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The Lancet. Infectious Diseases Sep 2022Understanding why some migrants in Europe are at risk of underimmunisation and show lower vaccination uptake for routine and COVID-19 vaccines is critical if we are to... (Review)
Review
Understanding why some migrants in Europe are at risk of underimmunisation and show lower vaccination uptake for routine and COVID-19 vaccines is critical if we are to address vaccination inequities and meet the goals of WHO's new Immunisation Agenda 2030. We did a systematic review (PROSPERO: CRD42020219214) exploring barriers and facilitators of vaccine uptake (categorised using the 5As taxonomy: access, awareness, affordability, acceptance, activation) and sociodemographic determinants of undervaccination among migrants in the EU and European Economic Area, the UK, and Switzerland. We searched MEDLINE, CINAHL, and PsycINFO from 2000 to 2021 for primary research, with no restrictions on language. 5259 data sources were screened, with 67 studies included from 16 countries, representing 366 529 migrants. We identified multiple access barriers-including language, literacy, and communication barriers, practical and legal barriers to accessing and delivering vaccination services, and service barriers such as lack of specific guidelines and knowledge of health-care professionals-for key vaccines including measles-mumps-rubella, diphtheria-pertussis-tetanus, human papillomavirus, influenza, polio, and COVID-19 vaccines. Acceptance barriers were mostly reported in eastern European and Muslim migrants for human papillomavirus, measles, and influenza vaccines. We identified 23 significant determinants of undervaccination in migrants (p<0·05), including African origin, recent migration, and being a refugee or asylum seeker. We did not identify a strong overall association with gender or age. Tailored vaccination messaging, community outreach, and behavioural nudges facilitated uptake. Migrants' barriers to accessing health care are already well documented, and this Review confirms their role in limiting vaccine uptake. These findings hold immediate relevance to strengthening vaccination programmes in high-income countries, including for COVID-19, and suggest that tailored, culturally sensitive, and evidence-informed strategies, unambiguous public health messaging, and health system strengthening are needed to address access and acceptance barriers to vaccination in migrants and create opportunities and pathways for offering catch-up vaccinations to migrants.
Topics: COVID-19; COVID-19 Vaccines; Europe; Health Services Accessibility; Humans; Measles; Transients and Migrants; Vaccination; Vaccines
PubMed: 35429463
DOI: 10.1016/S1473-3099(22)00066-4 -
Infectious Diseases and Therapy Sep 2021Cyclic epidemics of pertussis (whooping cough) have been observed globally over the past twenty years despite high infant vaccine coverage. The resurgence of pertussis... (Review)
Review
Cyclic epidemics of pertussis (whooping cough) have been observed globally over the past twenty years despite high infant vaccine coverage. The resurgence of pertussis in high-income countries is partly due to waning vaccine immunity in older children and adults, as well as better surveillance and diagnostics. Moreover, in adolescents and adults, pertussis symptoms are mild and similar to common cough syndromes, meaning that it is under-diagnosed in older populations. A systematic search of MEDLINE, EMBASE, and BIOSIS was undertaken to identify studies published between 1 January 1990 and 17 June 2019, with information on pertussis epidemiology, burden of illness, and mortality in school-aged children, adolescents, and adults in Asia. Studies identified for inclusion were reviewed narratively because a statistical comparison was not possible due to the mix of methodologies used. The results showed that in East Asia, including Japan, South Korea, China, and Taiwan, pertussis is circulating in older children and adults. Diphtheria-tetanus-pertussis (DTP4) coverage is high in East Asia, yet outbreaks observed in Japan and South Korea suggest that vaccine-acquired immunity had waned in adolescents and adults. Several school outbreaks in China show that pertussis is circulating in young children, with continued circulation in adolescents and adults. There was a lack of information from Southeast/South Asian countries, although pan-Asian serosurveys showed that recent pertussis infection was common in adolescents and in adults with persistent cough. To conclude, the circulation of pertussis in Asian countries with high DTP4 coverage supports the expansion of routine vaccination to include booster doses for children at school entry and adolescents. However, surveillance is weak or absent in many countries, meaning that the true burden of pertussis, particularly among older populations, is unknown.
PubMed: 33928533
DOI: 10.1007/s40121-021-00439-1 -
Campbell Systematic Reviews Sep 2022Immunisation is one of the most cost-effective interventions to prevent and control life-threatening infectious diseases. Nonetheless, rates of routine vaccination of... (Review)
Review
Immunisation is one of the most cost-effective interventions to prevent and control life-threatening infectious diseases. Nonetheless, rates of routine vaccination of children in low- and middle-income countries (LMICs) are strikingly low or stagnant. In 2019, an estimated 19.7 million infants did not receive routine immunisations. Community engagement interventions are increasingly being emphasised in international and national policy frameworks as a means to improve immunisation coverage and reach marginalised communities. This systematic review examines the effectiveness and cost-effectiveness of community engagement interventions on outcomes related to childhood immunisation in LMICs and identifies contextual, design and implementation features that may be associated with effectiveness. We identified 61 quantitative and mixed methods impact evaluations and 47 associated qualitative studies related to community engagement interventions for inclusion in the reteview. For cost-effectiveness analysis 14 of the 61 studies had the needed combination of cost and effectiveness data. The 61 included impact evaluations were concentrated in South Asia and Sub-Saharan Africa and spread across 19 LMICs. The review found that community engagement interventions had a small but significant, positive effect on all primary immunisation outcomes related to coverage and their timeliness. The findings are robust to exclusion of studies assessed as high risk of bias. Qualitative evidence indicates appropriate intervention design, including building in community engagement features; addressing common contextual barriers of immunisation and leveraging facilitators; and accounting for existing implementation constraints and practicalities on the ground are consistently cited as reasons for intervention success. Among the studies for which we were able to calculate cost-effectiveness, we find that the median non-vaccine cost per dose of intervention to increase immunisation coverage by 1% was US $3.68. Given the broad scope of the review in terms of interventions and outcomes, there is significant variation in findings. Among the various types of community engagement interventions, those that involve creation of community buy-in or development of new cadres of community-based structures were found to have consistent positive effect on more primary vaccination coverage outcomes than if the engagement is limited to the design or delivery of an intervention or is a combination of the various types. The evidence base for sub-group analysis for female children was sparse (only two studies) and the effect on coverage of both full immunisation and third dose of diphtheria pertussis tetanus for this group was insignificant.
PubMed: 36913200
DOI: 10.1002/cl2.1253 -
Infectious Diseases and Therapy Jun 2021Despite modern diphtheria-tetanus-pertussis (DTP) vaccines and high vaccine coverage, a resurgence of pertussis (whooping cough) has been observed globally. In North... (Review)
Review
Despite modern diphtheria-tetanus-pertussis (DTP) vaccines and high vaccine coverage, a resurgence of pertussis (whooping cough) has been observed globally. In North America and Europe, high vaccine coverage in children has led to a shift in the age-specific peak incidence of infection away from infants and towards older children and adolescents. However, much less is known about the prevalence of pertussis in older children and adults in the Middle East. A systematic search of MEDLINE, EMBASE, and BIOSIS was undertaken to identify studies published between 1 January 1990 and 17 June 2019, with information on pertussis epidemiology, burden of illness, and mortality in school-aged children, adolescents, and adults in the Middle East. Studies identified for inclusion were reviewed narratively because a statistical comparison was not possible because of the mix of methodologies used. The results showed that surveillance data are weak or missing in most Middle Eastern countries, and among 24 epidemiological studies identified, most were from Iran (14), Israel (4), and Turkey (3), with single studies from the United Arab Emirates and Iraq. Despite various surveillance periods, clinical definitions, and antibody cut-off values used across the studies, the reported seroprevalence of pertussis antibodies suggested that adolescents and adults are commonly exposed to pertussis in the community and that vaccine-acquired immunity from childhood wanes. Few countries in the Middle East include a diphtheria-tetanus-acellular pertussis (Tdap) booster for adolescents on the national schedule. Israel was the only country with epidemiological data in a population that received Tdap, and the study showed that after the introduction of the adolescent booster dose, there was decrease in pertussis among children aged 5-14 years. To conclude, results from the Middle East suggest that in common with other regions, pertussis is widely circulating and that it might be shifting towards older age groups.
PubMed: 33905101
DOI: 10.1007/s40121-021-00440-8 -
Revista Panamericana de Salud Publica =... 2017.
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Vaccines Jul 2023COVID-19 caused significant morbidity and mortality amongst ethnic minority groups, but vaccine uptake remained lower than non-minoritised groups. Interventions to... (Review)
Review
COVID-19 caused significant morbidity and mortality amongst ethnic minority groups, but vaccine uptake remained lower than non-minoritised groups. Interventions to increase vaccine uptake among ethnic minority communities are crucial. This systematic review synthesises and evaluates behaviour change techniques (BCTs) in interventions to increase vaccination uptake in ethnic minority populations. We searched five databases and grey literature sources. From 7637 records identified, 23 studies were included in the review. Interventions were categorised using the Behaviour Change Wheel (BCW) and Behaviour Change Taxonomy v1. Vaccines included influenza, pertussis, tetanus, diphtheria, meningitis and hepatitis. Interventions were primarily delivered in health centres/clinics and community settings. Six BCW intervention functions and policy categories and 26 BCTs were identified. The main intervention functions used were education, persuasion and enablement. Overall, effective interventions had multi-components and were tailored to specific populations. No strong evidence was observed to recommend specific interventions, but raising awareness and involvement of community organisations was associated with positive effects. Several strategies are used to increase vaccine uptake among ethnic minority communities; however, these do not address all issues related to low vaccine acceptance. There is a strong need for an increased understanding of addressing vaccine hesitancy among ethnic minority groups.
PubMed: 37515074
DOI: 10.3390/vaccines11071259 -
BMC Pregnancy and Childbirth Nov 2017Worldwide, pertussis remains a major health problem among children. During the recent outbreaks of pertussis, maternal antenatal immunisation was introduced in several... (Review)
Review
BACKGROUND
Worldwide, pertussis remains a major health problem among children. During the recent outbreaks of pertussis, maternal antenatal immunisation was introduced in several industrial countries. This systematic review aimed to synthesize evidence for the efficacy and safety of the pertussis vaccination that was given to pregnant women to protect infants from pertussis infection.
METHODS
We searched literature in the Cochrane Central Register of Controlled Trials, Medline, Embase, and OpenGrey between inception of the various databases and 16 May 2016. The search terms included 'pertussis', 'whooping cough', 'pertussis vaccine,' 'tetanus, diphtheria and pertussis vaccines' and 'pregnancy' and 'perinatal'.
RESULTS
We included 15 articles in this review, which represented 12 study populations, involving a total of 203,835 mother-infant pairs from the US, the UK, Belgium, Israel, and Vietnam. Of the included studies, there were two randomised controlled trials (RCTs) and the rest were observational studies. Existing evidence suggests that vaccinations administered during 19-37 weeks of gestation are associated with significantly increased antibody levels in the blood of both mothers and their newborns at birth compared to placebo or no vaccination. However, there is a lack of robust evidence to suggest whether these increased antibodies can also reduce the incidence of pertussis (one RCT, n = 48, no incidence in either group) and pertussis-related severe complications (one observational study) or mortality (no study) in infants. Meanwhile, there is no evidence of increased risk of serious complications such as stillbirth (e.g. one RCT, n = 103, RR = 0, meaning no case in the vaccine group), or preterm birth (two RCTs, n = 151, RR = 0.86, 95%CI: 0.14-5.21) related to administration of the vaccine during pregnancy.
CONCLUSION
Given that pertussis infection is increasing in many countries and that newborn babies are at greatest risk of developing severe complications from pertussis, maternal vaccination in the later stages of pregnancy should continue to be supported while further research should fill knowledge gaps and strengthen evidence of its efficacy and safety.
Topics: Belgium; Female; Humans; Infant, Newborn; Infectious Disease Transmission, Vertical; Israel; Observational Studies as Topic; Pertussis Vaccine; Pregnancy; Pregnancy Complications, Infectious; Randomized Controlled Trials as Topic; United Kingdom; United States; Vaccination; Vietnam; Whooping Cough
PubMed: 29166874
DOI: 10.1186/s12884-017-1559-2 -
Environment International Feb 2023Epidemiologic studies of serum per- and polyfluoroalkyl substances (PFAS) and antibody response to vaccines have suggested an adverse association, but the consistency... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Epidemiologic studies of serum per- and polyfluoroalkyl substances (PFAS) and antibody response to vaccines have suggested an adverse association, but the consistency and magnitude of this association remain unclear.
OBJECTIVE
The goal of this systematic review was to determine the size of the association between a doubling in perfluoroalkyl substances (PFAS) serum concentration and difference in log antibody concentration following a vaccine, with a focus on five PFAS: perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), perfluorohexane sulfonate (PFHxS), perfluorononanoic acid (PFNA), and perfluorodecanoic acid (PFDA).
DATA SOURCE
We conducted online searches of PubMed and Web of Science through May 17, 2022 and identified 14 eligible reports published from 2012 to 2022.
STUDY ELIGIBILITY CRITERIA, PARTICIPANTS, AND INTERVENTIONS
We included studies conducted in humans, including mother-child pairs, which examined serum PFAS concentration in relation to serum concentration of antibody to a specific antigen following a vaccine.
STUDY APPRAISAL AND SYNTHESIS METHODS
We used the risk of bias assessment for non-randomized studies of exposure and certainty assessment method proposed by Morgan et al. (2019). Using a multilevel meta-regression model, we quantitatively synthesized the data.
RESULTS
The 14 reports represented 13 unique groups of subjects; the frequency of studies of a given antibody was Tetanus (n = 7); followed by Diphtheria (6); Measles (4); Rubella (3); Haemophilus influenzae type b and Influenza A H1N1 (2 each); and Hepatitis A, Hepatitis B, Influenza A H2N3, Influenza B, and Mumps (1 each). There were approximately 4,830 unique participants included in the analyses across the 14 reports. The models of coefficients between antibody concentration and the five principal PFAS showed homogeneity of associations across antibody types for each principal PFAS. In the models with all antibodies treated as one type, evidence of effect modification by life stage was present for PFOA and PFOS, and for consistency, all associations were evaluated for all ages and for children. The summary associations (coefficients for difference in log[antibody concentration] per doubling of serum PFAS) with 95% confidence intervals that excluded zero ("statistical support"), and certainty of evidence ratings were as follows: for PFOA and all antibodies treated as one type in all ages, -0.06 (-0.10, -0.01; moderate) and in children, -0.10 (-0.16, -0.03; moderate); for Diphtheria in children, -0.12 (-0.23, -0.00; high); for Rubella in all ages, -0.09 (-0.17, -0.01; moderate), and for Tetanus in children, -0.12 (-0.24, -0.00; moderate). For PFOS the summary associations were, for all antibodies treated as one type in all ages, -0.06 (-0.11, -0.01; moderate) and in children, -0.10 (-0.18, -0.03; moderate); for Rubella in all ages, -0.09 (-0.15, -0.03; high) and in children, -0.12 (-0.20, -0.04; high). For PFHxS the summary associations were, for all antibodies treated as one type in all ages, -0.03 (-0.06, -0.00; moderate) and in children, -0.05 (-0.09, -0.00; low); and for Rubella in children, -0.07 (-0.11, -0.02; high). Summary associations for PFNA and PFDA did not have statistical support, but all PFAS studied tended to have an inverse association with antibody concentrations.
LIMITATIONS AND CONCLUSIONS
Epidemiologic data on immunosuppression and five principal PFAS suggest an association, with support across antibodies against multiple types of antigens. Data on Diphtheria, Rubella, and Tetanus were more supportive of an association than for other antibodies, and support was greater for associations with PFOA, PFOS, and PFHxS, than for PFNA or PFDA. The data on any specific antibody were scarce. Confounding factors that might account for the relation were not identified. Nearly all studies evaluated were judged to have a low or moderate risk of bias.
Topics: Humans; Infant, Newborn; Infant; Environmental Pollutants; Tetanus; Diphtheria; Influenza A Virus, H1N1 Subtype; Influenza, Human; Fluorocarbons; Vaccines; Alkanesulfonic Acids; Alkanesulfonates; Rubella
PubMed: 36764183
DOI: 10.1016/j.envint.2023.107734 -
Vaccines Dec 2019The growing number of available vaccines that can be potentially co-administered makes the assessment of the safety of vaccine co-administration increasingly relevant... (Review)
Review
The growing number of available vaccines that can be potentially co-administered makes the assessment of the safety of vaccine co-administration increasingly relevant but complex. We aimed to synthesize the available scientific evidence on the safety of vaccine co-administrations in children by performing a systematic literature review of studies assessing the safety of vaccine co-administrations in children between 1999 and 2019, in line with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Fifty studies compared co-administered vaccines versus the same vaccines administered separately. The most frequently studied vaccines included quadrivalent meningococcal conjugate (MenACWY) vaccine, diphtheria and tetanus toxoids and acellular pertussis (DTaP) or tetanus toxoid, reduced diphtheria toxoid and acellular pertussis (Tdap) vaccines, diphtheria and tetanus toxoids and acellular pertussis adsorbed, hepatitis B, inactivated poliovirus and type b conjugate (DTaP-HepB-IPV/Hib) vaccine, measles, mumps, and rubella (MMR) vaccine, and pneumococcal conjugate 7-valent (PCV7) or 13-valent (PCV13) vaccines. Of this, 16% (n = 8) of the studies reported significantly more adverse events following immunization (AEFI) while in 10% (n = 5) significantly fewer adverse events were found in the co-administration groups. Statistically significant differences between co-administration and separate administration were found for 16 adverse events, for 11 different vaccine co-administrations. In general, studies briefly described safety and one-third of studies lacked any statistical assessment of AEFI. Overall, the evidence on the safety of vaccine co-administrations compared to separate vaccine administrations is inconclusive and there is a paucity of large post-licensure studies addressing this issue.
PubMed: 31906218
DOI: 10.3390/vaccines8010012 -
The Cochrane Database of Systematic... Jul 2015Tetanus is an acute, often fatal, disease caused by an exotoxin produced by Clostridium tetani. It occurs in newborn infants born to mothers who do not have sufficient... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Tetanus is an acute, often fatal, disease caused by an exotoxin produced by Clostridium tetani. It occurs in newborn infants born to mothers who do not have sufficient circulating antibodies to protect the infant passively, by transplacental transfer. Prevention may be possible by the vaccination of pregnant or non-pregnant women, or both, with tetanus toxoid, and the provision of clean delivery services. Tetanus toxoid consists of a formaldehyde-treated toxin that stimulates the production of antitoxin.
OBJECTIVES
To assess the effectiveness of tetanus toxoid, administered to women of reproductive age or pregnant women, to prevent cases of, and deaths from, neonatal tetanus.
SEARCH METHODS
We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 January 2015), CENTRAL (The Cochrane Library 2015, Issue 1), PubMed (1966 to 28 January 2015), EMBASE (1974 to 28 January 2015) and reference lists of retrieved studies.
SELECTION CRITERIA
Randomised or quasi-randomised trials evaluating the effects of tetanus toxoid in pregnant women or women of reproductive age on numbers of neonatal tetanus cases and deaths.
DATA COLLECTION AND ANALYSIS
Two review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy.
MAIN RESULTS
Two effectiveness trials (9823 infants) and one safety trial (48 mothers) were included. The main outcomes were measured on infants born to a subset of those randomised women who became pregnant during the course of the studies. For our primary outcomes, there was no high-quality evidence according to GRADE assessments.One study (1182 infants) assessed the effectiveness of tetanus toxoid in comparison with influenza vaccine in preventing neonatal tetanus deaths. A single dose did not provide significant protection against neonatal tetanus deaths, (risk ratio (RR) 0.57, 95% confidence interval (CI) 0.26 to 1.24; 494 infants; GRADE: low-quality evidence). However, a two- or three-dose course did provide protection against neonatal deaths, (RR 0.02, 95% CI 0.00 to 0.30; 688 infants; GRADE: moderate-quality evidence). Administration of a two- or three-dose course resulted in significant protection when all causes of death are considered as an outcome (RR 0.31, 95% CI 0.17 to 0.55; 688 infants; GRADE: moderate-quality evidence). No effect was detected on causes of death other than tetanus. Cases of neonatal tetanus after at least one dose of tetanus toxoid were reduced in the tetanus toxoid group, (RR 0.20, 95% CI 0.10 to 0.40; 1182 infants; GRADE: moderate-quality evidence).Another study, involving 8641 children, assessed the effectiveness of tetanus-diphtheria toxoid in comparison with cholera toxoid in preventing neonatal mortality after one or two doses. Neonatal mortality was reduced in the tetanus-diphtheria toxoid group (RR 0.68, 95% CI 0.56 to 0.82). In preventing deaths at four to 14 days, neonatal mortality was reduced again in the tetanus-diphtheria toxoid group (RR 0.38, 95% CI 0.27 to 0.55). The quality of evidence as assessed using GRADE was found to be low.The third small trial assessed that pain at injection site was reported more frequently among pregnant women who received tetanus diphtheria acellular pertussis than placebo (RR 5.68, 95% CI 1.54 to 20.94; GRADE: moderate-quality evidence).
AUTHORS' CONCLUSIONS
Available evidence supports the implementation of immunisation practices on women of reproductive age or pregnant women in communities with similar, or higher, levels of risk of neonatal tetanus, to the two study sites.
Topics: Adult; Cause of Death; Diphtheria-Tetanus Vaccine; Female; Humans; Infant, Newborn; Influenza Vaccines; Pregnancy; Randomized Controlled Trials as Topic; Tetanus; Tetanus Toxoid
PubMed: 26144877
DOI: 10.1002/14651858.CD002959.pub4