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Vaccine Apr 2014Vaccine "hesitancy" is an emerging term in the literature and discourse on vaccine decision-making and determinants of vaccine acceptance. It recognizes a continuum... (Review)
Review
Vaccine "hesitancy" is an emerging term in the literature and discourse on vaccine decision-making and determinants of vaccine acceptance. It recognizes a continuum between the domains of vaccine acceptance and vaccine refusal and de-polarizes previous characterization of individuals and groups as either anti-vaccine or pro-vaccine. The primary aims of this systematic review are to: 1) identify research on vaccine hesitancy; 2) identify determinants of vaccine hesitancy in different settings including its context-specific causes, its expression and its impact; and 3) inform the development of a model for assessing determinants of vaccine hesitancy in different settings as proposed by the Strategic Advisory Group of Experts Working Group (SAGE WG) for dealing with vaccine hesitancy. A broad search strategy, built to capture multiple dimensions of public trust, confidence and hesitancy around vaccines, was applied across multiple databases. Peer-reviewed studies were selected for inclusion if they focused on childhood vaccines [≤ 7 years of age], used multivariate analyses, and were published between January 2007 and November 2012. Our results show a variety of factors as being associated with vaccine hesitancy but they do not allow for a complete classification and confirmation of their independent and relative strength of influence. Determinants of vaccine hesitancy are complex and context-specific - varying across time, place and vaccines.
Topics: Child; Child, Preschool; Decision Making; Health Knowledge, Attitudes, Practice; Humans; Infant; Patient Acceptance of Health Care; Vaccination; Vaccines
PubMed: 24598724
DOI: 10.1016/j.vaccine.2014.01.081 -
European Respiratory Review : An... Dec 2022Respiratory syncytial virus (RSV) significantly impacts the health of older and high-risk adults (those with comorbidities). We aimed to synthesise the evidence on RSV... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Respiratory syncytial virus (RSV) significantly impacts the health of older and high-risk adults (those with comorbidities). We aimed to synthesise the evidence on RSV disease burden and RSV-related healthcare utilisation in both populations.
METHODS
We searched Embase and MEDLINE for papers published between 2000 and 2019 reporting the burden and clinical presentation of symptomatic RSV infection and the associated healthcare utilisation in developed countries in adults aged ≥60 years or at high risk. We calculated pooled estimates using random-effects inverse variance-weighted meta-analysis.
RESULTS
103 out of 3429 articles met the inclusion criteria. Among older adults, RSV caused 4.66% (95% CI 3.34-6.48%) of symptomatic respiratory infections in annual studies and 7.80% (95% CI 5.77-10.45%) in seasonal studies; RSV-related case fatality proportion (CFP) was 8.18% (95% CI 5.54-11.94%). Among high-risk adults, RSV caused 7.03% (95% CI 5.18-9.48%) of symptomatic respiratory infections in annual studies, and 7.69% (95% CI 6.23-9.46%) in seasonal studies; CFP was 9.88% (95% CI 6.66-14.43%). Data paucity impaired the calculation of estimates on population incidence, clinical presentation, severe outcomes and healthcare-related utilisation.
CONCLUSIONS
Older and high-risk adults frequently experience symptomatic RSV infection, with appreciable mortality; however, detailed data are lacking. Increased surveillance and research are needed to quantify population-based disease burden and facilitate RSV treatments and vaccine development.
Topics: Humans; Aged; Respiratory Syncytial Virus Infections; Developed Countries; Hospitalization; Respiratory Syncytial Virus, Human; Respiratory Tract Infections
PubMed: 36384703
DOI: 10.1183/16000617.0105-2022 -
Human Vaccines & Immunotherapeutics Aug 2023Human papillomavirus (HPV) vaccines work by preventing infections prior to natural exposure. Thus, it is likely more effective at younger ages, and it is important to... (Review)
Review
Human papillomavirus (HPV) vaccines work by preventing infections prior to natural exposure. Thus, it is likely more effective at younger ages, and it is important to understand how effectiveness might be diminished when administered at older ages. We conducted a systematic review of HPV vaccine effectiveness studies published between 2007 and 2022 that included an analysis of effectiveness against vaccine-type HPV infections, anogenital warts, cervical abnormalities and cervical cancer by age at vaccine initiation or completion. Searching multiple databases, 21 studies were included and results were summarized descriptively. Seventeen studies found the highest vaccine effectiveness in the youngest age group. Vaccine effectiveness estimates for younger adolescents ages 9-14 years ranged from approximately 74% to 93% and from 12% to 90% for adolescents ages 15-18 years. These results demonstrate that the HPV vaccine is most effective against HPV-related disease outcomes when given at younger ages, emphasizing the importance of on-time vaccination.
Topics: Female; Adolescent; Humans; Papillomavirus Vaccines; Papillomavirus Infections; Human Papillomavirus Viruses; Vaccine Efficacy; Uterine Cervical Neoplasms; Vaccination
PubMed: 37529935
DOI: 10.1080/21645515.2023.2239085 -
Parasitology Dec 2021Ascariasis is the most prevalent helminth infection in the world and leads to significant, life-long morbidity, particularly in young children. Current efforts to...
Ascariasis is the most prevalent helminth infection in the world and leads to significant, life-long morbidity, particularly in young children. Current efforts to control and eradicate ascariasis in endemic regions have been met with significant challenges including high-rates of re-infection and potential development of anthelminthic drug resistance. Vaccines against ascariasis are a key tool that could break the transmission cycle and lead to disease eradication globally. Evolution of the vaccine pipeline has progressed, however no vaccine product has been brought to human clinical trials to date. Advancement in recombinant protein technology may provide the first step in generating an vaccine as well as a pan-helminthic vaccine ready for human trials. However, several roadblocks remain and investment in new technologies will be important to develop a successful human vaccine that is critically needed to prevent significant morbidity in -endemic regions around the world.
Topics: Animals; Ascariasis; Ascaris; Humans; Vaccine Development; Vaccines
PubMed: 35586777
DOI: 10.1017/s0031182021001347 -
The Lancet. Healthy Longevity Apr 2022Given the substantial impact of herpes zoster on health and quality of life, and its considerable economic burden, prevention through vaccination is a priority. We aimed... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Given the substantial impact of herpes zoster on health and quality of life, and its considerable economic burden, prevention through vaccination is a priority. We aimed to evaluate the effectiveness of the herpes zoster vaccines (recombinant zoster vaccine [RZV] and zoster vaccine live [ZVL]) against incident herpes zoster and postherpetic neuralgia in older adults.
METHODS
We did a systematic review and meta-analysis of studies assessing the effectiveness of herpes zoster vaccines in adults aged 50 years or older, compared with no vaccination or another vaccine. We searched published literature on MEDLINE, Embase, Cochrane Library, Cumulative Index to Nursing and Allied Health Literature, ProQuest Central, and Dimensions, as well as unpublished studies, grey literature, and the reference lists of included studies. Observational studies published in any language between May 25, 2006, and Dec 31, 2020, were included. Eligible studies were appraised for methodological quality using standardised critical appraisal instruments from the Joanna Briggs Institute, and data were extracted from selected studies using a standardised tool. Random-effects meta-analysis models were used to estimate pooled vaccine effectiveness for outcomes of interest (herpes zoster, herpes zoster ophthalmicus, and postherpetic neuralgia) among clinically and methodologically comparable studies, with a fixed-effects model also used for herpes zoster ophthalmicus. Vaccine effectiveness was also assessed in people with comorbidities. As a post-hoc analysis, a forward citation search was done on Jan 31, 2021. This study is registered on PROSPERO, CRD42021232383.
FINDINGS
Our search identified 1240 studies, of which 1162 were excluded based on title and abstract screening. A further 56 articles were excluded on reading the full text. 22 studies (21 cohort studies and one case-control study, involving 9 536 086 participants and 3·35 million person-years in the USA, UK, Canada, and Sweden) were included in the quantitative analysis. Of these, 13 articles were included in the meta-analysis. The overall quality of evidence was very low for all outcomes. The pooled vaccine effectiveness for ZVL against herpes zoster in adults was 45·9% (95% CI 42·2-49·4; seven studies). The vaccine effectiveness for ZVL against postherpetic neuralgia was 59·7% (58·4-89·7; three studies) and against herpes zoster ophthalmicus (in a fixed-effects model) was 30·0% (20·5-38·4; two studies). ZVL was effective in preventing herpes zoster in people with comorbidities, including diabetes (vaccine effectiveness 49·8%, 45·1-54·1; three studies), chronic kidney disease (54·3%, 49·0-59·1; four studies), liver disease (52·9%, 41·6-62·1; two studies), heart disease (52·3%, 45·0-58·7; two studies), and lung disease (49·0%, 32·2-66·2; two studies). In a post-hoc analysis of two studies from the USA published after 2020, the pooled vaccine effectiveness for RZV against herpes zoster in adults was 79·2% (57·6-89·7). Substantial heterogeneity (I≥75%) was observed in 50% of the meta-analyses.
INTERPRETATION
ZVL and RZV are effective in preventing herpes zoster in routine clinical practice. ZVL also reduces the risk of postherpetic neuralgia. Selection bias and confounding by unmeasured variables are inherent challenges of observational studies based on large health-care databases. Nevertheless, these findings will reassure policy makers, health practitioners, and the public that the vaccinations currently available for herpes zoster vaccination programmes are effective at preventing herpes zoster and related complications.
FUNDING
None.
Topics: Aged; Case-Control Studies; Herpes Zoster Ophthalmicus; Herpes Zoster Vaccine; Herpesvirus 3, Human; Humans; Neuralgia, Postherpetic; Quality of Life; Vaccine Efficacy; Vaccines, Synthetic
PubMed: 36098300
DOI: 10.1016/S2666-7568(22)00039-3 -
Vaccine Aug 2015The purpose of this systematic review is to identify, describe and assess the potential effectiveness of strategies to respond to issues of vaccine hesitancy that have... (Review)
Review
UNLABELLED
The purpose of this systematic review is to identify, describe and assess the potential effectiveness of strategies to respond to issues of vaccine hesitancy that have been implemented and evaluated across diverse global contexts.
METHODS
A systematic review of peer reviewed (January 2007-October 2013) and grey literature (up to October 2013) was conducted using a broad search strategy, built to capture multiple dimensions of public trust, confidence and hesitancy concerning vaccines. This search strategy was applied and adapted across several databases and organizational websites. Descriptive analyses were undertaken for 166 (peer reviewed) and 15 (grey literature) evaluation studies. In addition, the quality of evidence relating to a series of PICO (population, intervention, comparison/control, outcomes) questions defined by the SAGE Working Group on Vaccine Hesitancy (WG) was assessed using Grading of Recommendations Assessment, Development and Evaluation (GRADE) criteria; data were analyzed using Review Manager.
RESULTS
Across the literature, few strategies to address vaccine hesitancy were found to have been evaluated for impact on either vaccination uptake and/or changes in knowledge, awareness or attitude (only 14% of peer reviewed and 25% of grey literature). The majority of evaluation studies were based in the Americas and primarily focused on influenza, human papillomavirus (HPV) and childhood vaccines. In low- and middle-income regions, the focus was on diphtheria, tetanus and pertussis, and polio. Across all regions, most interventions were multi-component and the majority of strategies focused on raising knowledge and awareness. Thirteen relevant studies were used for the GRADE assessment that indicated evidence of moderate quality for the use of social mobilization, mass media, communication tool-based training for health-care workers, non-financial incentives and reminder/recall-based interventions. Overall, our results showed that multicomponent and dialogue-based interventions were most effective. However, given the complexity of vaccine hesitancy and the limited evidence available on how it can be addressed, identified strategies should be carefully tailored according to the target population, their reasons for hesitancy, and the specific context.
Topics: Communication; Health Knowledge, Attitudes, Practice; Health Personnel; Humans; Patient Acceptance of Health Care; Patient Compliance; Treatment Refusal; Vaccination; Vaccines; World Health Organization
PubMed: 25896377
DOI: 10.1016/j.vaccine.2015.04.040 -
Journal of Medical Internet Research Aug 2022The development of COVID-19 vaccines has been crucial in fighting the pandemic. However, misinformation about the COVID-19 pandemic and vaccines is spread on social... (Review)
Review
BACKGROUND
The development of COVID-19 vaccines has been crucial in fighting the pandemic. However, misinformation about the COVID-19 pandemic and vaccines is spread on social media platforms at a rate that has made the World Health Organization coin the phrase infodemic. False claims about adverse vaccine side effects, such as vaccines being the cause of autism, were already considered a threat to global health before the outbreak of COVID-19.
OBJECTIVE
We aimed to synthesize the existing research on misinformation about COVID-19 vaccines spread on social media platforms and its effects. The secondary aim was to gain insight and gather knowledge about whether misinformation about autism and COVID-19 vaccines is being spread on social media platforms.
METHODS
We performed a literature search on September 9, 2021, and searched PubMed, PsycINFO, ERIC, EMBASE, Cochrane Library, and the Cochrane COVID-19 Study Register. We included publications in peer-reviewed journals that fulfilled the following criteria: original empirical studies, studies that assessed social media and misinformation, and studies about COVID-19 vaccines. Thematic analysis was used to identify the patterns (themes) of misinformation. Narrative qualitative synthesis was undertaken with the guidance of the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) 2020 Statement and the Synthesis Without Meta-analysis reporting guideline. The risk of bias was assessed using the Joanna Briggs Institute Critical Appraisal tool. Ratings of the certainty of evidence were based on recommendations from the Grading of Recommendations Assessment, Development and Evaluation Working Group.
RESULTS
The search yielded 757 records, with 45 articles selected for this review. We identified 3 main themes of misinformation: medical misinformation, vaccine development, and conspiracies. Twitter was the most studied social media platform, followed by Facebook, YouTube, and Instagram. A vast majority of studies were from industrialized Western countries. We identified 19 studies in which the effect of social media misinformation on vaccine hesitancy was measured or discussed. These studies implied that the misinformation spread on social media had a negative effect on vaccine hesitancy and uptake. Only 1 study contained misinformation about autism as a side effect of COVID-19 vaccines.
CONCLUSIONS
To prevent these misconceptions from taking hold, health authorities should openly address and discuss these false claims with both cultural and religious awareness in mind. Our review showed that there is a need to examine the effect of social media misinformation on vaccine hesitancy with a more robust experimental design. Furthermore, this review also demonstrated that more studies are needed from the Global South and on social media platforms other than the major platforms such as Twitter and Facebook.
TRIAL REGISTRATION
PROSPERO International Prospective Register of Systematic Reviews CRD42021277524; https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021277524.
INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)
RR2-10.31219/osf.io/tyevj.
Topics: COVID-19; COVID-19 Vaccines; Communication; Humans; Pandemics; Social Media; Vaccines
PubMed: 35816685
DOI: 10.2196/37367 -
BMC Infectious Diseases Aug 2019Dengue is an arbovirus that has rapidly spread worldwide, and the incidence of dengue has greatly increased in recent decades. The actual numbers of dengue cases are... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Dengue is an arbovirus that has rapidly spread worldwide, and the incidence of dengue has greatly increased in recent decades. The actual numbers of dengue cases are underreported, and many cases are not classified correctly. Recent estimates indicate that 390 million dengue infections occur per year (95% CI, 284-528 million), of which 96 million (67-136 million) are symptomatic infections of any severity. One of the goals of the World Health Organization is to reduce dengue mortality by 50% by the year 2020. The use of a vaccine can be an important strategy to achieve this goal. Vaccines for dengue are in various stages of development; in Brazil, only one commercial formulation is available (CYD-TDV), which was developed by Sanofi Pasteur.
METHODS
To evaluate the efficacy of Dengue vaccine, a systematic review with a meta-analysis was conducted using randomized controlled clinical trials published between 2000 and 2017 that were identified in the MEDLINE databases via PubMed, LILACS, Cochrane Library, and EMBASE. The selection was performed by two reviewers independently, with disagreements resolved by a third reviewer.
RESULTS
Seven clinical trials were included, with a total of 36,371 participants (66,511 person-years) between the ages of 2 and 45 years. The meta-analysis using the random-effects model estimated the efficacy of the vaccine at 44%, with a range from 25 to 59% and high heterogeneity (I = 80.1%). The serotype-stratified meta-analysis was homogeneous, except for serotype 2, with the heterogeneity of 64.5%. Most of the vaccinated individuals had previous immunity for at least one serotype, which generated safety concerns in individuals without previous immunity.
CONCLUSIONS
Compared with other commercially available vaccines, the dengue vaccine showed poor efficacy.
Topics: Adolescent; Adult; Brazil; Child; Child, Preschool; Dengue; Dengue Vaccines; Humans; Middle Aged; Randomized Controlled Trials as Topic; Serogroup
PubMed: 31455279
DOI: 10.1186/s12879-019-4369-5 -
Reviews in Medical Virology May 2019Cytomegalovirus (CMV) infection does not usually produce symptoms when it causes primary infection, reinfection, or reactivation because these three types of infection... (Meta-Analysis)
Meta-Analysis
Cytomegalovirus (CMV) infection does not usually produce symptoms when it causes primary infection, reinfection, or reactivation because these three types of infection are all controlled by the normal immune system. However, CMV becomes an important pathogen in individuals whose immune system is immature or compromised, such as the unborn child. Several vaccines against CMV are currently in clinical trials that aim to induce immunity in seronegative individuals and/or to boost the immunity of those with prior natural infection (seropositives). To facilitate estimation of the burden of disease and the need for vaccines that induce de novo immune responses or that boost pre-existing immunity to CMV, we conducted a systematic survey of the published literature to describe the global seroprevalence of CMV IgG antibodies. We estimated a global CMV seroprevalence of 83% (95%UI: 78-88) in the general population, 86% (95%UI: 83-89) in women of childbearing age, and 86% (95%UI: 82-89) in donors of blood or organs. For each of these three groups, the highest seroprevalence was seen in the World Health Organisation (WHO) Eastern Mediterranean region 90% (95%UI: 85-94) and the lowest in WHO European region 66% (95%UI: 56-74). These estimates of the worldwide CMV distribution will help develop national and regional burden of disease models and inform future vaccine development efforts.
Topics: Antibodies, Viral; Cytomegalovirus; Cytomegalovirus Infections; Global Health; Humans; Immunoglobulin G; Seroepidemiologic Studies
PubMed: 30706584
DOI: 10.1002/rmv.2034 -
Public Health Nov 2023Dengue is the most important human vector-borne disease in terms of disease burden. A first dengue vaccine has recently been licenced, and others are in advanced stages... (Meta-Analysis)
Meta-Analysis Review
OBJECTIVE
Dengue is the most important human vector-borne disease in terms of disease burden. A first dengue vaccine has recently been licenced, and others are in advanced stages of development. However, to date, none of these vaccines has achieved balanced efficacy and safety for all dengue serotypes. The aim of this systematic review and meta-analysis was to assess the global acceptance and willingness to pay for unspecified dengue vaccines.
METHODS
This systematic review and meta-analysis included cross-sectional and cohort studies that reported values for vaccine acceptance (percentage) and willingness to pay for currently available or hypothetical vaccines. These values were pooled using random-effects models for the acceptance, while weighted linear regression was chosen for willingness to pay. Heterogeneity between studies was assessed using prediction intervals (PIs), and a domain-based tool was used to assess the risk of bias. Subgroup and sensitivity analyses were performed where appropriate. This study was registered with PROSPERO (CRD42021255784).
RESULTS
We included 19 studies from the Americas and Asia in the quantitative meta-analysis. The risk of bias was mainly related to the selection of participants and to the assumptions about the safety and efficacy of the vaccines. The percentage of vaccine acceptance was 88.3% (95% CI: 81.0%-93.0%), with some heterogeneity between studies (80% PI: 52.9%-98.1%). Willingness to pay was US$ 46.7 (95% CI: 25.9-67.5) per vaccine recipient. There were differences between continents, with higher acceptance in the Americas.
CONCLUSIONS
We were able to obtain global estimates of vaccine acceptance and willingness to pay and identify the associated factors that influence these values. This knowledge is relevant for the planning of future vaccination strategies.
Topics: Humans; Dengue Vaccines; Dengue; Patient Acceptance of Health Care; Vaccination Hesitancy
PubMed: 37741155
DOI: 10.1016/j.puhe.2023.08.022