Assessing vaccine literacy and exploring its association with vaccine hesitancy: A validation of the vaccine literacy scale in China.

BACKGROUND: Assessment of vaccine literacy is essential for understanding people's ability to access various vaccine information to meet health demands. Few studies have examined the role of vaccine literacy in vaccine hesitancy, which is a psychological state. This study aimed to validate the applicability of the HLVa-IT (Vaccine Health Literacy of Adults in Italian) scale in Chinese settings and to explore the association between vaccine literacy and vaccine hesitancy. METHODS: From May to June 2022, we conducted an online cross-sectional survey in mainland China. Potential factor domains were obtained by the exploratory factor analysis. Cronbach's alpha coefficient, composite reliability values, and square root values of average variances extracted were calculated to determine the internal consistency and discriminant validity. The association between vaccine literacy, vaccine acceptance, with vaccine hesitancy was assessed using logistic regression analysis. RESULTS: Totally, 12,586 participants completed the survey. Two potential dimensions, the functional and the interactive/critical, were identified. Cronbach's alpha coefficient and composite reliability values were >0.90. The square root values of average variances extracted exceeded the related correlations. The functional dimension (adjusted odds ratio (aOR): 0579; 95 % Confidence Interval (CI); 0.529, 0.635), interactive (aOR: 0.654; 95%CI: 0.531, 0.806)/critical (aOR: 0.709; 95%CI: 0.575, 0.873) dimension were significantly and negatively associated with vaccine hesitancy. Similar results were also found in different vaccines acceptance subgroups. LIMITATIONS: This report is limited by the convenience sampling method. CONCLUSIONS: The modified HLVa-IT is suitable for use in Chinese settings. Vaccine literacy was negatively associated with vaccine hesitancy.

Understanding Drivers of Vaccine Hesitancy During the COVID-19 Pandemic Among Older Adults in Jiangsu Province, China: Cross-sectional Survey.

BACKGROUND: Older adults are particularly at risk from infectious diseases, including serve complications, hospitalization, and death. OBJECTIVE: This study aimed to explore the drivers of vaccine hesitancy among older adults based on the "3Cs" (confidence, complacency, and convenience) framework, where socioeconomic status and vaccination history played the role of moderators. METHODS: A cross-sectional questionnaire survey was conducted in Jiangsu Province, China, between June 1 and July 20, 2021. Older adults (aged ≥60 years) were recruited using a stratified sampling method. Vaccine hesitancy was influenced by the 3Cs in the model. Socioeconomic status and vaccination history processed through the item parceling method were used to moderate associations between the 3Cs and hesitancy. Hierarchical regression analyses and structural equation modeling were used to test the validity of the new framework. We performed 5000 trials of bootstrapping to calculate the 95% CI of the pathway's coefficients. RESULTS: A total of 1341 older adults participated. The mean age was 71.3 (SD 5.4) years, and 44.7% (599/1341) of participants were men. Confidence (b=0.967; 95% CI 0.759-1.201; P=.002), convenience (b=0.458; 95% CI 0.333-0.590; P=.002), and less complacency (b=0.301; 95% CI 0.187-0.408; P=.002) were positively associated with less vaccine hesitancy. Socioeconomic status weakened the positive effect of low complacency (b=-0.065; P=.03) on low vaccine hesitancy. COVID-19 vaccination history negatively moderated the positive association between confidence (b=-0.071; P=.02) and lower vaccine hesitancy. CONCLUSIONS: Our study identified that confidence was the more influential dimension in reducing vaccine hesitancy among older adults. COVID-19 vaccination history, as well as confidence, had a positive association with less vaccine hesitancy and could weaken the role of confidence in vaccine hesitancy. Socioeconomic status had a substitution relationship with less complacency, which suggested a competitive positive association between them on less vaccine hesitancy.

Vaccination Intention and Behavior of the General Public in China: Cross-sectional Survey and Moderated Mediation Model Analysis.

BACKGROUND: Promoting vaccination and eliminating vaccine hesitancy are key measures for controlling vaccine-preventable diseases. OBJECTIVE: We aimed to understand the beliefs surrounding and drivers of vaccination behavior, and their relationships with and influence on vaccination intention and practices. METHODS: We conducted a web-based survey in 31 provinces in mainland China from May 24, 2021 to June 15, 2021, with questions pertaining to vaccination in 5 dimensions: attitude, subjective norms, perceived behavioral control, intention, and behavior. We performed hierarchical regression analysis and structural equation modeling based on the theory of planned behavior-in which, the variables attitude, subjective norms, and intention each affect the variable intention; the variable intention mediates the relationships of attitude and subjective norms with behavior, and the variable perceived behavioral control moderates the strength of this mediation-to test the validity of the theoretical framework. RESULTS: A total of 9924 participants, aged 18 to 59 years, were included in this study. Vaccination intention mediated the relationships of attitude and subjective norms with vaccination behavior. The indirect effect of attitude on vaccination behavior was 0.164 and that of subjective norms was 0.255, and the difference was statistically significant (P<.001). The moderated mediation analysis further indicated that perceived behavioral control would affect the mediation when used as moderator, and the interaction terms for attitude (ß=-0.052, P<.001) and subjective norms (ß=-0.028, P=.006) with perceived behavioral control were significant. CONCLUSIONS: Subjective norms have stronger positive influences on vaccination practices than attitudes. Perceived behavioral control, as a moderator, has a substitution relationship with attitudes and subjective norms and weakens their positive effects on vaccination behavior.

Changes in Parental Attitudes Toward COVID-19 Vaccination and Routine Childhood Vaccination During the COVID-19 Pandemic: Repeated Cross-sectional Survey Study.

BACKGROUND: It was reported that one in four parents were hesitant about vaccinating their children in China. Previous studies have revealed a declining trend in the vaccine willingness rate in China. There is a need to monitor the level of parental vaccine hesitancy toward routine childhood vaccination and hesitancy toward the COVID-19 vaccine during the ongoing COVID-19 pandemic. OBJECTIVE: This study aims to assess changes in trends of parental attitudes toward routine childhood vaccines and COVID-19 vaccinations across different time periods in China. METHODS: Three waves of cross-sectional surveys were conducted on parents residing in Wuxi City in Jiangsu Province, China from September to October 2020, February to March 2021, and May to June 2021. Participants were recruited from immunization clinics. Chi-square tests were used to compare the results of the three surveys, controlling for sociodemographic factors. Binary and multivariable logistic regression analysis was used to examine factors related to parental vaccine hesitancy and COVID-19 vaccine willingness. RESULTS: Overall, 2881, 1038, and 1183 participants were included in the survey's three waves. Using the Vaccine Hesitancy Scale, 7.8% (225/2881), 15.1% (157/1038), and 5.5% (65/1183) of parents showed hesitancy to childhood vaccination (P<.001), and 59.3% (1709/2881), 64.6% (671/1038), and 92% (1088/1183) of parents agreed to receive a COVID-19 vaccine themselves in the first, second, and third surveys, respectively (P<.001). In all three surveys, "concerns about vaccine safety and side effects" was the most common reason for refusal. CONCLUSIONS: There has been an increasing acceptance of COVID-19 vaccination in Wuxi City, China. Effective interventions are needed to mitigate public concerns about vaccine safety.

Transmissibility and pathogenicity of the severe acute respiratory syndrome coronavirus 2: A systematic review and meta-analysis of secondary attack rate and asymptomatic infection.

BACKGROUND: Understanding the transmissibility and pathogenicity of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is crucial for control policies, but evidence remains limited. METHODS: We presented a systematic and meta-analytic summary concerning the transmissibility and pathogenicity of COVID-19. RESULTS: A total of 105 studies were identified, with 35042 infected cases and 897912 close contacts. 48.6% (51/105) of studies on secondary transmissions were from China. We estimated a total SIR of 7.8% (95% confidence interval [CI], 6.8%-8.8%), SAR of 6.6% (95% CI, 5.7%-7.5%), and symptomatic infection ratio of 86.9% (95%CI, 83.9%-89.9%) with a disease series interval of 5.84 (95%CI, 4.92-6.94) days. Household contacts had a higher risk of both symptomatic and asymptomatic infection, and transmission was driven between index cases and second-generation cases, with little transmission occurring in second-to-later-generation cases (SIR, 12.4% vs. 3.6%). The symptomatic infection ratio was not significantly different in terms of infection time, generation, type of contact, and index cases. CONCLUSIONS: Our results suggest a higher risk of infection among household contacts. Transmissibility decreased with generations during the intervention. Pathogenicity of SARS-CoV-2 varied among territories, but didn't change over time. Strict isolation and medical observation measures should be implemented.

Using an extended protection motivation theory to explain vaccine hesitancy: a cross-sectional study among Chinese adults.

BACKGROUND: Vaccine hesitancy was listed as one of the top 10 issues threatening global health in 2019. The objectives of this study were to (a) use an extended protection motivation theory (PMT) with an added trust component to identify predictors of vaccine hesitancy and (b) explore the predictive ability of vaccine hesitancy on vaccination behavior. METHODS: We conducted an online questionnaire from February 9 to April 9, 2021, in China. The target population was Chinese residents aged 18 and over. A total of 14,236 responses were received. Structural equation modeling was used to test the extended PMT model hypotheses. RESULTS: A total of 10,379 participants were finally included in this study, of whom 52.0% showed hesitancy toward vaccination. 2854 (27.5%) participants reported that they got flu shots in the past year, and 2561 (24.7%) participants were vaccinated against COVID-19. 2857 (27.5%) participants engaged in healthcare occupation. The model explained 85.7% variance of vaccine hesitancy. Self-efficacy was the strongest predictor, negatively associated with vaccine hesitancy (ß = -0.584; p < .001). Response efficacy had a negative effect on vaccine hesitancy (ß = -0.372; p < .001), while threat appraisal showed a positive effect (ß = 0.104; p < .001). Compared with non-health workers, health workers showed more vaccine hesitancy, and response efficacy was the strongest predictor (ß = -0.560; p < .001). Vaccine hesitancy had a negative effect on vaccination behavior (ß = -0.483; p < .001), and the model explained 23.4% variance of vaccination behavior. CONCLUSIONS: This study demonstrates that the extended PMT model is efficient in explaining vaccine hesitancy. However, the predictive ability of vaccine hesitancy on vaccination behavior is limited.

Cost-Effectiveness of Public Health Measures to Control COVID-19 in China: A Microsimulation Modeling Study.

This study aimed to assess the cost-effectiveness of various public health measures in dealing with coronavirus disease 2019 (COVID-19) in China. A stochastic agent-based model was used to simulate the progress of the COVID-19 outbreak in scenario I (imported one case) and scenario II (imported four cases) with a series of public health measures. The main outcomes included the avoided infections and incremental cost-effectiveness ratios (ICERs). Sensitivity analyses were performed to assess uncertainty. The results indicated that isolation-and-quarantine averted the COVID-19 outbreak at the lowest ICERs. The joint strategy of personal protection and isolation-and-quarantine averted one more case than only isolation-and-quarantine with additional costs. The effectiveness of isolation-and-quarantine decreased with lowering quarantine probability and increasing delay time. The strategy that included community containment would be cost-effective when the number of imported cases was >65, or the delay time of the quarantine was more than 5 days, or the quarantine probability was below 25%, based on current assumptions. In conclusion, isolation-and-quarantine was the most cost-effective intervention. However, personal protection combined with isolation-and-quarantine was the optimal strategy for averting more cases. The community containment could be more cost-effective as the efficiency of isolation-and-quarantine drops and the imported cases increases.

Delays in routine childhood vaccinations and their relationship with parental vaccine hesitancy: a cross-sectional study in Wuxi, China.

OBJECTIVES: This study aimed to examine childhood vaccination delay, explore the association between vaccination delay and parental vaccine hesitancy, and assess childhood vaccination delays during the coronavirus disease (COVID)-19 pandemic in China. METHODS: This cross-sectional survey was conducted in Wuxi City. Participants were recruited from local vaccination clinics. Questionnaires were used to collect information about socio-demographics, vaccine hesitancy, and immunization clinic evaluations. Vaccination records were obtained from the Jiangsu Information Management System of Vaccination Cases. RESULTS: Overall, 2728 participants were included. The coverage for seven category A vaccines (Expanded Program on Immunization (EPI)) was more than 95% at 24 months. The proportion of children vaccinated in a timely manner was the highest for the first dose of the hepatitis B vaccine (91.6%) and the lowest for the Bacillus-Calmette-Guerin vaccine (44.6%). More than 50% of the planned vaccinations were delayed in February and March 2020. The Vaccine Hesitancy Scale scores were not associated with vaccination delay (P = 0.842). Children's vaccination delays were negatively associated with parents who reported convenient access to clinics and satisfaction with immunization services (P = 0.020, P = 0.045). CONCLUSIONS: EPI is highly successful in China. Despite vaccination delays due to the COVID-19 pandemic, coverage was recovered after lockdown restrictions were eased.

Reporting of coronavirus disease 2019 prognostic models: the transparent reporting of a multivariable prediction model for individual prognosis or diagnosis statement.

Evaluation of the validity and applicability of published prognostic prediction models for coronavirus disease 2019 (COVID-19) is essential, because determining the patients' prognosis at an early stage may reduce mortality. This study was aimed to utilize the transparent reporting of a multivariable prediction model for individual prognosis or diagnosis (TRIPOD) to report the completeness of COVID-19-related prognostic models and appraise its effectiveness in clinical practice. A systematic search of the Web of Science and PubMed was performed for studies published until August 11, 2020. All models were assessed on model development, external validation of existing models, incremental values, and development and validation of the same model. TRIPOD was used to assess the completeness of included models, and the completeness of each item was also reported. In total, 52 publications were included, including 67 models. Age, disease history, lymphoma count, history of hypertension and cardiovascular disease, C-reactive protein, lactate dehydrogenase, white blood cell count, and platelet count were the commonly used predictors. The predicted outcome was death, development of severe or critical state, survival time, and length-of-hospital stay. The reported discrimination performance of all models ranged from 0.361 to 0.994, while few models reported calibration. Overall, the reporting completeness based on TRIPOD was between 31% and 83% [median, 67% (interquartile range: 62%, 73%)]. Blinding of the outcome to be predicted or predictors were poorly reported. Additionally, there was little description on the handling of missing data. This assessment indicated a poorly-reported COVID-19 prognostic model in existing literature. The risk of over-fitting may exist with these models. The reporting of calibration and external validation should be given more attention in future research.

Epidemiology of 631 Cases of COVID-19 Identified in Jiangsu Province Between January 1st and March 20th 2020: Factors Associated with Disease Severity and Analysis of Zero Mortality.

BACKGROUND This retrospective study aimed to investigate the factors associated with disease severity and patient outcomes in 631 patients with COVID-19 who were reported to the Jiangsu Commission of Health between January 1 and March 20, 2020. MATERIAL AND METHODS We conducted an epidemiological investigation enrolling 631 patients with laboratory-confirmed COVID-19 from our clinic from January to March 2020. Patients' information was collected through a standard questionnaire. Then, we described the patients' epidemiological characteristics, analyzed risk factors associated with disease severity, and assessed causes of zero mortality. Additionally, some key technologies for epidemic prevention and control were identified. RESULTS Of the 631 patients, 8.46% (n=53) were severe cases, and no deaths were recorded (n=0). The epidemic of COVID-19 has gone through 4 stages: a sporadic phase, an exponential growth phase, a peak plateau phase, and a declining phase. The proportion of severe cases was significantly different among the 4 stages and 13 municipal prefectures (P<0.001). Factors including age >65 years old, underlying medical conditions, highest fever >39.0°C, dyspnea, and lymphocytopenia (<1.0×109/L) were early warning signs of disease severity (P<0.05). In contrast, earlier clinic visits were associated with better patient outcomes (P=0.029). Further, the viral load was a potentially useful marker associated with COVID-19 infection severity. CONCLUSIONS The study findings from the beginning of the COVID-19 epidemic in Jiangsu Province, China showed that patients who were more than 65 years of age and with comorbidities and presented with a fever of more than 39.0°C developed more severe disease. However, mortality was prevented in this initial patient population by early supportive clinical management.

Epidemiologic characteristics and influencing factors of cluster infection of COVID-19 in Jiangsu Province.

To understand the characteristics and influencing factors related to cluster infections in Jiangsu Province, China, we investigated case reports to explore transmission dynamics and influencing factors of scales of cluster infection. The effectiveness of interventions was assessed by changes in the time-dependent reproductive number (Rt). From 25th January to 29th February, Jiangsu Province reported a total of 134 clusters involving 617 cases. Household clusters accounted for 79.85% of the total. The time interval from onset to report of index cases was 8 days, which was longer than that of secondary cases (4 days) (χ2 = 22.763, P < 0.001) and had a relationship with the number of secondary cases (the correlation coefficient (r) = 0.193, P = 0.040). The average interval from onset to report was different between family cluster cases (4 days) and community cluster cases (7 days) (χ2 = 28.072, P < 0.001). The average time interval from onset to isolation of patients with secondary infection (5 days) was longer than that of patients without secondary infection (3 days) (F = 9.761, P = 0.002). Asymptomatic patients and non-familial clusters had impacts on the size of the clusters. The average reduction in the Rt value in family clusters (26.00%, 0.26 ± 0.22) was lower than that in other clusters (37.00%, 0.37 ± 0.26) (F = 4.400, P = 0.039). Early detection of asymptomatic patients and early reports of non-family clusters can effectively weaken cluster infections.

Chinese Residents' Perceptions of COVID-19 During the Pandemic: Online Cross-sectional Survey Study.

BACKGROUND: COVID-19 has posed a global threat due to substantial morbidity and mortality, and health education strategies need to be adjusted accordingly to prevent a possible epidemic rebound. OBJECTIVE: This study aimed to evaluate the perceptions of COVID-19 among individuals coming to, returning to, or living in Jiangsu Province, China, and determine the impact of the pandemic on the perceptions of the public. METHODS: In this study, an online questionnaire was distributed to participants between February 15 and April 21, 2020. The questionnaire comprised items on personal information (eg, sex, age, educational level, and occupation); protection knowledge, skills, and behaviors related to COVID-19; access to COVID-19-related information; and current information needs. Factors influencing the knowledge score, skill score, behavior score, and total score for COVID-19 were evaluated using univariate and multivariate analyses. The time-varying reproduction number (Rt) and its 95% credible interval were calculated and compared with the daily participation number and protection scores. RESULTS: In total, 52,066 participants were included in the study; their average knowledge score, skill score, behavior score, and total score were 25.58 (SD 4.22), 24.05 (SD 4.02), 31.51 (SD 2.84), and 90.02 (SD 8.87), respectively, and 65.91% (34,315/52,066) had a total protection score above 90 points. For the knowledge and skill sections, correct rates of answers to questions on medical observation days, infectiousness of asymptomatic individuals, cough or sneeze treatment, and precautions were higher than 95%, while those of questions on initial symptoms (32,286/52,066, 62.01%), transmission routes (37,134/52,066, 71.32%), selection of disinfection products (37,390/52,066, 71.81%), and measures of home quarantine (40,037/52,066, 76.90%) were relatively low. For the actual behavior section, 97.93% (50,989/52,066) of participants could wear masks properly when going out. However, 19.76% (10,290/52,066) could not disinfect their homes each week, and 18.42% (9589/52,066) could not distinguish differences in initial symptoms between the common cold and COVID-19. The regression analyses showed that the knowledge score, skill score, behavior score, and total score were influenced by sex, age, educational level, occupation, and place of residence at different degrees (P<.001). The government, television shows, and news outlets were the main sources of protection knowledge, and the information released by the government and authoritative medical experts was considered the most reliable. The current information needs included the latest epidemic developments, disease treatment progress, and daily protection knowledge. The Rt in the Jiangsu Province and mainland China dropped below 1, while the global Rt remained at around 1. The maximal information coefficients ranged from 0.76 to 1.00, which indicated that the public's perceptions were significantly associated with the epidemic. CONCLUSIONS: A high proportion of the participants had sufficient COVID-19 protection knowledge and skills and were able to avoid risky behaviors. Thus, it is necessary to apply different health education measures tailored to work and study resumption for specific populations to improve their self-protection and, ultimately, to prevent a possible rebound of COVID-19.

COVID-19 outbreak following a single patient exposure at an entertainment site: An epidemiological study.

We investigated an outbreak of COVID-19 infection, which was traced back to a bathing pool at an entertainment venue, to explore the epidemiology of the outbreak, understand the transmissibility of the virus and analyse the influencing factors. Contact investigation and management were conducted to identify potential cases. Epidemiological investigation was carried out to determine the epidemiological and demographic characteristics of the outbreak. We estimated the secondary attack rate (SAR), incubation time and time-dependent reproductive number (Rt ) and explored the predisposing factors for cluster infection. The incubation time was 5.4 days and the serial interval (SI) was 4.4 days, with the rate of negative-valued SIs at 24.5%. The SAR at the bathing pool (3.3%) was relatively low due to its high temperature and humidity. The SAR was higher in the colleagues' cluster (20.5%) than in the family cluster (11.8%). Super-spreaders had a longer isolation delay time (p = .004). The Rt of the cluster decreased from the highest value of 3.88 on January 27, 2020 to 1.22 on February 6. Our findings suggest that the predisposing factors of the outbreak included close contact with an infected person, airtight and crowded spaces, temperature and humidity in the space and untimely isolation of patients and quarantine of contacts at the early stage of transmission. Measures to reduce the risk of infection at these gatherings and subsequent tracking of close contacts were effective.