新型Ⅱ型口服脊髓灰质炎减毒活疫苗研究进展

全球消灭脊髓灰质炎行动(GPEI)于2016年4月调整脊髓灰质炎疫苗免疫接种战略,将三价口服脊髓灰质炎疫苗(tOPV)转换为二价口服脊髓灰质炎疫苗(bOPV),并在全球全面撤出Ⅱ型口服脊髓灰质炎减毒活疫苗(OPVⅡ)。然而在OPVⅡ撤出以后,亚洲和非洲多地暴发Ⅱ型循环疫苗衍生脊髓灰质炎病毒(cVDPVⅡ)。为了彻底消灭脊髓灰质炎病毒,GPEI于2010年启动研发新型Ⅱ型口服脊髓灰质炎减毒活疫苗(nOPVⅡ),并于近年开始考虑是否有必要重启OPV。本文概述了OPVⅡ撤出前后cVDPVⅡ的流行病学情况,影响OPV重启的相关因素以及nOPVⅡ相关研究进展。     

“This is a Pakhtun disease”: Pakhtun health journalists’ perceptions of the barriers and facilitators to polio vaccine acceptance among the high-risk Pakhtun community in Pakistan

IntroductionPakistan is one of only three poliomyelitis-endemic countries in the world. Twelve wild poliovirus (WPV) cases were recorded in the country in 2018. Even though resistance to oral polio vaccine (OPV) has decreased over time, there are still pockets of communities, mostly ethnic Pakhtun living in the Khyber Pakhtunkhwa (KP) province, that resist OPV. Although local journalists may be important sources of health information, past studies have overlooked their role in this context. The purpose of this study was to examine Pakhtun health journalists’ beliefs regarding OPV and their views of the barriers and facilitators that influence OPV acceptance or hesitancy in their communities.MethodsWe recruited and interviewed 33 Pakhtun journalists covering health issues for diverse media outlets in high-risk districts for WPV of the KP province. The semi-structured interviews were translated, transcribed, and analyzed for themes.ResultsThe participants strongly supported OPV and advocated that children in their own families and communities get vaccinated against polio. At the same time, they felt that their communities faced more urgent health needs that were not addressed by the government. They identified barriers at the media organizational level operating against accurate coverage of OPV, including financial and time constraints, a lack of checks and balances, and limited health literacy. They regarded press releases issued by the officials associated with OPV campaigns as the main facilitators in the coverage of OPV. The participants perceived lack of community trust in the government, security concerns, and community members’ religious beliefs as the major impediments to increase in uptake of OPV.ConclusionPakhtun health journalists have the potential to be important partners in national polio eradication initiatives. They should receive culturally sensitive training in local languages at appropriate literacy levels. We also suggest direct involvement of journalists in community mobilization efforts.     

Refusal of oral polio vaccine in northwestern Pakistan: A qualitative and quantitative study

Background

Refusal of the oral polio vaccine (OPV) is a difficulty faced by the Polio Eradication Initiative (PEI) in multiple endemic areas, including the Khyber Pakhtunkhwa Province (KPP), Pakistan. In 2007, we investigated community perceptions of the OPV and estimated the prevalence of OPV refusal in three districts in Swat Valley, KPP, a polio-endemic area.

Methods

Qualitative data concerning community perceptions were collected by focus group discussions among lady health workers (LHWs) and mothers with children <1 year old and by key informant interviews with local health managers and officials. Quantitative data collection followed using a questionnaire survey of 200 LHWs and a cluster sampling survey of 210 mothers (per district) with children <1 year old.

Results

The qualitative assessments identified the grounded theory of OPV refusal involving facts known by the residents that are related to the OPV (too frequent OPV campaigns, an OPV boycott in northern Nigeria in 2003 and that birth control is viewed as is against Islam), the local interpretations of these facts (perceptions that OPV contained birth control or pork, that OPV was a foreign/central plot against Muslims, and that the vaccination was against the Hadith and the fate determined by God) and different manifestations of OPV refusal. Among the three districts studied, the proportion of LHWs who encountered OPV refusal ranged from 0 to 33%, whereas among the districts, the proportions of mothers unwilling to give OPV to their children ranged from 0.5 to 5.7%. Refusal of other injectable vaccines was almost equally prevalent for reasons that were very similar.

Conclusions

The PEI needs to reflect local value system in the path to polio eradication in the studied districts in the Swat Valley. The religious and cultural values as well as the interpretation of the international political situation are of particular importance.     

“Everybody just wants to do what's best for their child”: Understanding how pro-vaccine parents can support a culture of vaccine hesitancy

BackgroundAlthough a large majority of parents vaccinate their children, vaccine hesitancy has become more widespread. It is not well understood how this culture of vaccine hesitancy has emerged and how it influences parents’ decisions about vaccine schedules.ObjectiveWe sought to examine how attitudes and beliefs of parents who self-report as pro-vaccine are developed and contribute to immunization decisions, including delaying or spacing vaccines.MethodsOpen-ended, in-depth interviews (N = 23) were conducted with upper-middle class parents with young children living in Philadelphia. Interview data were coded and key themes identified related to vaccine decision-making.ResultsParents who sought out vaccine information were often overwhelmed by the quantity and ambiguity when interpreting that information, and, consequently, had to rely on their own instinct or judgment to make vaccine decisions. In particular, while parents in this sample did not refuse vaccines, and described themselves as pro-vaccine, they did frequently delay or space vaccines. This experience also generated sympathy for and tolerance of vaccine hesitancy in other parents. Parents also perceived minimal severe consequences for deviating from the recommended immunization schedule.ConclusionThese findings suggest that the rise in and persistence of vaccine hesitancy and refusal are, in part, influenced by the conflicts in the information parents gather, making it difficult to interpret. Considerable deviations from the recommended vaccination schedule may manifest even within a pro-vaccine population due to this perceived ambiguity of available information and resulting tolerance for vaccine hesitancy.     

Factors influencing vaccine acceptance and hesitancy in three informal settlements in Lusaka,Zambia

IntroductionHeterogeneous coverage threatens to compromise the effectiveness of immunization programs in Zambia. Demand-creation initiatives are needed to address this; however, there is incomplete understanding of why vaccine coverage is suboptimal. We investigated overarching perceptions on vaccine acceptability, hesitancy, and accessibility at three informal settlements in Lusaka, Zambia.MethodsNested within a cholera vaccination uptake study, we sought to understand overarching perceptions on vaccines’ hesitancy in three informal settlements in Lusaka, Zambia. We conducted 48 focus group discussions with a convenience sample of laypersons, lay healthcare workers, neighbourhood health committee members and vaccinators.ResultsBoth laypersons and community-based health actors reported high vaccine acceptance though several sources of hesitancy were reported. Traditional remedies, alcohol use and religious beliefs emerged as drivers of vaccine hesitancy, likely reinforced by a background of distrust towards western medicine. Also mentioned were previous adverse events, fear of injections and low perceived need for immunization. Limited understanding of how vaccines work and overlapping local terms for vaccine and other medical concepts created confusion and inaccurate views and expectations. Some reported refusing injections to avoid pain and perceived risk of infection. Discussants emphasised the importance of education and preferred mobile immunization campaigns, with weekend to reach those with poor access and delivered by a combination of professional and volunteer workers.ConclusionsVaccine hesitancy in Zambia is underpinned by many factors including personal experiences with vaccinations, alternative belief models, limited knowledge, deep misunderstanding about how vaccines work, and barriers to access. To overcome these, community-driven models that incorporate factual communication by professionals and operate outside of traditional hours, may help. Better research to understand community preferences for vaccine uptake could inform interventions to improve immunization coverage in Zambia.     

中国3个地区儿童家长对国家免疫规划类疫苗犹豫现状研究

目的 了解我国儿童家长对国家免疫规划类疫苗犹豫发生率和影响因素,并探索不同种类疫苗的犹豫现状。方法 在北京市通州区、四川省成都市及甘肃省白银市进行横断面调查,采用成比例概率抽样和便利抽样的方法选取符合标准的研究对象进行问卷调查。结果 共纳入研究对象3 592人,38.22%的家长完全接受所有疫苗,59.35%的家长给儿童接种了所有疫苗但表示有轻微的担忧,2.42%的儿童家长对国家免疫规划类疫苗有疫苗犹豫行为。其中家长产生疫苗犹豫最多的是脊髓灰质炎疫苗（0.89%）,其次为百白破疫苗（0.70%）和甲肝疫苗（0.64%）。疫苗犹豫产生的主要原因是对疫苗的风险效益判断（31.03%）,其次为家长的认知情况较低（21.84%）,第三为交通/时间因素带来的不便（21.84%）。结论 我国儿童家长对国家免疫规划类疫苗犹豫行为的发生率较低,但半数以上家长对疫苗持担忧态度。进一步改进我国免疫规划体系的服务质量,加强疫苗相关知识宣教,对减少疫苗犹豫是至关重要的。     

Vaccine hesitancy against COVID-19 vaccine over time in Nigeria

IntroductionWhile COVID-19 pandemic is an ongoing threat for our lives, the rapid development of effective vaccines against COVID-19 provided us hopes for manageable disease control. However, vaccine hesitancy across the globe is a concern which could attenuate efforts of disease control. This study examined the extent and trend of vaccine hesitancy in Nigeria.MethodsThe COVID-19 National Longitudinal Phone Survey conducted between 2020 and 2021 was used for the analysis. The extent and trend of vaccine hesitancy across different zones within Nigeria, over time, as well as reasons of the hesitancy were evaluated.ResultsVaccine hesitancy was more prevalent in southern zones, which on average have better socioeconomic status than northern zones. Overtime, vaccine hesitancy became more prevalent, and respondents became more resistant to the COVID-19 vaccine across the country.ConclusionWhile the nature of interventions to improve the uptake of COVID-19 vaccine should differ by regions due to differential barriers to vaccination, it might be important to prebunk and debunk any misinformation related to COVID-19 vaccine to mitigate the vaccine hesitancy across the country.     

“They're trying to bribe you and taking away your freedoms”: COVID-19 vaccine hesitancy in communities with traditionally low vaccination rates

Vaccination is an essential public health intervention to control the COVID-19 pandemic. A minority of Canadians, however, remain hesitant about COVID-19 vaccines, while others outright refuse them. We conducted focus groups to gauge perceptions and attitudes towards COVID-19 vaccines in people who live in a region with historically low rates of childhood vaccination. Participants discussed their perception of COVID-19 vaccines and their intention to get vaccinated, and the low rate of COVID-19 vaccine uptake in Manitoba’s Southern Health Region compared to other regions in Canada. We identified three drivers of vaccine hesitancy: (1) risk perceptions about COVID-19 and the vaccines developed to protect against it, (2) religious and conservative views; and (3) distrust in government and science. Participant proposed recommendations for improving communication and uptake of the COVID-19 vaccines included: public health messages emphasising the benefits of vaccination; addressing the community’s specific concerns and dispelling misinformation; highlighting vaccine safety; and emphasising vaccination as a desirable behaviour from a religious perspective. Understanding the specific anxieties elicited by COVID-19 vaccines in areas with low childhood immunization rates can inform risk communication strategies tailored to increase vaccination in these specific regions. This study adds important information on potential reasons for vaccine hesitancy in areas with historically low rates of childhood vaccination, and provides important lessons learned for future emergencies in terms of vaccine hesitancy drivers and effective risk communication to increase vaccine uptake.     

The societal cost of vaccine refusal: A modelling study using measles vaccination as a case study

BackgroundIncreasing vaccine hesitancy and refusal poses a challenge to public health as even small reductions in vaccine uptake can result in large outbreaks of infectious diseases. Here we estimate the societal costs of vaccine refusal using measles as a case study.MethodsWe developed a compartmental metapopulation model of measles transmission to explore how the changes in the size and level of social mixing between populations that are “pro-vaccination”, and “anti-vaccination” impacts the burden of measles. Using the projected cases and deaths, we calculated the health, healthcare, direct medical costs, and productivity loss associated with vaccine refusal. Using measles in England as a case study, we quantified the societal costs that each vaccine refusal imposes on society.FindingsWhen there is a high level of mixing between the pro- and anti-vaccination populations, those that refuse to be vaccinated benefit from the herd immunity afforded by the pro-vaccination population. At the same time, their refusal to be vaccinated increases the burden in those that are vaccinated due to imperfect vaccines, and in those that are not able to be vaccinated due to other underlying health conditions. Using England as a case study, we estimate that this translates to a societal loss of GBP 292 million and disease burden of 17 630 quality-adjusted-life-years (sensitivity range 10 594–50 379) over a 20-year time horizon. Of these costs, 26 % are attributable to healthcare costs and 74 % to productivity losses for patients and their carers. This translates to a societal loss per vaccine refusal of GBP 162.21 and 0.01 (0.006–0.03) quality-adjusted-life-years.InterpretationOur findings demonstrate that even low levels of vaccine refusal can have a substantial and measurable societal burden on the population. These estimates can support the value of investment in interventions that address vaccine hesitancy and vaccine refusal, providing not only improved public health but also potential economic benefits to society.     

Zero-dose children and the immunisation cascade: Understanding immunisation pathways in low and middle-income countries

IntroductionZero-dose prevalence refers to children who failed to receive any routine vaccination. Little is known about the “immunisation cascade” in low- and middle-income countries (LMICs), defined as how children move from zero dose to full immunisation.MethodsUsing data from national surveys carried out in 92 LMICs since 2010 and focusing on the four basic vaccines delivered in infancy (BCG, polio, DPT and MCV), we describe zero-dose prevalence and the immunisation cascade in children aged 12 to 23 months. We also describe the most frequent combinations of vaccines (or co-coverage) among children who are partially immunized. Analyses are stratified by country income groups, household wealth quintiles derived from asset indices, sex of the child and area of residence. Results were pooled across countries using child populations as weights.ResultsIn the 92 countries, 7.7% were in the zero-dose group, and 3.3%, 3.4% and 14.6% received one, two or three vaccines, respectively; 70.9% received the four types and 59.9% of the total were fully immunised with all doses of the four vaccines. Three quarters (76.8%) of children who received the first vaccine received all four types. Among children with a single vaccine, polio was the most common in low- and lower-middle income countries, and BCG in upper-middle income countries. There were sharp inequalities according to household wealth, with zero-dose prevalence ranging from 12.5% in the poorest to 3.4% in the wealthiest quintile across all countries. The cascades were similar for boys and girls. In terms of dropout, 4% of children receiving BCG did not receive DPT1, 14% receiving DPT1 did not receive DPT3, and 9% receiving DPT3 did not progress to receive MCV.Interpretation.Focusing on zero-dose children is particularly important because those who are reached with the first vaccine are highly likely to also receive remaining vaccines.     

Parental Perspectives on Immunizations: Impact of the COVID-19 Pandemic on Childhood Vaccine Hesitancy

Childhood vaccine hesitancy has been studied extensively before the COVID-19 pandemic. The pandemic presented new barriers to pediatric vaccinations. Furthermore, the development of COVID-19 vaccines has complicated factors underlying vaccine hesitancy. We performed a cross-sectional mobile phone-based survey at Children’s Hospital Los Angeles querying parents regarding perspectives on vaccines before and during the pandemic. Our primary aim was to understand the impact of the pandemic on routine childhood vaccine hesitancy. Secondarily, we examined intent to vaccinate, COVID-19 vaccine hesitancy, and key contributing demographic factors. Among 252 participants, we found overall increased childhood vaccine hesitancy (p?=?0.006), increased risk perception (p?=?0.006), and unchanged vaccine confidence during the COVID-19 pandemic. Increased hesitancy did not translate into decreased intent to vaccinate with routine childhood vaccines or influenza vaccines. During the pandemic, households with higher income (50–99 K, >?100 K) correlated with decreased routine childhood vaccine hesitancy, while Hispanic ethnicity and African American race had increased risk perception. For COVID-19 vaccine hesitancy, households with higher income (>?100 K) correlated with decreased hesitancy, while non-White ethnicity and race had increased risk perception. We found that routine childhood vaccine hesitancy increased during the COVID-19 pandemic, mainly due to increased risk perception. Key contributing demographic factors behind both childhood vaccine hesitancy and COVID-19 vaccine hesitancy included household income and race. Understanding factors behind routine childhood vaccine hesitancy is crucial to maintaining pediatric vaccination rates and promoting vaccine confidence during and after the COVID-19 pandemic.

     

The immunogenicity of oral poliomyelitis vaccine in a primary vaccination series at 2, 4 and 6 months given concurrently with Hib,hepatitis B and diphtheria,tetanus and whole-cell pertussis vaccines administered as three separate injections or as a combination pentavalent vaccine

The increasing number of infant immunisations has spurred development of novel combination vaccines. This investigation assesses the immunogenicity of oral poliomyelitis vaccine (OPV) under current and possible new conditions, to help ensure vaccination regimes continue to provide optimal protection against polio in the final stages of polio eradication. Neutralising antibody titres were measured in approximately 200 infants immunised with OPV at 2, 4 and 6 months in tandem with either a combined pentavalent liquid Haemophilus influenza B (Hib), hepatitis B, diphtheria, tetanus and whole-cell pertussis vaccine or three separate but concurrently administered licensed vaccines (diphtheria, tetanus and whole-cell pertussis (DTP), lyophilised Hib, and hepatitis B). Following three doses of OPV, at least 98% of infants demonstrated neutralising antibodies at 1:8 to each poliovirus type under both vaccination regimes, and geometric mean titres (GMTs) well above the suggested protective titre were also observed for all poliovirus types. OPV appears to be effective not only in producing protective antibody titres in an extremely high proportion of infants when given in combination with currently licensed vaccines, but also when administered together with the combination pentavalent vaccine under study. This is encouraging for the continued role of OPV in infant immunisation.     

Childhood full and under-vaccination in Nigeria, 2013

BackgroundNigeria’s government is challenged with vaccinating the world’s third largest birth cohort within a culturally and socioeconomically diverse country. This study estimated full childhood immunization coverage in Nigeria and characterizes the association between vaccination status and urbanicity, region of residence, ethnicity, and other factors.MethodsIn 2013, households throughout Nigeria were enrolled in the Demographic and Health Survey which included questions about vaccination. We defined full vaccination of a child as having received a single dose of bacillus Calmete-Guerin (BCG), one dose of measles-containing vaccine (MCV), three doses of diphtheria, pertussis, tetanus (DPT), and four doses of oral polio vaccine (OPV). Using a multinomial logistic regression model, full vaccination and under-vaccination versus non-vaccination was regressed onto various demographic and socioeconomic characteristics.ResultsAmong 5759 children 1 year of age, 25.5% were fully vaccinated, 47.9% were under-vaccinated, and 26.6% had not received any vaccinations. Children were more likely to be fully vaccinated if they belonged to wealthier families, resided in southern regions of the country, were Christian, belonged to the Igbo or Yoruba ethnic group, had mothers who made ≥5 antenatal care visits, delivered at an institution, or were more highly educated.ConclusionsFull vaccination among children in Nigeria is exceptionally low by global standards and certain groups, such as Muslims and individuals in northern regions who are higher risk of non- or under-vaccination should be targeted by vaccination programs. Providing a wide range of health care services for mothers and pregnant women could improve full vaccination of children.     

Prevalence and characteristics of HPV vaccine hesitancy among parents of adolescents across the US

BackgroundWhile many clinicians encounter parents or adolescents who refuse HPV vaccine, little is known about the prevalence of hesitancy for HPV vaccine nationally or its association with vaccination.MethodsIn April 2019, we surveyed families with adolescents 11–17 years using a national online panel (Knowledge Panel®) as the sampling frame. We assessed the prevalence of HPV vaccine hesitancy with the validated 9-item Vaccine Hesitancy Scale (VHS). We used multivariate analyses to assess demographic factors associated with HPV vaccine hesitancy. We also assessed practical barriers to receipt of HPV vaccine and the relationship between barriers and hesitancy. Finally, we evaluated the association between both HPV vaccine hesitancy and practical barriers on HPV vaccine receipt or refusal.Results2,177 parents out of 4,185 sampled (52%) completed the survey, 2,020 qualified (lived with adolescent). Using a VHS cut-off score > 3 out of 5 points, 23% of US parents were hesitant about HPV vaccine. Hesitancy was lower among those with Hispanic ethnicity. At least one out of five parents disagreed that the HPV vaccine is beneficial for their adolescent, that the vaccine is effective, protects against HPV-related cancers, or that they followed their adolescent’s health-care provider’s recommendation about the vaccine. Many were concerned about vaccine side effects and the novelty of the vaccine. Adolescents living with vaccine-hesitant parents were less than one-third as likely to have received the vaccine (RR = 0.29, 95% CI 0.24, 0.35) or completed the vaccine series (RR = 0.29, 95% CI 0.23, 0.36), and were 6-fold more likely to have refused the vaccine because of parental vaccine-related concerns (RR = 6.09, 95% CI = 5.26, 7.04). Most practical barriers were independently associated with vaccine receipt but not with vaccine refusal.ConclusionsHPV vaccine hesitancy is common nationally and strongly related to both under-vaccination and vaccine refusal.     

The contribution of the polio eradication initiative to narrowing the gaps in the health workforce in the African Region

IntroductionThe Global Polio Eradication Initiative (GPEI) massively invested to overcome the crippling disease in countries of the WHO African Region. In the context of economic crisis, almost all countries in the Region lack an adequate health workforce. Large amounts were invested by GPEI in human resources. This paper shows how the human resources funded by polio contributed to narrowing the gaps in health workforce and helped strengthening and supporting other priority health programmes in Angola, Chad, DRC, Nigeria, Tanzania, and Togo.MethodsThe health workforce strengthening methods used in the five different countries included the following: policy development and strategic planning, microplanning, capacity building of public health and community workers, implementation and services, monitoring and evaluation, advocacy and social mobilization, and programme review.ResultsStaff funded by polio helped with achieving good coverage in vitamin A and insecticide-treated mosquito nets (Angola, Chad); improvement of EPI and integrated disease surveillance indicators, improved quality of data (all five countries), administrative support, smooth introduction of new vaccines, increased case detection, and early isolation of patients suffering from the Guinea worm (Chad); reduction of cholera, extension of directly observed TB short course treatment (Democratic Republic of Congo); significant staff performance improvement (Nigeria).DiscussionGPEI investment achieved far beyond its primary goal, and contributed to narrowing the gaps in the health workforce in countries of the African Region, as demonstrated by the best practice documentation exercise. We recommend that expertise and experience of polio funded staff should be leveraged to strengthen, expand and support other public health programmes.     

Factors affecting COVID-19 vaccine hesitancy among healthcare providers in 23 countries

BackgroundSeveral early COVID-19 studies aimed to assess the potential acceptance of a vaccine among healthcare providers, but relatively few studies of this population have been published since the vaccines became widely available. Vaccine safety, speed of development, and low perceived disease risk were commonly cited as factors for COVID-19 vaccine hesitancy among this group.Purpose and methodsIn a secondary analysis based on a cross-sectional, structured survey, the authors aimed to assess the associations between self-reported vaccine hesitancy and a number of sociodemographic and COVID-19 vaccine perception factors using data from 3,295 healthcare providers (physicians, nurses, community health workers, other healthcare providers) in 23 countries.Findings494 (15.0%) of the participants reported vaccine hesitancy, of whom 132 (4.0%) would outright refuse to accept a COVID-19 vaccine. Physicians were the least hesitant. Vaccine hesitancy was more likely to occur among those with less than the median income and, to a lesser degree, younger age. Safety and risk concerns and lack of trust that vaccines would be equitably distributed were strongly associated with hesitancy, less so were concerns about the efficacy of COVID-19 vaccines.InterpretationFindings suggest a need to address safety and risk concerns through tailored messaging, training, and/or incentive approaches among healthcare providers, as well as the need for international and national vaccination efforts to ensure equitable distribution.