hesitant, although only 0.9% had refused HPV vaccines. Some individual characteristics of guardians (e.g. sex, education/income level) were associated with understanding HPV vaccines. Better knowledge of HPV vaccines and communication with reliable sources of information were associated with vaccine nonhesitancy. Practical barriers such as vaccine shortage and busy schedules prevented nonhesitant guardians from vaccinating their children. DISCUSSION: A substantial proportion of the guardians surveyed were HPV vaccine hesitant. Promoting HPV knowledge and communication with reliable sources (e.g. clinical doctors) could help fight against vaccine hesitancy.

Efficacy, effectiveness, and safety of herpes zoster vaccine in the immunocompetent and immunocompromised subjects: A systematic review and network meta-analysis.

Objective: To investigate the efficacy, effectiveness and safety of recombinant zoster vaccine (RZV) and zoster vaccine live (ZVL) in immunocompetent and immunocompromised subjects. Methods: Data sources: PubMed, EMBASE, Cochrane Library, and Web of Science databases (up to Jan 2022) were searched to identify English articles. Search terms included randomized controlled trials (RCTs), observational studies, herpes zoster, RZV, ZVL. Study Selection: Only randomized controlled trials (RCTs) evaluating vaccine efficacy and safety and observational studies assessing vaccine effectiveness (after a vaccine was approved for marketing) were included. Data Extraction: Two researchers independently screened the literature, extracted the data, and checked the each other results. Results: Seventeen RCTs and 19 cohort studies were included. Among immunocompetent subjects, RZV was superior to ZVL at wide intervals (relative vaccine efficacy: 84%, 95% CI: 53%-95%; relative vaccine effectiveness: 49%, 95% CI: 21%-67%), across genders and subjects aged ≥ 60 years. Among immunocompromised subjects, RZV was superior to placebo in terms of vaccine efficacy (60%, 95% CI: 49%-69%). There was no difference between ZVL and placebo in those with selected immunosuppressive conditions. RZV was 45% (95% CI: 30%-59%) superior to ZVL in real-world practice. Compared with placebo, adverse events related to RZV were primarily related to injection-site and systemic, and RZV did not increase the risk of serious adverse events (SAEs) or death. There was no difference in the incidence of adverse events between groups with and without immunosuppression. Conclusions: Both RZV and ZVL can reduce the risk of herpes zoster in both immunocompetent and immunocompromised subjects. RZV was well-tolerated in the study population and demonstrated stronger protection than ZVL. Systematic review registration: Prospero CRD42022310495.

Effectiveness of interventions for human papillomavirus vaccine hesitancy among female university students based on the precaution adoption process model / 预防医学

Objective @#To evaluate the effectiveness of interventions for human papillomavirus ( HPV ) vaccine hesitancy among female university students based on the precaution adoption process model (PAPM), so as to provide the evidence for improving the coverage of HPV vaccine in this population. @*Methods @#HPV vaccine hesitant female students were selected using a cluster sampling method from Zhejiang Chinese Medical University, and randomly assigned to the PAPM group and control group. Students in the PAPM group received PAPM-based interventions for HPV vaccine hesitancy, while students in the control group were given routine interventions. The HPV-related knowledge, HPV vaccine-related knowledge and HPV vaccine hesitancy scores were collected from both groups prior to interventions ( T0 ), 0 ( T1 ), 1 ( T2 ) and 3 months post-interventions ( T3 ), and the effectiveness of interventions was evaluated using analysis of variance for repeated measures.@*Results @#There were 147 students in the PAPM group and 141 students in the control group. In the PAPM group, 36.73% of the students majored in medical sciences, and 48.23% were freshmen; in the control group, 39.72% majored in medical sciences, and 50.35% were freshmen. The mean scores of HPV- and HPV vaccine-related knowledge were significantly greater in the PAPM group than in the control group, respectively ( T1, 5.29 vs. 4.91; T2, 4.27 vs. 4.22; T3, 4.22 vs. 4.04; P<0.05 ); however, no significant differences were detected in the HPV vaccine hesitancy scores between the two groups, respectively ( T1, 2.98 vs. 2.95; T2, 3.07 vs. 3.07; T3, 3.08 vs. 2.97; P>0.05 ). The mean scores of the confidence dimension ( T1, 3.37 vs. 3.23; T2, 3.48 vs. 3.40; T3, 3.38 vs. 3.25 ) and the dimension of influence by others ( T1, 3.44 vs. 3.33; T2, 3.42 vs. 3.37; T3, 3.46 vs. 3.27 ) were significantly greater in the PAPM group than in the control group (P<0.05), while the mean scores of the complacency dimension were significantly lower in the PAPM group than in the control group ( T1, 1.98 vs. 2.03; T2, 2.06 vs. 2.20; T3, 2.18 vs. 2.15; P<0.05 ).@*Conclusions @#PAPM-based interventions for HPV vaccine hesitancy may effectively improve the awareness of HPV and HPV vaccines, reduce complacency, and enhance the influence by others among female university students.

Incidence and disease burden of community-acquired pneumonia in southeastern China: data from integrated medical resources.

Community-acquired pneumonia (CAP) is a lower respiratory tract infection. It is one of the commonest infectious diseases and the third leading cause of death worldwide. However, the epidemiological profiles of CAP in southeastern China are unknown. Data of inpatients and outpatients diagnosed with CAP from January 1, 2015 to December 31, 2020 were obtained from the National Healthcare Big Data in Fuzhou (Fuzhou Database). This database covers medical data from 37 hospitals and 159 community health service stations. The incidence rate, treatment pattern, and direct medical costs of CAP were assessed using clinical data. A total of 8,156,237 patients were enrolled, with a mean age of 33.72 ± 20.88 years. The overall incidence rate of CAP was 3.13 (95% confidence interval [CI]: 3.11-3.15) per 1000 person-years (PY), with 15.97 (95% CI: 15.85-16.08) per 1000 PY in children below 5 years old and 2.62 (95% CI: 2.57-2.66) per 1000 PY in the elderly ≥60 years. The cost per outpatient was $242.83 ± 341.62, and the cost per inpatient was $4,530.4 ± 9,151.68. The three most used therapeutic drugs in patients with CAP are cefotaxime, moxifloxacin, and azithromycin. In addition, despite the ability of both imported and domestic pneumococcal conjugate vaccines to reduce the incidence rate of CAP, the current vaccination coverage rates were relatively low. We suggest that more attention should be paid to the disease burden of CAP, especially due to its great economic burden in China.

Seasonal influenza vaccine hesitancy profiles and determinants among Chinese children's guardians and the elderly.

OBJECTIVES: Seasonal influenza vaccine coverage remains low in China due to possible influenza vaccine hesitancy (IVH) and practical issues. We sought to investigate IVH and its determinants among children's guardians and the elderly for a better understanding of the situation and for future intervention. METHODS: We performed two cross-sectional studies to identify the profiles and determinants of IVH using stratified cluster random sampling in an eastern China province in 2019. RESULTS: Of the 1564 guardians and 522 elders, 43.2% (95%CI: 40.4-46.0%) of guardians and 33.5% of elders (95%CI: 29.5-37.6%) had IVH. 'From rural area' (odds ratio: 1.36), 'don't know government recommendation for flu vaccination' (1.39), 'don't know flu vaccine is vaccinated annually' (1.93), and 'family members (0.22), friends and neighbors had positive attitude toward flu vaccine' (0.58) were related factors of the guardians' IVH. 'Aged 70-79 years' (0.46), 'had flu before' (0.35) and 'once had been vaccinated' (0.42) were related to the elderly's IVH. CONCLUSION: Poor awareness of influenza and vaccination, relatives' negative/positive attitude, lack of government recommendations, anxiety about vaccine quality, and practical issues such as short supply are related to IVH in China. Precision education aimed at hesitancy in wider groups is anticipated to increase vaccine confidence and coverage in influenza-vulnerable groups.

An online survey of the attitude and willingness of Chinese adults to receive COVID-19 vaccination.

Background: A safe and effective vaccine against COVID-19 has become a public health priority. However, little is known about the public willingness to accept a future COVID-19 vaccine in China. This study aimed to understand the willingness and determinants for the acceptance of a COVID-19 vaccine among Chinese adults.Methods: A cross-sectional survey using an online questionnaire was conducted in an adult population in China. Chi-square tests were used to identify differences for various intentions regarding COVID-19 vaccination. The t test was used to identify differences among vaccine hesitancy scores. Multivariable logistic regression was used to analyze the predicated factors associated with the willingness to receive a COVID-19 vaccine.Results: Of the 3195 eligible participants, 83.8% were willing to receive a COVID-19 vaccine, and 76.6% believed the vaccine would be beneficial to their health; however, 74.9% expressed concerns or a neutral attitude regarding its potential adverse effects. Of the participants, 76.5% preferred domestically manufactured vaccines and were more willing to be vaccinated than those who preferred imported vaccines. Multivariable logistic regression indicated that lack of confidence, complacency in regard to health, risk of the vaccine, and attention frequency were the main factors affecting the intention to receive a COVID-19 vaccine.Conclusion: Our study indicated that the respondents in China had a high willingness to accept a COVID-19 vaccine, but some participants also worried about its adverse effects. Information regarding the efficacy and safety of an upcoming COVID-19 vaccine should be disseminated to ensure its acceptance and coverage.

Incidence and disease burden of herpes zoster in the population aged ≥50 years in China: Data from an integrated health care network.

BACKGROUND: Herpes zoster (HZ) mainly affects elderly and immunocompromised individuals and is characterized by a painful vesicular rash. Data on the epidemiology of HZ, particularly in unvaccinated individuals aged ≥50 years, are still limited in China. Thus, this study aimed to evaluate the epidemiological features, disease burden, and associated risk factors of HZ in the population aged ≥50 years in China. METHODS: We evaluated HZ patients who were aged ≥50 years between January 1, 2015 and December 31, 2017 in the electronic health record database of Yinzhou district. HZ and its complications were identified using ICD-10 codes. In addition, post-herpetic neuralgia (PHN) as a complication of HZ was defined as pain occurring or persisting 90 days after rash onset. The disease burden was estimated according to the duration of hospitalization, frequency of visits, pharmacological treatment cost, and examination cost. Cox proportional hazards regression was used to investigate the associated risk factors for HZ. RESULTS: The overall incidence of HZ was 6.64 per 1000 person-years. Of the 4,313 initial episodes from 2015 to 2017, there were 99 recurrent cases. In total, 7.26% and 3.94% of the HZ patients had PHN and other complications, respectively. The average frequency of outpatient visits was significantly lower in patients with initial disease than that in patients with recurrence (3.6 vs. 6.7 per patient). The mean duration of hospital stay was longer in the recurrent episode than that in the initial episode (24.0 vs. 21.6 days). The inpatient and outpatient cost per new-onset HZ was approximately ¥8116.9 and ¥560.2 per patient, respectively. Age; female sex; suburban residency; and presence of immunocompromised disease, hypertension, or diabetes were significantly associated with the development of HZ. CONCLUSION: The incidence and recurrence rates of HZ showed different trends with increasing age. The presence of HZ-related complications increased the direct medical costs. Our findings help provide a basis for developing appropriate strategies for HZ prevention and control.

Dose effect of influenza vaccine on protection against laboratory-confirmed influenza illness among children aged 6 months to 8 years of age in southern China, 2013/14-2015/16 seasons: a matched case-control study.

Background We conducted a matched case-control study in China during the 2013/14-2015/16 influenza seasons to estimate influenza vaccine effectiveness (VE) by dose among children aged 6 months to 8 years.Methods Cases were laboratory-confirmed influenza infections identified through the influenza-like illness sentinel surveillance network in Guangzhou. Age- and sex-matched community controls were randomly selected through the expanded immunization program database. We defined priming as receipt of ≥1 dose of influenza vaccine during the immediate prior season.Results In total, 4,185 case-control pairs were analyzed. Among children 6-35 months, VE for current season dose(s) across the three seasons during 2013/14-2015/16 were 59% (95% Confidence Interval: 44-71%), 12% (-11%,30%), 54% (32-69%); among unprimed children 6-35 months, VE for 1 vs 2 current season doses were 45% (8-67%) vs 65% (46-78%), -2% (-53%,32%) vs 19% (-11%,40%), and 37% (-24%,68%) vs 61% (32-78%). Among children aged 3-8 years, VE for current season dose(s) across study seasons were 62% (36-78%), 43% (22-58%), 32% (1-53%). VE for unprimed children receiving 1 dose only in current season was insignificant or lower than among all children.Conclusion Findings support utility of providing second dose ("booster dose") of seasonal influenza vaccine to unprimed children aged 6-35 months, and the need to study further dose effect of a booster dose among unprimed children aged 3-8 years in China.

Epidemiological characteristics and associated factors of delayed voiding among middle school students / 中国学校卫生

Objective@#To analyze the epidemiological characteristics and associated factors of delayed voiding among middle school students, and to provide the basis for health education.@*Methods@#A total of 1 260 middle school students were selected from Sanmen country in Taizhou by using multi-stage stratified sampling method. A cross-sectional survey was conducted to investigate the demographic characteristics, epidemiological characteristics and associated factors of delayed voiding by questionnaire.@*Results@#The proportion of frequent delayed voiding among middle school students was 14.37%(181). The proportion among senior high school students was 15.51%(90), and among junior high school students was 13.67%(91)，no significant differences were found by grade(χ2=0.57, P=0.45). The multivariate Logistic regression analysis showed that residential school, homework per day >2 hours, games and reduce the frequency of drinking ≥7 times/week were risk factors for delayed voiding frequently in junior high school students(OR=3.71, 1.70, 3.02,6.52，P<0.05). Higher than 2 hours of daily homework, a supportive or indifferent attitude to delayed voiding, staying in bed after waking up, drinking <0.5 L/d or ≥2.0 L/d, and reduce the frequency of drinking ≥7 times/week were risk factors for delayed voiding behavior in high school students(OR=2.23, 1.81, 2.22, 3.48, 2.69, 3.00, P<0.05).@*Conclusion@#The prevalence of frequent delayed voiding was high among middle school students. Attitude, environment and the quality of drinking water were the primary factors of frequent delayed voiding.

Prenatal exposure to perfluoroalkyl substances is associated with lower hand, foot and mouth disease viruses antibody response in infancy: Findings from the Guangzhou Birth Cohort Study.

BACKGROUND: Perfluoroalkyl substances (PFASs) are synthetic chemicals widely used in industry and for commercial products. Their immunomodulatory effects are a growing health concern in children. Hand, Foot and Mouth Disease (HFMD) is a common childhood viral infection, and increased incidence of which has parallel the rise in PFAS exposure in the Asia-Pacific region. OBJECTIVE: We conducted the first study to assess whether prenatal exposure to PFAS was associated with a reduction in HFMD virus antibodies in infants. METHODS: We enrolled 201 mother-infant pairs from the Guangzhou Birth Cohort Study from July to October 2013. High performance liquid chromatography-mass spectrometry was employed to determine concentrations of specific PFAS isomers in cord blood. Neutralizing antibodies titers were measured against two HFMD viruses, enterovirus 71 (EV71) and coxsackievirus A 16 (CA16), in cord blood serum and blood serum at three months of age. RESULTS: Higher umbilical cord blood PFAS concentrations were associated with lower EV71 and CA16 antibody concentrations. A doubling in the composite sum of cord blood PFASs in three month old infants was associated with significant increase in the risk of HFMD antibody concentration below clinical protection level (≥1:8 titers) for CA16 (odds ratio, OR: 2.74 [95% confidence interval (CI): 1.33, 5.61] and for EV71 (OR = 4.55, 95% CI: 1.45, 4.28). This association was higher in boys at three months of age for CA16. CONCLUSIONS: Our findings suggest that cord blood PFAS exposure is associated with lower HFMD antibody in infancy. Given the widespread nature of PFAS exposures and the high global incidence of HFMD globally, these findings have substantial public health implications and therefore, these associations need to be replicated in a larger study to more definitively address the risk.

Rotavirus Gastroenteritis Infection Among Children Vaccinated and Unvaccinated With Rotavirus Vaccine in Southern China: A Population-Based Assessment.

Importance: Since 2000, the Lanzhou lamb rotavirus vaccine has been exclusively licensed in China for voluntary rotavirus gastroenteritis (RV-GE) prevention. Objective: To evaluate the association of the Lanzhou lamb rotavirus vaccination with RV-GE among children in southern China. Design, Setting, and Participants: This cross-sectional, ecological study was set in Guangzhou, China. Participants were infants possibly vaccinated (aged 2 months to 3 years) and the children ineligible for vaccination (aged ≥4 years). The study was conducted from May 1, 2007, to April 30, 2016, and the data analysis was conducted in July 2016. Main Outcomes and Measures: Annual median age at onset of RV-GE and seasonal distribution of incidence. Cases of RV-GE in Guangzhou, China, diagnosed from May 1, 2007, to April 30, 2016, and reported to the National Information System for Disease Control and Prevention were examined. Poisson regression models were fitted among 32 452 children younger than 4 years and among 450 children who had been ineligible for vaccination, while controlling for secular trends, socioeconomic status, and meteorological factors. Logistic regression was used to assess the indirect effects provided by the vaccinated infants from 2009 to 2011 on unvaccinated infants aged 2 to 35 months based on a separate case-control data set. Results: During 9 seasons, 119 705 patients with gastroenteritis were reported; 33 407 were confirmed for RV-GE (21 202 [63.5%] male, 32 022 [95.8%] aged <4 years, and 31 306 [93.8%] residing in urban districts). The median age at onset for all patients with RV-GE increased from 11 months during the 2007 season to 15 months during the 2015 season, and the onset, peak, and cessation of incidence were delayed. When citywide vaccination coverage in the prior 12 months was classified into high and low groups (≥8.36% vs <8.36%), the incidence rate ratio for the high coverage group decreased by 32.4% among children younger than 4 years (incidence rate ratio, 0.676; 95% CI, 0.659-0.693; P < .001). Among the children ineligible for vaccination, the incidence rate ratio in higher coverage periods was 0.790 (95% CI, 0.351-0.915; P < .001) compared with the lower coverage. Compared with districts with 14% or less vaccination coverage, the adjusted odds ratio for RV-GE among unvaccinated children younger than 3 years was 0.85 (95% CI, 0.73-0.99; P = .03) for districts with 15% to 19% of coverage, and 0.79 (95% CI, 0.67-0.93; P = .004) for districts with more than 20% of coverage. Conclusions and Relevance: This study provides evidence of the population health benefits of the Lanzhou lamb rotavirus vaccination in preventing RV-GE among children in China younger than 4 years, including herd effects.

Ambient Air Pollution and Risk for Ischemic Stroke: A Short-Term Exposure Assessment in South China.

Data on the association between air pollution and risk of ischemic stroke in China are still limited. This study aimed to investigate the association between short-term exposure to ambient air pollution and risk of ischemic strokes in Guangzhou, the most densely-populated city in south China, using a large-scale multicenter database of stroke hospital admissions. Daily counts of ischemic stroke admissions over the study years 2013-2015 were obtained from the Guangzhou Cardiovascular and Cerebrovascular Disease Event Surveillance System. Daily particulate matter <2.5 µm in diameter (PM2.5), sulfur dioxide (SO2), nitrogen dioxide (NO2), ozone (O3), and meteorological data were collected. The associations between air pollutants and hospital admissions for stroke were examined using relative risks (RRs) and their corresponding 95% confidence intervals (CIs) based on time-series Poisson regression models, adjusting for temperature, public holiday, day of week, and temporal trends in stroke. Ischemic stroke admissions increased from 27,532 to 35,279 through 2013 to 2015, increasing by 28.14%. Parameter estimates for NO2 exposure were robust regardless of the model used. The association between same-day NO2 (RR = 1.0509, 95% CI: 1.0353-1.0668) exposure and stroke risk was significant when accounting for other air pollutants, day of the week, public holidays, temperature, and temporal trends in stroke events. Overall, we observed a borderline significant association between NO2 exposure modeled as an averaged lag effect and ischemic stroke risk. This study provides data on air pollution exposures and stroke risk, and contributes to better planning of clinical services and emergency contingency response for stroke.