Willingness and influential factors of parents to vaccinate their children with novel inactivated enterovirus 71 vaccines in Guangzhou, China

Predictors of parental acceptance to live attenuated influenza vaccine for children

To determine the influencing factors of Chinese parents' intention and behavior for children to receive live attenuated influenza vaccine during the 2022-2023 influenza season. A theoretical model was developed and included seven constructs, and structural equation modeling was used to test 11 hypotheses. From October 2022 to December 2023, a survey was conducted across 38 medical institutions in four Chinese cities and their subordinate districts, counties, and rural areas. Parents who accompanied their children for vaccinations were selected through a randomization process based on their child's medical card numbers. Measures were taken to minimize method bias, including a diverse geographical representation and random sampling. The survey resulted in the collection of 936 valid responses, exceeding the recommended sample size for structural equation model analysis and providing robust statistical inferences. During the study period, 936 respondents were included in the study. Perceived ease of use was verified to be a predictor of perceived usefulness and perceived value. Perceived usefulness was verified as a predictor of perceived value and behavioral intention. Knowledge was a significant antecedent of perceived value and risk perception of influenza disease. Risk perception of influenza disease was proved to be a significant predictor of perceived value and self-reported vaccination behavior. Perceived value significantly affected behavioral intention, and behavioral intention significantly affected self-reported vaccination behavior. Six demographic variables significantly moderate the theoretical models. The low vaccination coverage of live attenuated influenza vaccine (LAIV) among children in China suggests a need for a deeper understanding of the factors that influence vaccination rates. Particularly, effective strategies are necessary from policymakers and practitioners to elevate childhood LAIV coverage.

Effectiveness of the enterovirus A71 vaccine on hand, foot, and mouth disease: a real-world study in China

OBJECTIVES

For the prevention of hand, foot, and mouth disease (HFMD), enterovirus A71 (EV-A71) vaccines have been used in China since 2016. To better inform vaccination strategies, we assess the real-world effectiveness of EV-A71 vaccination in China.

METHODS

The analysis was based on surveillance data of HFMD caused by EV-A71 in children under the age of 5 in China, along with meteorological and demographic data. The seasonal autoregressive integrated moving average model and the interrupted time series analysis were used to estimate the effectiveness of the EV-A71 vaccination on the EV-A71 HFMD incidence and to predict the counterfactual cases with no EV-A71 vaccine.

RESULTS

Between 2010 and 2018, 6 712 613 cases of HFMD caused by EV-A71 were reported in children under 5 years old in 260 Chinese cities. During 2017-2018, the EV-A71 vaccination was associated with a reduction in EV-A71 HFMD incidence, with a relative risk of 0.83 (95% CI, 0.81-0.86), and an estimated reduction of 297 946 (95% CI, 250 534-346 658) cases. However, this association varied across cities (I2 = 85.6%, p < 0.001) and the effectiveness of the EV-A71 vaccination decreased as population density increased. Higher vaccination coverage was associated with greater effectiveness of the EV-A71 vaccination and an earlier point in EV-A71 case reduction. Specifically, when the vaccination coverage exceeded ∼20%, the relative risk was rapidly reduced to below 0.71 (95% CI, 0.69-0.72).

DISCUSSION

Our study demonstrated that the EV-A71 vaccination was associated with a reduction in the incidence of EV-A71 HFMD, but the association varied with regions and was influenced by vaccination coverage and population density. To optimize EV-A71 HFMD prevention, increasing vaccination coverage (>20%) is recommended for children under 5 years old.

Spatiotemporal Changes and Influencing Factors of Hand, Foot, and Mouth Disease in Guangzhou, China, From 2013 to 2022: Retrospective Analysis

Background

In the past 10 years, the number of hand, foot, and mouth disease (HFMD) cases reported in Guangzhou, China, has averaged about 60,000 per year. It is necessary to conduct an in-depth analysis to understand the epidemiological pattern and related influencing factors of HFMD in this region.

Objective

This study aims to describe the epidemiological characteristics and spatiotemporal distribution of HFMD cases in Guangzhou from 2013 to 2022 and explore the relationship between sociodemographic factors and HFMD incidence.

Methods

The data of HFMD cases in Guangzhou come from the Infectious Disease Information Management System of the Guangzhou Center for Disease Control and Prevention. Spatial analysis and space-time scan statistics were used to visualize the spatiotemporal distribution of HFMD cases. Multifactor ordinary minimum regression model, geographically weighted regression, and geographically and temporally weighted regression were used to analyze the influencing factors, including population, economy, education, and medical care.

Results

From 2013 to 2022, a total of 599,353 HFMD cases were reported in Guangzhou, with an average annual incidence rate of 403.62/100,000. Children aged 5 years and younger accounted for 93.64% (561,218/599,353) of all cases. HFMD cases showed obvious bimodal distribution characteristics, with the peak period from May to July and the secondary peak period from August to October. HFMDs in Guangzhou exhibited a spatial aggregation trend, with the central urban area showing a pattern of low-low aggregation and the peripheral urban area demonstrating high-high aggregation. High-risk areas showed a dynamic trend of shifting from the west to the east of peripheral urban areas, with coverage first increasing and then decreasing. The geographically and temporally weighted regression model results indicated that population density (β=-0.016) and average annual income of employees (β=-0.007) were protective factors for HFMD incidence, while the average number of students in each primary school (β=1.416) and kindergarten (β=0.412) was a risk factor.

Conclusions

HFMD cases in Guangzhou were mainly infants and young children, and there were obvious differences in time and space. HFMD is highly prevalent in summer and autumn, and peripheral urban areas were identified as high-risk areas. Improving the economic level of peripheral urban areas and reducing the number of students in preschool education institutions are key strategies to controlling HFMD.

Application of the double bounded dichotomous choice model to the estimation of parent's willingness to pay for the hand foot mouth disease vaccination: A survey in Selangor, Malaysia

Hand foot and mouth disease (HFMD) is a notifiable viral disease in Malaysia, and is transmitted primarily among young children. Although vaccines for enteroviruses 71 (EV-71) were approved in China against HFMD, the availability and the acceptance of the vaccine in the Malaysia are unknown. This study investigated and ascertained the determinants of willingness-to-pay (WTP) for HFMD vaccination in Selangor Malaysia. This study adopted a cross-sectional, contingent valuation method involving 390 parents of young children aged six and below. The double bounded dichotomous choice (DBDC) approach was employed to assess the WTP for HFMD vaccine among respondents. A bivariate probit model was used to assess the key determinants of WTP for HFMD vaccine, while the mean WTP was measured using the Krinsky and Robb procedure. We found that 279 (71.5%) of parents were willing to pay for the HFMD vaccination. The estimated single bounded mean WTP was MYR460.23 (equivalent to US$ 102.17) for two doses of HFMD vaccination. The double bounded analysis revealed that the vaccine's price, poor education background and lower income were the key factors that significantly affected the WTP, with the estimated mean WTP being MYR394.00 (US$ 87.47). In conclusion, most Malaysian parents are willing to pay for the HFMD vaccination. The estimated WTP identifies the optimal price point for HFMD vaccination in Malaysia. Furthermore, the government should focus on an awareness programme for the HFMD vaccination among parents who have lower income or education level.

Effect of difference between EV-A71 virus epidemic strain and "vaccine strain" on neutralizing antibody titer

Hand, foot and mouth disease was mainly caused by EV-A71 virus. The main antigen structure of VP1 region of EV-A71 was easily varied. Here, we investigated the seroprevalence of EV-A71 based on a large group of healthy individuals in Beijing, China, in order to study the effectiveness of EV-A71 vaccine in a real-world setting. BrCr and the clinical strain isolated from the Chinese mainland in 2008 ("vaccine strain:"CMU4232/BJ/CHN/2008), EV-A71 C4 epidemic strains isolated in 2010, 2013, and 2016, were tested for neutralizing antibodies (NtAb) in every year. Phylogenetic tree analysis of the EV-A71 strains above, as well as amino acid composition homologous sequence analysis were applied. The "vaccine strain" has 83.0% homology with FY23, H07 and FY7VP5. It belongs to the same branch of C4a as 10 C4, 13 C4 and 16 C4, and differs from the amino acid sites 283 and 293 of 16 C4. Compared with "vaccine strains," there was a significant difference between the 50-59 years old age group when the NtAb titer of 16 C4 strain was 1:512-1:1024. Our results suggest that changes in the functional epitopes of NtAb caused by amino acid 283 and 293 loci in EV-A71 strains may affect the production of neutralizing antibodies.

Effect of enterovirus 71 vaccination on the epidemiological characteristics and etiology in hospitalized children with hand-foot-and-mouth disease: A retrospective study from a tertiary children's hospital

Enterovirus 71 (EV71) vaccine for hand-foot-and-mouth disease (HFMD) prevention has been available for several years. However, as a new vaccine, the impact of EV71 vaccination on the epidemiology and etiology of HFMD is currently unclear. The purpose of this study was to compare and analyze the changes of epidemiological characteristics and etiology of HFMD patients after the introduction of EV71 vaccine. The data of hospitalized children with HFMD from 2014 to 2020 were collected from the case record department of a tertiary children hospital of Anhui Province. The changes of epidemiological characteristics, time distribution, disease severity and enterovirus serotypes in hospitalized children were analyzed. A total of 7373 cases of HFMD were reported during 2014 to 2020, including 634 (8.6%) severe cases. The number of cases reached the peak in 2016 (n = 1783) and decreased gradually after EV71 vaccination. The results of etiological test showed the positive rate was 80.5%, in which EV71 accounted for 1599 (21.7%) and CV-A16 accounted for 1028 (13.9%) respectively. The number of patients showed a bimodal distribution throughout the year, which were April to June and October to November. The age distribution changed significantly following the introduction of EV71 vaccine. The proportion of 1-year-old group of post-vaccination was significantly higher than that of pre-vaccination (61.9% vs 50.8%, P < .001). The proportion of HFMD caused by EV71 and severe cases decreased significantly after the vaccination (P < .001 for both). While the comparison of epidemiological characteristics and enterovirus serotypes between unvaccinated and vaccinated cases during 2017 to 2020 showed no significant difference. The dominant enterovirus serotypes of hospitalized HFMD changed significantly after the introduction of EV71 vaccine. The proportion of severe cases decreased significantly after the vaccination, but EV71 was still a major pathogen in patients with severe HFMD. More age-appropriate children are recommended to get vaccinated to establish stronger herd immunity in the population.

Epidemiological characteristics of hand, foot, and mouth disease in Yunnan Province, China, 2008-2019

BACKGROUND

Since 2016, enterovirus 71 (EV71) vaccines have been approved for market entry, and little is known about how the epidemiology of hand, foot, and mouth disease (HFMD) has been affected by the introduction of the vaccines in Yunnan Province. The study describes the epidemiological characteristics of HFMD before and after the introduction of EV71 vaccination in Yunnan Province.

METHODS

Surveillance data collected between 2008 and 2019 were analyzed to produce epidemiological distribution on cases, etiologic composition, and EV71 vaccination coverage, as well as to compare these characteristics before and after EV71 vaccination.

RESULTS

A total of 1,653,533 children received EV71 vaccines from 2016 through 2019 in Yunnan. The annual EV71 vaccination coverage rate ranged from 5.53 to 15.01% among children ≤5 years old. After the introduction of EV71 vaccines, the overall incidence of HFMD increased and reached over 200 cases per 100,000 population-years in 2018 and 2019. However, the case severity and case fatality rate decreased and remained lower than 1 and 0.005% after 2016, respectively. EV71-associated mild, severe and fatal cases sharply decreased. The predominant viral serotype changed to non-EV71/non-CV-A16 enteroviruses which were detected across the whole province.

CONCLUSIONS

Non-EV71/non-CV-A16 enteroviruses became the predominant strain and led to a higher incidence in Yunnan. Expanding EV71 vaccination and strengthening laboratory-based surveillance could further decrease the burden of severe HFMD and detect and monitor emerging enteroviruses.

Willingness and influential factors of parents of 3-6-year-old children to vaccinate their children with the COVID-19 vaccine in China

The impact of Coronavirus disease 2019 (COVID-19) on children aged 3-6 can be severe. Vaccination for COVID-19 is one of the most important primary preventative measures to reduce disease transmission. Parents are hesitant to vaccinate their children against COVID-19 because it was reported in the news that some adults have had adverse reactions to the vaccine. This study aims to investigate the willingness of Chinese parents of 3-6 year old children to vaccinate them with the COVID-19 vaccine and identify what factors influence their decisions. A survey was conducted using a two-stage stratified random sampling method from December 2020 to February 2021. We used univariate analysis and multivariate binary logistic analysis to explore potential factors that may determine the acceptance of the COVID-19 vaccine. Of the 468 parents who participated, 86.75% were willing to vaccinate their children with the COVID-19 vaccine. Parents who were female (OR = 2.591; 95% CI: 0.432-4.689), recognized their children in the high-risk category (OR = 2.494; 95% CI:1.244-5.002), often followed-up with COVID-19 vaccine-related information (OR = 9.065; 95% CI: 3.220-28.654), believed in the safety of the COVID-19 vaccine (OR = 3.068; 95% CI: 1.313-7.168), or thought the COVID-19 vaccine could prevent COVID-19 (OR = 13.750; 95% CI: 2.516-75.140) were more willing to vaccinate their children. To ease parents' hesitation about vaccines, the authority organization should release updated information on the safety and reliability of vaccines, target gender-specific health education for parents, and ask the media to report scientifically support information.

Post-marketing safety surveillance for inactivated Enterovirus 71 vaccines in Jiangsu, China from 2017 to 2019

INTRODUCTION

Two types of enterovirus 71 (EV71) vaccines, manufactured using human diploid (H2) and Vero cells, have been administered in Jiangsu Province, China since 2017. In this study, we evaluated their safety profiles using records collected from the Chinese National Adverse Events Following Immunization (AEFIs) Information System (CNAEFIS) and Electronic Immunization Registries System (EIRS) between 2017 and 2019.

METHODS

Demographic characteristics of the patients, AEFI incidence rates(IRs), symptoms, and time intervals were summarized from the reported AEFI data in the CNAEFIS. Also, the administered doses of the two vaccines were exported from the EIRS to calculate the IRs of AEFIs and thus compare the AEFIs between the two types of EV71 vaccines.

RESULTS

In total, 209, 407, and 344 AEFIs cases following EV71 vaccine administration were reported during 2017, 2018, and 2019, respectively, yielding IRs of 59.2, 48.2, and 54.2 per 100,000 doses, respectively. Fever, irritability, allergic eruptions, fatigue, loss of appetite, redness and induration at the injection site were the most commonly reported AEFIs. No significant differences in rare reactions were found between the two types of EV71 vaccinations. The majority of AEFIs were developed within 30 min to 3 days after administration.

CONCLUSION

EV71 vaccines showed satisfactory safety profiles since their first use 3 years ago in the Jiangsu Province. The AEFI profiles were identical to those in pre-marketing studies; most AEFIs after vaccination were mild and common. More active surveillance studies should be performed to provide more comprehensive post-marketing safety data.

Epidemiology of Hand, Foot, and Mouth Disease Before and After the Introduction of Enterovirus 71 Vaccines in Chengdu, China, 2009-2018

BACKGROUND

Hand, foot, and mouth disease (HFMD) has posed a serious threat to children's health. Three inactivated monovalent enterovirus 71 (EV71) vaccines are proved to be highly efficacious in phase III clinical trials and are now available in China.

METHODS

We analyzed the citywide surveillance data on HFMD cases in Chengdu during 2009-2018, and estimated cumulative first-dose EV71 vaccination coverage among children eligible to EV71 vaccination after August 2016 in Chengdu. Time series susceptible-infected-recovered model was developed to analyze basic reproduction number and herd immunity threshold of HFMD. Overall and serotype-specific HFMD incidences and severity risks were compared before and after the EV71 vaccination.

RESULTS

Among 3 laboratory-identified serotype categories, i.e. EV71, coxsackievirus A16 (CV-A16), and other enteroviruses, the major serotype attributed to HFMD has been changing across years. The cumulative first-dose EV71 vaccination coverage rate was estimated as 60.8% during the study period in Chengdu. By contrast, herd immunity threshold for EV71-related HFMD was 94.0%. After introduction of EV71 vaccines, the overall incidence of HFMD increased 60.8%, mainly driven by 173.7% and 11.8% increased in HFMD caused by other enteroviruses and CV-A16, respectively, which offset a significant reduction in the incidence of HFMD caused by EV71. The overall case-severity risk decreased from 1.4% to 0.3%, with significantly declined presented in all serotype categories.

CONCLUSIONS

The incidence and severity of EV71-related HFMD decreased following implementation of EV71 vaccination. Developing multivalent vaccines and strengthening laboratory-based surveillance could further decline burden of HFMD.

Willingness of parents to vaccinate their 6-60-month-old children with EV71 vaccines: a cross-sectional study in rural areas of northern Jiangsu Province

Enterovirus 71 (EV71) is the dominant pathogen in severe and fatal hand-foot-mouth disease (HFMD) cases. Since 2015, three inactivated EV71 vaccines have been approved in China. The vaccination coverage of the EV71 vaccine has been relatively low, especially in rural areas. A cross-sectional survey from July 19 to August 22, 2018, was conducted in three rural counties of northern Jiangsu Province among parents of children aged 6-60 months. We adopted a pretested validated questionnaire to assess knowledge, awareness, and attitude of HFMD and EV71 vaccines among respondents and used univariate and multivariate binary logistic analyses to explore potential factors associated with the acceptance of EV71 vaccines. Of the 1,112 parents who participated, 87.8% were willing to vaccinate their children with EV71 vaccines. Parents over 40 y old were less likely to have their children vaccinated [adjusted odds ratio (aOR) = 2.12, 95% confidence interval (CI): 1.13-3.97]. Parents who lived in Ganyu (aOR = 0.50, 95% CI: 0.31-0.79) or Xinyi county (aOR = 0.33, 95% CI: 0.20-0.53), had a university or higher degree (aOR = 0.26, 95% CI: 0.11-0.64), had good knowledge of EV71 vaccines (aOR = 0.81, 95% CI: 0.67-0.98), perceived their children's disease susceptibility, and worried about the severity of HFMD had a higher willingness to vaccinate their children. Most parents were willing to vaccinate their children against EV71-related HFMD. Parental age, location, education level, knowledge of EV71 vaccines, concern about susceptibility, and severity of HFMD were all factors that influenced willingness to vaccinate.

Antiviral activity of silymarin in comparison with baicalein against EV-A71

BACKGROUND

The hand, foot and mouth disease (HFMD) is a febrile and exanthematous childhood disease mainly caused by Enterovirus 71 (EV-A71). In severe HFMD, virulent EV-A71 strains can cause acute flaccid paralysis and cardiopulmonary edema leading to death. Currently, no FDA approved antiviral treatment or vaccine is available for EV-A71. Flavonoids such as silymarin and baicalein are known to possess in vitro antiviral properties against viruses. In this study, the cytotoxicity and antiviral activity of silymarin, baicalein and baicalin were investigated.

METHODS

The cytotoxic effects of three flavonoids towards rhabdomyosarcoma (RD) cells were first examined using cell proliferation MTS [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium] assay. Compounds found to be non-cytotoxic in RD cells were evaluated for their in vitro antiviral properties against the EV-A71 subgenotype B4 strain 41 (5865/SIN/000009) using antiviral assays. Viral infectivity was determined by reduction of the formation of plaques in RD cells. For the measurement of RNA copy number, the real time quantitative reverse transcription PCR (qRT-PCR) was used. The most potent compound was further evaluated to determine the mode of action of inhibition by time course, virus attachment and entry assays in Vero cells.

RESULTS

Silymarin was shown to exert direct extracellular virucidal effects against EV-A71 at 50% inhibitory concentration (IC₅₀) of 15.2 ± 3.53 μg/mL with SI of 10.53. Similarly, baicalein exhibited direct extracellular virucidal effects against EV-A71 at a higher IC₅₀ value of 30.88 ± 5.50 μg/mL with SI of 13.64. Besides virucidal activity, silymarin was shown to block both viral attachment and entry of EV-A71 to inhibit infection in Vero cells.

CONCLUSIONS

Silymarin has a stronger inhibition activity against EV-A71 in comparison to baicalein. It could serve as a promising antiviral drug to treat EV-A71 infections.

Addressing Vaccine Hesitancy in China: A Scoping Review of Chinese Scholarship

Despite the well-developed Chinese National Immunization Program, vaccine hesitancy in China is rising. As part of the response, Chinese scholars have studied determinants and proposed solutions to vaccination hesitancy. We performed a scoping review of Chinese literature (2007-2019), drawn from four Chinese databases. We mapped relevant information and presented a systemic account of the proposed determinants and responses to vaccine hesitancy in China. We identified 77 relevant studies that reveal four approaches to vaccine hesitancy. Most Chinese studies define vaccine hesitancy as a problem of vaccine safety and vaccine incident response and place accountability on the level of governance, such as regulation deficits and inappropriate crisis management. A first minority of studies tied vaccination hesitancy to unprofessional medical conduct and called for additional resources and enhanced physician qualifications. A second minority of studies positioned vaccination hesitancy as a problem of parental belief and pointed to the role of media, proposing enhanced communication and education. Chinese literature ties vaccine hesitancy primarily to vaccine safety and medical conduct. Compared to international research, parental concerns are underrepresented. The Chinese context of vaccination scandals notably frames the discussion of vaccination hesitancy and potential solutions, which stresses the importance of considering vaccination hesitancy in specific social and political contexts.

Analysis of factors influencing parents' willingness to accept the quadrivalent influenza vaccine for school-aged children in the Nanhai District, China

Recently, China has attached great importance to promoting immunization, prompting the media, scholars, and public to focus on its coverage and efficacy. This study aimed to understand the factors influencing parental willingness to have their school-aged children vaccinated with quadrivalent influenza vaccines (QIVs). A cross-sectional study through face-to-face interviews was conducted between September and December 2018. Forty-four kindergartens and primary and junior high schools were randomly selected via stratified three-stage cluster sampling. Of 4,430 participants, 24.6% reported having heard of QIV and 24.2% reported having previously received information on QIV. Of these, 42.8% expressed willingness to obtain the QIV for their children. A junior college degree (adjusted odds ratio [aOR] = 1.447; 95% confidence interval [95% CI]: 1.202-1.742), higher influenza knowledge level (medium level, aOR = 1.150, 95% CI, 1.006-1.314; high level, aOR = 1.332, 95% CI, 1.045-1.697), and previous influenza information (aOR = 2.241; 95% CI, 1.604-3.130) were positively correlated with vaccination willingness. In contrast, no previous QIV-related information (aOR = 0.490; 95% CI, 0.418-0.575), no perceived susceptibility of children to influenza (aOR = 0.576; 95% CI, 0.489-0.680), fear of side effects (aOR = 0.599; 95% CI, 0.488-0.735), concern that vaccines need to be carefully administered (aOR = 0.728; 95% CI, 0.593-0.894), and mistrust of new vaccines (aOR = 0.730; 95% CI, 0.628-0.849) were pivotal barriers hindering parents from having their children vaccinated. This study provides baseline information for future immunization programs and delivery, with the ultimate goal of increasing vaccine uptake and minimizing school-wide influenza outbreaks.

Rotavirus Infection and Vaccination: Knowledge, Beliefs, and Behaviors among Parents in Italy

This study was designed to investigate the knowledge, beliefs, and behaviors about rotavirus infection and its vaccination in a sample of parents in Naples, Italy. The survey was conducted between June and December 2018 among parents of children aged 3 months to 3 years. A total of 40.7% of the study subjects declared that they had heard about rotavirus infection and 60.8% and 59.2% were aware about the vaccination and of its availability in Italy. Parents with a child aged <1 year and those who reported the physicians as source of information were more likely to have heard about rotavirus infection and to know that the vaccination is available in Italy. More than half (56.4%) were worried that their children could have a rotavirus gastroenteritis and this was most likely to occur in those who have heard about rotavirus infection. Only 15.3% declared that they had immunized their children against rotavirus infection. Parents who considered it dangerous for their children to contract the rotavirus gastroenteritis, those who considered the rotavirus vaccine useful, and those who had received information by physicians were more likely to have vaccinated their children against the infection. More than half of the parents who did not immunize their children expressed their willingness to vaccinate them. Developing and implementing additional public education programs are needed for better knowledge toward rotavirus infection and vaccination and a high coverage among parents.

Trust collapse caused by the Changsheng vaccine crisis in China

BACKGROUND

The public acceptance and implementation of vaccination programs is essential to prevent infectious diseases. However, vaccine adverse events may cause public panic and eventually lead to an increasing number of populations who were hesitant or refuse to participate in these vaccination programs. In 2018, the Changsheng vaccine crisis broke out in mainland China, and 252,600 unqualified DTP vaccines were reported to be used for child vaccination. In this study, we observed media and public reactions toward the vaccine crisis.

METHODS

This study conducted Internet surveillance by four mainstream indicators from July 15th to August 7th, including social media (WeChat, Sina Weibo), online news and Baidu search index. We also analyzed the emotional perceptions of people in crisis through an online questionnaire survey.

RESULTS

During the crisis, huge number of articles emerged on Internet, 125,882,894 articles (including forwarding) on WeChat friends circle, 1,877,660 Sina Weibo posts, 648,265 online news and 4,986,521 Baidu search indexes. Most of these articles were negative and expressed the public's weak confidence to the China-made vaccines. Public confidence in vaccines was undermined by the actions of the manufacturer and the government.

CONCLUSIONS

The DTP vaccine crisis led to panic about immunization and eroded trust in the immunization program and in the government. Restoring public confidence in Chinese-made vaccines will take a long time, and meticulous management in vaccine production, and strict government regulation will help to alleviate public anxiety about vaccine safety and ultimately restore confidence.