Impact of Adverse Events Following Immunization in Viet Nam in 2013 on chronic hepatitis B infection

How to address vaccine hesitancy? Lessons from National Hepatitis B Immunization Program in China

China, with the severe burden of hepatitis B, plays a significant role in the global efforts towards eliminating hepatitis B disease by 2030. Vaccination is recognized as the most effective measure to prevent infectious diseases. However, vaccine hesitancy remains a significant barrier to achieving herd immunity across diverse populations. To address this issue, the health ministries and public health authorities in China have implemented various measures to encourage hepatitis B vaccination. China's National Hepatitis B Immunization Program, initiated in 1985, has been successful in controlling this vaccine-preventable disease. Given the challenges in eliminating hepatitis B, strengthening the National Hepatitis Immunization Program in China is of utmost importance. Through an analysis of policy documents, reports, and scientific papers, the history of the program was summarized, and effective approaches to address vaccine hesitancy were identified. This will help achieve universal health coverage of vaccines and effectively work towards meeting the goals set for 2030.

Impact of hepatitis B vaccination programs in Vietnam evaluated by estimating HBsAg prevalence

Background

Vietnam introduced a 3-dose hepatitis B (HBV) immunization program comprising 1 dose immediately after birth and 2 or 3 in infancy in the past 20 years, but the impact of the vaccine has not been systematically evaluated. Thus, we conducted this survey aiming to estimate the age-specific chronic HBV prevalence in the general population and to evaluate HBV immunization effectiveness.

Methods

Population-based, four-stage cluster sampling was used in the South Central Coast region of Vietnam. The point-of-care Determine rapid test was used to assess hepatitis B surface antigen (HBsAg) positivity.

Results

A total of 2,075 samples were included in the study. HBsAg prevalence was significantly higher among adults aged 20-39 years than in the population aged 1-19 years (8.0% [95% confidence interval 5.0-12.0] vs. 2.0% [95% confidence interval 1.0-6.0], p<0.01). HBsAg prevalence decreased after implementation of the 3-dose vaccination schedule during infancy from 1997 to 2002, whereas the change in prevalence after implementation of the birth dosing was not significant. A slight increase in HBsAg prevalence was observed for the cohort born in 2011, 2012, and 2013, when there was a vaccine shortage and media reports of immunization resistance.

Conclusions

This is the first population-based assessment of the introduction of the HBV vaccine in Vietnam performed by estimating the HBsAg prevalence across a wide range of ages. The results showed that the HBV immunization policy effectively reduces HBsAg prevalence in general, although birth dosing of the vaccine and low immunization coverage should be carefully monitored.

Media portrayal of vaccine: a content analysis of Vietnam online news about a pentavalent vaccine in the Expanded Program of Immunization

Background: Vaccine hesitancy has become a prominent public health concern, particularly within the coronavirus disease 2019 (COVID-19) pandemic context. Worries about vaccine side effects are often cited as a reason for hesitancy, while media reporting about this topic plays an important role in influencing the public's perspectives about vaccines and vaccination. In Vietnam, during 2012-2013, there were several adverse events following immunization (AEFIs) of Quinvaxem- a pentavalent vaccine in the Expanded Immunization Program, which made big headlines in the media. Such incidences have contributed to changes in vaccination policies and influenced parents' concerns to date. This study explores the portrayal of Quinvaxem in Vietnam digital news during four periods marked by important events. Methods: We performed quantitative and qualitative analysis with a coding framework to identify main content focus, sentiments towards Quinvaxem, and emotional tones in these articles. Results: In total, we included 360 articles into analysis. The amount of news coverage about Quinvaxem increased after AEFIs happened, from 7 articles before AEFIs to 98 and 159 articles in the following periods when AEFIs and investigation into vaccine safety occurred. Most articles are neutral in titles (n=255/360) and content (n=215/360) towards Quinvaxem and do not convey emotional expressions (n=271/360). However, articles focusing on side effects contain negative sentiments and emotional expressions more frequently than articles of other contents while AEFIs details were conflicting across articles. Vaccine sentiments are provoked in the information about vaccine quality and safety, health authority, local delivery, and quoted vaccine opinions. Emotion-conveying elements in 89/360 articles included emotional wording and imagery and expressive punctuation. Conclusions: The heterogeneity of information in online news may reinforce uncertainty about vaccine safety and decrease vaccine intention. Our results have important implications for vaccine communication, given the current plan of the Vietnamese government to roll out COVID-19 vaccination to younger children.

Vaccination against tuberculosis, polio and hepatitis B at birth in Podor health district, Northern Senegal: cross-sectional study of vaccination coverage and its associated factors

BACKGROUND

In Senegal, studies focusing specifically on vaccination coverage with the Bacille de Calmette et Guérin (BCG) vaccine, the birth dose of oral polio vaccine (OPV zero dose) and the birth dose of hepatitis B (HepB-BD) vaccine are insufficient. This study aimed to highlight vaccination coverages with birth doses and factors associated with timely vaccination in Podor health district.

METHODS

A cross-sectional study was carried out from June 19 to 22, 2020. The study population consisted of children aged 12 to 23 months of which 832 were included. A stratified two-stage cluster survey was carried out. The sources of data were home-based records (HBR), health facility registries (HFR) and parental recalls. Timely vaccination refers to any vaccination that has taken place within 24 h after birth. Descriptive analyzes, the chi-square test and logistic regression were performed.

RESULTS

The crude vaccination coverages with BCG, OPV zero dose and HepB-BD were 95.2%, 88.3% and 88.1%, respectively. Vaccination coverages within 24 h after birth were estimated at 13.9%, 30% and 42.1%, respectively. The factors associated with timely HepB-BD are delivery in a health facility (AOR = 1.55; 95% CI = 1.02-2.40), access to television (AOR = 1.63; 95% CI = 1.16-2.29), weighing (AOR = 3.92; 95% CI = 1.97-8.53) and hospitalization of the newborn immediately after birth (AOR = 0.42; 95% CI = 0.28-0.62).

CONCLUSION

Timely administration of birth doses is a challenge in the Podor health district. The solutions would be improving geographic access to health facilities, involving community health workers, raising awareness and integrating health services.

Feasibility, benefits, and cost-effectiveness of adding universal hepatitis B and syphilis testing to routine antenatal care services in Thai Nguyen province, Vietnam

Pregnant women in Vietnam have a high prevalence of hepatitis B virus (HBV) and low prevalence of human immunodeficiency virus (HIV) and syphilis. This study aims to assess the feasibility and benefit of universal testing for HIV, HBV and syphilis in antenatal care (ANC) services. A pilot project was conducted in the Thai Nguyen province of Vietnam between 2012 and 2014. HIV, HBV and syphilis testing were offered to pregnant women. Interventions to eliminate mother-to child-transmission (MTCT) of the three pathogens were provided to infected mothers and their infants. Descriptive analysis was conducted, and the number of infections averted from integrating hepatitis B tests into ANC was estimated. Testing coverage for HIV, HBV and syphilis for the cohort of pregnant women during the pilot project was 98%. Prevalence of HIV, HBV and syphilis infections in this cohort was 0.14%, 7.8%, and 0.03%, respectively. No infant was infected with HIV or syphilis, while HBV infection was diagnosed in 27 infants (13.9%). An estimated 23 mother to child HBV infections were prevented by integrated interventions. The triple prevention of mother-to-child transmission of HIV, HBV and syphilis is feasible. Investment in the expansion of the integrated approach is required to achieve the goal of eliminating MTCT.

Social and behavioral determinants of attitudes towards and practices of hepatitis B vaccine birth dose in Vietnam

BACKGROUND

Hepatitis B virus (HBV) infection is a significant public health issue in Vietnam. Our goal was to understand the determinants of attitudes towards and practices of hepatitis B vaccine birth dose (HepB-BD) in certain regions of Vietnam.

METHOD

A rapid qualitative assessment was conducted in three geographically diverse provinces that reported low coverage (<50%) of HepB-BD. Using purposive sampling of participants, 29 focus group discussions and 20 in-depth interviews were held with caregivers (n = 96), healthcare providers (n = 75), and healthcare administrators (n = 16). Summary notes from these were translated, and inductive coding was used to derive themes. The SAGE Vaccine Hesitancy Determinants Matrix was used as a theoretical framework to organize barriers and facilitators associated with the themes into three levels of influence.

RESULTS

At the individual and group level, caregivers who had higher levels of knowledge about HepB-BD sought the vaccine proactively, while others with lower knowledge faced barriers to the vaccine. Some caregivers reported a negative attitude toward health services because of a language barrier or had generalized concerns about HepB-BD due to media reporting of the past adverse events. Distress arising from potential adverse events was equally common among healthcare providers. At the contextual level, the physical environment made it difficult for caregivers to access healthcare facilities and for providers to conduct outreach. Home births posed a challenge for timely administration of HepB-BD, while health facility births facilitated it. Vaccination-specific barriers included misinterpretation of pre-vaccination screening criteria and asking for the consent of caregivers. Inadequate resources for service delivery negatively influenced HepB-BD attitudes and practices.

CONCLUSION

Given the diversity of barriers associated with attitudes towards and practices of HepB-BD in the three provinces, tailored interventions will be necessary for both demand- and supply-side factors. Rural areas, often with more home births and geographic barriers, may require focused attention.

Hepatitis B Birth Dose among Children in District 2 Hospital, Ho Chi Minh City, Vietnam: Prevalence and Associated Factors

Background

A birth dose of the hepatitis B vaccine will prevent most perinatally acquired infections and offers early protection from horizontal transmission. This article assessed the prevalence of the hepatitis B birth dose and associated factors among children in the District 2 Hospital.

Methods

A prospective cross-sectional study between June and December 2017 recruited parents/caregivers of children aged 12–59 months who were randomly selected at the vaccination department in the District 2 Hospital. The structured questionnaire applied was to collect the characteristics of participants and check the vaccination schedule. The birth dose was defined as the hepatitis B vaccine, which was given to children within 24 hours after birth. Additionally, a semistructured questionnaire was used for interviews and focus group discussions (FGDs) to assess the risk perceptions and barriers to vaccination.

Results

A total of 292 parents/caregivers had a mean age of 32.7 ± 6.8 years; among them, 88.7% were females. Their children had a mean age of 30.3 ± 13.9 months and 71.6% of these children received the hepatitis B birth dose, which correlated with the age of gestation (P < 0.05). In-depth interviews and FGDs found that most participants did not know that hepatitis B could be transmitted through childbirth, and barriers that affected the birth dose vaccine included children being sick, premature infants, or reason relating to physicians.

Conclusions

The rate of hepatitis B birth dose was low, which resulted from associated factors such as premature birth, likely to be linked with false contraindications and beliefs that, potentially, the 2013 incident is still fresh in people's minds. Therefore, strategies to implement policies around the hepatitis B birth dose should be in line with current World Health Organization recommendations and strategies to modify current beliefs about vaccination.

Two media-reported vaccine events in China from 2013 to 2016: Impact on confidence and vaccine utilization

BACKGROUND

China media reported infant deaths following hepatitis B vaccination in late 2013, leading to temporary suspension of hepatitis B vaccine (HepB Event) until the deaths were shown to be coincidental and the vaccine was of standard, good quality. In 2016, a criminal ring in Shandong province that had been purchasing, improperly storing, and reselling Category 2 vaccines (private-sector) to 60 (of 200,000) clinics for 5 years, was exposed, publicized, and prosecuted, and the potential health and epidemiological impacts were investigated to determine whether revaccination was necessary (Shandong Vaccine Event).

METHODS

We assessed parental confidence in vaccines through 9 telephone surveys in 6 and 11 provinces before, during, and after the two events. Provider confidence was assessed through in-person interviews following each event. Vaccine utilization was assessed using Immunization Information Management System data from township clinics.

RESULTS

In the early stages of each event, approximately 30% of parents indicated vaccine hesitancy and 18% said they would refuse routine immunization. Five and nine months after each event, hesitancy and refusal decreased, but not to pre-event levels. During the Shandong Vaccine Event, 49·1% of parents indicated refusal to use Category 2 vaccines; six months later, the rate was 32·8%. Use of HepB decreased by 21% during the first 2 weeks of the HepB Event and by 12·6% during the first 4 weeks of Shandong Vaccine Event, but returned to baseline in less than 3 months. Use of Category 2 vaccine decreased by 49·5% in the first 3 weeks of the Shandong Vaccine Event and by 28·7% 6 months later. After the Shandong Vaccine Event, 64% of clinicians held high confidence in routine immunization, lower than at baseline.

CONCLUSIONS

The two events caused mistrust, loss of confidence, and decreases in use of vaccines by parents and providers. In addition to ensuring immunization program integrity, effective communications and ongoing monitoring of vaccine use and confidence should be included to restore confidence and trust in vaccines.

Epidemiological Characteristics of Advanced Hepatocellular Carcinoma in the Northern Region of Vietnam

Epidemiological characteristics of hepatocellular carcinoma (HCC) in Southern Vietnam has been well reported as in Globocan 2018 while data from the North has still not been fully presented. Therefore, we conducted this retrospective descriptive study on 198 advanced HCC patients treated at 3 major hospitals in Northern Vietnam to describe demographic features, HCC risk factors, and correlation among them in patients with advanced HCC. This information will lead to prevention efforts and provide information for allocating funds for treatment. The median age at diagnosis was 57 years (range: 19-86) and the male/female ratio was 8.9/1. The proportions of hepatitis B virus (HBV) and hepatitis C virus (HCV) infection were 81.3% and 5.6%, respectively. Hepatitis C virus infection rate was significantly higher in patients <50 years old (12.5% vs 3.3%, P = .016). There was no significant difference in age or viral hepatitis infection status by gender. Only 7.6% of patients diagnosed with advanced HCC were asymptomatic. In conclusion, with the high rate of HBV infection among patients with advanced HCC, it is necessary for increasing prevention efforts in HBV screening. Furthermore, HCV infection should be noticed in patients with advanced HCC younger than 50 years old.

Total Dietary Intake and Health Risks Associated with Exposure to Aflatoxin B1, Ochratoxin A and Fuminisins of Children in Lao Cai Province, Vietnam

The health burden of foodborne mycotoxins is considerable, but particularly for children due to their lower detoxification capacity, rapid growth and high intake of food in proportion to their weight. Through a Total Dietary Study approach, the objective was to estimate the dietary exposure and health risk caused by mycotoxins for children under 5 years living in the Lao Cai province in northern Vietnam. A total of 40 composite food samples representing 1008 individual food samples were processed and analyzed by ELISA for aflatoxin B1, ochratoxin A and fumonisins. Results showed that dietary exposure to aflatoxin B1, ochratoxin A and total fumonisins were 118.7 ng/kgbw/day, 52.6 ng/kg bw/day and 1250.0 ng/kg bw/day, respectively. Using a prevalence of hepatitis of 1%, the risk of liver cancer related to exposure of aflatoxin B1 was 12.1 cases/100,000 individual/year. Age-adjusted margin of exposure (MOE) of renal cancer associated with ochratoxin A was 127, while MOE of liver cancer associated with fumonisins was 542. Antropometric data show that 50.4% (60/119) of children were stunted, i.e. height/length for age z-scores (HAZ) below -2, and 3.4% (4/119) of children were classified as wasted, i.e. weight for height z-scores (WHZ) below -2. A significant negative relationship between dietary exposure to individual or mixture of mycotoxins and growth of children was observed indicating that the high mycotoxin intake contributed to stunning in the children studied.

An approach for preparing and responding to adverse events following immunization reported after hepatitis B vaccine birth dose administration

The success of immunization programs in lowering the incidence of vaccine preventable diseases (VPDs) has led to increased public attention on potential health risks associated with vaccines. As a result, a scientifically rigorous response to investigating reported adverse events following immunization (AEFI) and effective risk communications strategies are critical to ensure public confidence in immunization. Globally, an estimated 257 million people have chronic hepatitis B virus (HBV) infection, which causes more than 686,000 premature deaths from liver cancer and cirrhosis. Hepatitis B vaccination is the most effective way to prevent mother-to-child transmission of HBV infection, especially when a timely birth dose is given within 24 h of birth. However, an infant's risk of dying is highest in the neonatal period, and thus, administering HepB-BD within 24 h of birth overlaps with the most fragile period in an infant's life. A working group formed in July 2016 following the publication of the case reports of the effects on vaccination coverage of media reports of infant deaths after HepB-BD administration in China and Vietnam. The goal of the working group was to create a framework and describe best practices for preparing for and responding to AEFI reported after HepB-BD administration, using existing resources. The framework includes six steps, including three preparation steps and three response steps. This document is written for national and regional immunization program staff. Prior to using the framework for preparation and response to AEFIs reported after HepB-BD administration, staff members should be familiar with how AEFI are detected, reported, and investigated in the country. The document might also be of interest to national regulatory staff members who monitor vaccine safety within the country.

Knowledge, attitudes and practices of hepatitis B prevention and immunization of pregnant women and mothers in northern Vietnam

Background and aim

Infection at birth due to mother-to-child (MTC) transmission is the most common cause of chronic hepatitis B virus (HBV) infection in Vietnam. This study was undertaken to examine the knowledge, attitudes, and practices of pregnant women and mothers in Vietnam concerning HBV prevention and immunization.

Methods

A cross-sectional survey was conducted in Quang Ninh and Hoa Binh provinces in 2017. A standardized questionnaire was administered to women when they received care at primary and tertiary maternal health clinics. Multivariate regression was used to identify predictors of HBV knowledge and practices.

Results

Among the 380 women surveyed, 50.3% were pregnant and 49.7% were postpartum. Despite 70.3% of participants reported having received information about HBV during their pregnancy, only 10.8% provided correct answers to all questions regarding HBV transmission routes and preventive measures. Around half of the participants incorrectly believed that HBV is transmitted through sneezing, contaminated water or sharing foods with chronic HBV patients. Although 86.1% of participants believed that HBV vaccination is necessary for infants, only 66.1% responded they were definitely willing to have their own child vaccinated within 24 hours. More than a third of participants expressed concern about having casual contacts or sharing foods with chronic HBV patients. In multivariate analysis, having received information about HBV during their pregnancy was significantly associated with better HBV knowledge score. Delivery at provincial level clinics was a strong predictor for perinatal HBV screening and hepatitis B birth dose administration.

Conclusions

The results highlight the need to prioritize educating pregnant women and mothers in future public health campaigns in order to increase knowledge, reduce misperception, and improve hepatitis B vaccine birth dose coverage in Vietnam.

Media representation of vaccine side effects and its impact on utilization of vaccination services in Vietnam

BACKGROUND

Media representation of vaccine side effects impacts the success of immunization programs globally. Exposure to the media can cause individuals to feel hesitant toward, or even refuse, vaccines. This study aimed to explore the impact of the media on beliefs and behaviors regarding vaccines and vaccine side effects in an urban clinic in Vietnam.

METHODS

A cross-sectional study was conducted in an urban vaccination clinic in Hanoi, Vietnam from November 2015 to March 2016. The primary outcomes of this study were the decisions of Vietnamese subjects after hearing about adverse effects of immunizations (AEFIs) in the media. Socio-demographic characteristics as well as beliefs regarding vaccination were also investigated. Multivariate logistic regression was used to identify factors associated with subjects' behaviors regarding vaccines.

RESULTS

Among 429 subjects, 68.2% of them said they would be hesitant about receiving vaccines after hearing about AEFIs, while 12.4% of subjects said they would refuse vaccines altogether after hearing about AEFIs. Wealthy individuals (OR=0.41; 95% CI=0.19-0.88), and those who displayed trust in government-distributed vaccines (OR=0.20; 95% CI=0.06-0.72) were less likely to display hesitancy regarding vaccination. Receiving information from community health workers (OR=0.44; 95% CI=0.20-0.99) and their relatives, colleagues, and friends (OR=0.47; 95% CI=0.25-0.88) was negatively associated with vaccine hesitancy, but facilitated vaccine refusal after reading about AEFIs in the media (OR=3.12; 95% CI=1.10-8.90 and OR=3.75; 95% CI=1.56-9.02, respectively).

CONCLUSION

Our results reveal a significantly high rate of vaccine hesitancy and refusal among subjects living in an urban setting in Vietnam, after hearing about AEFIs in the media. Vietnam needs to develop accurate information systems in the media about immunizations, to foster increased trust between individuals, health care professionals, and the Vietnamese government.

Acceptability of and willingness to pay for using a smartphone-based vaccination application in a Vietnamese cohort

BACKGROUND

The increasing accessibility of smartphone in Vietnam shows potential in using smartphone applications for vaccination management to improve compliance. However, the acceptability and financial feasibility of using this application in Vietnam have not yet been understood. This study measured the general perception of and willingness to pay (WTP) for using smartphone-based vaccination management applications and their associated factors in Vietnam.

SUBJECTS AND METHODS

A cross-sectional study was conducted between March and April 2016 in an urban vaccination clinic at the Hanoi Medical University in Vietnam. Convenience sampling was used to recruit 429 adult participants who had received vaccinations or whose children were vaccinated. Sociodemographic characteristics and the acceptability of and WTP for using smartphone-based vaccination management applications were evaluated.

RESULTS

Among participants who used smartphone applications, 5% were aware of existing vaccination management applications, of whom 57.9% had previously used the applications. About 69.6% of participants believed that the applications were necessary, 93.7% of them were also willing to use the applications, and 79.1% were willing to pay 92.7 thousand Vietnamese dong (VND) for the applications on average. Participants who were older, unemployed, earned more household income, and having knowledge about functions and benefits of vaccination were less likely to use the vaccination applications. Participants who brought their children to get vaccinated at younger age and with higher level of education were willing to pay more for vaccination applications.

CONCLUSION

High levels of acceptability of, willingness to use, and WTP for smartphone-based vaccination management applications among Vietnamese participants are reported. Increased education and awareness about the benefits of vaccination and vaccination management applications through community health workers might increase the feasibility of implementing such applications and perception toward their usage among young adult smartphone users. In addition, building a stronger relationship with health care providers at hospitals might improve the application's visibility and adoption.

Feasibility and willingness to pay for dengue vaccine in the threat of dengue fever outbreaks in Vietnam

BACKGROUND

The escalation of dengue fever (DF) cases in recent years and the occurrence of a large-scale DF outbreak in 2017 underline the importance of dengue vaccines in Vietnam. Given the potential benefits of the dengue vaccines and the need for copayment by the private sector, this study aims to evaluate the willingness to pay (WTP) for the dengue vaccines in patients with DF in Northern Vietnam.

METHODS

A cross-sectional study was conducted on 330 in-and-out patients with DF admitted to the Bach Mai Hospital. We used the contingent valuation method to evaluate the WTP for dengue vaccines. Socioeconomic and clinical characteristics were also investigated. Multivariate interval and logistic regression models were used to estimate the average amount of WTP and identify the factors associated with the WTP.

RESULTS

Around 77.3% patients were willing to pay an average amount of US$ 67.4 (95% CI=57.4-77.4) for the vaccine. People of higher ages, those having health insurance, those traveling in the past 15 days or suffering from anxiety/depression were less likely to be willing to pay for the dengue vaccine. However, people having a longer duration of DF or having problems with mobility were positively associated with WTP for the dengue vaccine. Patients educated to more than high school levels (Coeff.=31.31; 95% CI=3.26-59.35), those in the richest quintile (Coeff.=62.76; 95% CI=25.40; 100.13), or those having a longer duration of the disease (Coeff.=6.18; 95% CI=0.72-11.63) were willing to pay a higher amount.

CONCLUSION

This study highlights a relatively high rate and amount of WTP for the dengue vaccine among patients with DF. Psychological counseling services as well as educational campaigns should be undertaken to improve the WTP for the vaccine. Moreover, government subsidies should be given to increase the coverage of the vaccine in the future, especially for the poor.

Loss of confidence in vaccines following media reports of infant deaths after hepatitis B vaccination in China

BACKGROUND

China reduced hepatitis B virus (HBV) infection by 90% among children under 5 years old with safe and effective hepatitis B vaccines (HepB). In December 2013, this success was threatened by widespread media reports of infant deaths following HepB administration. Seventeen deaths and one case of anaphylactic shock following HBV vaccination had been reported.

METHODS

We conducted a telephone survey to measure parental confidence in HepB in eleven provinces at four points in time; reviewed maternal HBV status and use of HepB for newborns in birth hospitals in eight provinces before and after the event; and monitored coverage with hepatitis B vaccine and other programme vaccines in ten provinces.

RESULTS

HepB from the implicated company was suspended during the investigation, which showed that the deaths were not caused by HepB vaccination. Before the event, 85% respondents regarded domestic vaccines as safe, decreasing to 26.7% during the event. During the height of the crisis, 30% of parents reported being hesitant to vaccinate and 18.4% reported they would refuse HepB. Use of HepB in the monitored provinces decreased by 18.6%, from 53 653 doses the week before the event to 43 688 doses during the week that Biokangtai HepB was suspended. Use of HepB within the first day of life decreased by 10% among infants born to HBsAg-negative mothers, and by 6% among infants born to HBsAg-positive mothers. Vaccine refusal and HepB birth dose rates returned to baseline within 2 months; confidence increased, but remained below baseline.

CONCLUSIONS

The HBV vaccine event resulted in the suspension of a safe vaccine, which was associated with a decline of parental confidence, and refusal of vaccination. Suspension of a vaccine can lead to loss of confidence that is difficult to recover. Timely and credible investigation, accompanied by proactive outreach to stakeholders and the media, may help mitigate negative impact of future coincidental adverse events following immunization.

Trends in mortality burden of hepatocellular carcinoma, cirrhosis, and fulminant hepatitis before and after roll-out of the first pilot vaccination program against hepatitis B in Peru: An analysis of death certificate data

The first pilot vaccination program against hepatitis B in Peru was implemented in the hyperendemic Abancay province in 1991. To assess the impact of vaccination on mortality rates of hepatitis B-related hepatocellular carcinoma (HCC), cirrhosis, and fulminant hepatitis, we compared mortality trends before (1960-1990) and after (1991-2012) roll-out of the vaccination program, using death certificate data from the Municipalidad Provincial de Abancay. Our results showed that, following program roll-out, the overall mortality rates (per 100,000 population) decreased from 9.20 to 3.30 for HCC (95% CI, 1.28-10.48%; P<0.014), from 16.0 to 6.3 for cirrhosis (95% CI, 3.20-16.10%; P<0.004), and from 34.80 to 1.28 for fulminant hepatitis (95% CI, 16.70-50.30%; P<0.001). The absolute number of deaths attributable to cirrhosis (10 [8.80%] vs. 0.0%; P<0.001) and fulminant hepatitis (83 [40.0%] vs. 5 [19.20%]; P<0.026) decreased in 5-14-year-old children following vaccination. These findings showed reduced mortality rates of hepatitis B-related liver diseases, particularly cirrhosis and fulminant hepatitis in children under 15years, following implementation of the vaccination program against hepatitis B.