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Global Health Research and Policy Nov 2022COVID-19 vaccination has been advocated as the most effective way to curb the pandemic. But with its inequitable distribution and slow rollout, especially in low- to... (Review)
Review
BACKGROUND
COVID-19 vaccination has been advocated as the most effective way to curb the pandemic. But with its inequitable distribution and slow rollout, especially in low- to middle- income countries, it will still take a long time before herd immunity is achieved. Alternative measures must therefore be explored to bolster current COVID-19 vaccination efforts. In particular, the Bacille Calmette-Guerin vaccine has been studied extensively as to its proposed conferment of non-specific immunity against different infections, including COVID-19. The aim of this study, therefore, is to evaluate the current evidence on the effectiveness of national BCG vaccination policies in reducing infection and mortality of COVID-19.
METHODS
A systematic review was conducted between April to August 2021 following the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA-P) guidelines. Literature was retrieved from PubMed, Cochrane, HERDIN, Web of Science, EBSCO, and Western Pacific Region Index Medicus (WPRIM). Studies conducted from January 2020 to August 2021 that fell within Level 1A to 2C of the Oxford Center for Evidence-Based Medicine were included in the review. Quality assessment was performed using the appropriate Joanna Briggs Institute critical appraisal tool and a quality assessment checklist for ecological studies adapted from Betran et al. RESULTS: A total of 13 studies were included in this review. Nine studies reported significant association between BCG vaccination policies and COVID-19 outcomes, even when controlling for confounding variables. In addition, among other mandated vaccines, such as pneumococcal, influenza, diphtheria-tetanus-pertussis, and measles, only BCG vaccination showed significant association with decreased COVID-19 adverse outcomes. However, other factors also showed positive association with COVID-19 outcomes, particularly markers of high economic status of countries, higher median age, and greater population densities.
CONCLUSION
The lower incidence and mortality of COVID-19 in countries with mandated BCG vaccination may not solely be attributable to BCG vaccination policies, but there is still some evidence that demonstrates a possible protective effect. Clinical trials must be continued before recommendations of BCG vaccinations are to be used as an alternative or booster vaccine against COVID-19.
Topics: Humans; BCG Vaccine; COVID-19; COVID-19 Vaccines; Policy; Vaccination
PubMed: 36336688
DOI: 10.1186/s41256-022-00275-x -
Microorganisms Apr 2024(1) Background: We aim to systematically review the current evidence on immunity against tetanus, diphtheria, and pertussis in adult solid organ transplantation (SOT)... (Review)
Review
(1) Background: We aim to systematically review the current evidence on immunity against tetanus, diphtheria, and pertussis in adult solid organ transplantation (SOT) recipients, either through natural infection or vaccination. (2) Methods: This systematic review was conducted per PRISMA guidelines. We assessed the risk of bias using the Cochrane RoB 2 and ROBINS-I and summarized the findings narratively due to the heterogeneity of the studies. (3) Results: Of the 315 screened articles, 11 were included. Tetanus immunity varied between 55% and 86%, diphtheria immunity from 23% to 75%, and pertussis immunity was between 46% and 82%. Post-vaccination immunity showed variation across the studies, with some indicating reductions and others no change, with antibody responses influenced by transplanted organs, gender, age, and immunosuppressive regimens. The single randomized study exhibited a low risk of bias, while of the ten non-randomized studies, six showed moderate and four serious risks of bias, necessitating cautious interpretation of results. (4) Conclusions: SOT recipients exhibit considerable immunity against tetanus and diphtheria at transplantation, but this immunity decreases over time. Although vaccination can enhance this immunity, the response may be suboptimal, and the increased antibody levels may not persist, underscoring the need for tailored vaccination strategies in this vulnerable population.
PubMed: 38792678
DOI: 10.3390/microorganisms12050847 -
Human Vaccines & Immunotherapeutics Nov 2022Although the burden of diphtheria has declined greatly since the introduction of vaccines, sporadic outbreaks continue to be reported. WHO recommends booster doses after...
Waning rate of immunity and duration of protective immunity against diphtheria toxoid as a function of age and number of doses: Systematic review and quantitative data analysis.
Although the burden of diphtheria has declined greatly since the introduction of vaccines, sporadic outbreaks continue to be reported. WHO recommends booster doses after a primary series, but questions remain about the optimal interval between these doses. We conducted a systematic review and quantitative data analysis to quantify the duration of protective immunity after different numbers of doses. Fifteen cross-sectional seroprevalence studies provided data on geometric mean concentration (GMC). Single-year age-stratified GMCs were analyzed using a mixed-effect linear regression model with a random intercept incorporating the between-country variability. GMC was estimated to decline to 0.1 IU/ml in 2.5 years (95% CI: 0.9-4.0), 10.3 years (95% CI: 7.1-13.6), and 25.1 years (95% CI: 7.6-42.6) after receiving three, four and five doses, respectively. The results drawn from cross-sectional data collected in countries with different epidemiologies, vaccines, and schedules had several limitations. However, these analyses contribute to the discussion of optimal timing between booster doses of diphtheria toxoid-containing vaccine.
Topics: Humans; Diphtheria-Tetanus-Pertussis Vaccine; Seroepidemiologic Studies; Cross-Sectional Studies; Diphtheria Toxoid; Diphtheria; Data Analysis; Antibodies, Bacterial; Immunization, Secondary
PubMed: 35862651
DOI: 10.1080/21645515.2022.2099700 -
Frontiers in Microbiology 2024The Vi-diphtheria toxoid typhoid conjugate vaccine (Vi-DT) has shown promising results in preventing typhoid fever in children under 2 years of age. However, a thorough...
BACKGROUND
The Vi-diphtheria toxoid typhoid conjugate vaccine (Vi-DT) has shown promising results in preventing typhoid fever in children under 2 years of age. However, a thorough assessment of its safety and immunogenicity is required to inform vaccination strategies. This systematic review and meta-analysis aimed to determine the safety and immunogenicity of Vi-DT in children below 2 years.
METHODS
We systematically searched multiple databases, including PubMed, Web of Science, and Scopus, for relevant studies published up to September 2023. We included studies reporting on the safety and immunogenicity outcomes of Vi-DT compared to the control or Vi-tetanus toxoid conjugated vaccine (Vi-TT) in children below 2 years. We applied a random-effects model for meta-analysis using RevMan 5.4. We expressed the results as risk ratio (RR) with a 95% confidence interval (95%CI).
RESULTS
In this analysis, five studies were selected, encompassing 1,292 children under 2 years who received the Vi-DT vaccine. No significant difference in immediate reactions was observed within 30 min post-vaccination between Vi-DT and control groups (RR: 0.99 [95% CI: 0.19, 5.26]), nor between Vi-DT and Vi-TT groups. For solicited adverse events within 4 weeks, the VI-DT group showed no significant increase in adverse events compared to control (RR: 0.93 [95% CI: 0.78, 1.12]) or Vi-TT (RR: 0.86 [95% CI: 0.69, 1.07]). Similarly, within 7 days post-vaccination, risk ratios indicated no significant differences in adverse events between the groups. The 4-week seroconversion rate was significantly higher in the Vi-DT group compared to the control (RR: 1.99 [95% CI: 1.07, 3.69]), but no difference was found between Vi-DT and Vi-TT. Adverse events associated with typhoid conjugate vaccines were predominantly non-serious, including fever and injection site reactions. Serious adverse events were rare but included conditions like pneumonia and gastroenteritis.
CONCLUSION
This meta-analysis highlights Vi-DT safety and immunogenicity in six to 24-month-old children. The findings support the use of this Vi-DT to expand typhoid vaccination in endemic regions, in line with WHO's strategy.
PubMed: 38646637
DOI: 10.3389/fmicb.2024.1385834 -
Clinical and Experimental Vaccine... Jul 2020Vaccines are credited with reducing or effectively eradicating a number of infectious diseases such as smallpox, measles, and diphtheria. Particularly in nations like... (Review)
Review
Vaccines are credited with reducing or effectively eradicating a number of infectious diseases such as smallpox, measles, and diphtheria. Particularly in nations like the United States, where a large number of infectious diseases were prevalent, vaccines proved to be timely interventions. The approval procedure for vaccines in the United States is regulated by the Center for Biologics Evaluation and Research. Vaccine development is often found to be demanding and requires astute knowledge and understanding of recent developments by physicians and researchers to ensure that effective vaccines are made available to the masses with minimum risk. This article aims to illustrate the regulatory scenario with regards to vaccine development and licensure in the United States with a brief look at the origin of vaccines and their regulations in the nation. Also, it details the challenges faced by the United States vaccine industry to remain relevant in today's constantly evolving world.
PubMed: 32864362
DOI: 10.7774/cevr.2020.9.2.69 -
Journal of Medical Internet Research Dec 2023Vaccination programs are instrumental in prolonging and improving people's lives by preventing diseases such as measles, diphtheria, tetanus, pertussis, and influenza... (Review)
Review
BACKGROUND
Vaccination programs are instrumental in prolonging and improving people's lives by preventing diseases such as measles, diphtheria, tetanus, pertussis, and influenza from escalating into fatal epidemics. Despite the significant impact of these programs, a substantial number of individuals, including 20 million infants annually, lack sufficient access to vaccines. Therefore, it is imperative to raise awareness about vaccination programs.
OBJECTIVE
This study aims to investigate the potential utilization of social media, assessing its scalability and robustness in delivering accurate and reliable information to individuals who are contemplating vaccination decisions for themselves or on behalf of their children.
METHODS
The protocol for this review is registered in PROSPERO (identifier CRD42022304229) and is being carried out in compliance with the Cochrane Handbook for Systematic Reviews of Interventions. Comprehensive searches have been conducted in databases including MEDLINE, Embase, PsycINFO, CINAHL (Cumulative Index to Nursing and Allied Health), CENTRAL (Cochrane Central Register of Controlled Trials), and Google Scholar. Only randomized controlled trials (RCTs) were deemed eligible for inclusion in this study. The target population encompasses the general public, including adults, children, and adolescents. The defined interventions comprise platforms facilitating 2-way communication for sharing information. These interventions were compared against traditional interventions and teaching methods, referred to as the control group. The outcomes assessed in the included studies encompassed days unvaccinated, vaccine acceptance, and the uptake of vaccines compared with baseline. The studies underwent a risk-of-bias assessment utilizing the Cochrane Risk-of-Bias tool for RCTs, and the certainty of evidence was evaluated using the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) assessment.
RESULTS
This review included 10 studies, detailed in 12 articles published between 2012 and 2022, conducted in the United States, China, Jordan, Australia, and Israel. The studies involved platforms such as Facebook, Twitter, WhatsApp, and non-general-purpose social media. The outcomes examined in these studies focused on the uptake of vaccines compared with baseline, vaccine acceptance, and the number of days individuals remained unvaccinated. The overall sample size for this review was 26,286, with individual studies ranging from 58 to 21,592 participants. The effect direction plot derived from articles of good and fair quality indicated a nonsignificant outcome (P=.12).
CONCLUSIONS
The findings suggest that, in a real-world scenario, an equal number of positive and negative results may be expected due to the interventions' impact on the acceptance and uptake of vaccines. Nevertheless, there is a rationale for accumulating experience to optimize the use of social media with the aim of enhancing vaccination rates. Social media can serve as a tool with the potential to disseminate information and boost vaccination rates within a population. However, relying solely on social media is not sufficient, given the complex structures at play in vaccine acceptance. Effectiveness hinges on various factors working in tandem. It is crucial that authorized personnel closely monitor and moderate discussions on social media to ensure responsible and accurate information dissemination.
Topics: Adolescent; Adult; Child; Humans; Infant; Australia; Influenza Vaccines; Randomized Controlled Trials as Topic; Social Media; Systematic Reviews as Topic; Vaccination
PubMed: 38147375
DOI: 10.2196/50276 -
Expert Review of Vaccines Jul 2021Pertussis is a highly contagious respiratory disease that results in disproportionate morbidity and mortality in infants who have yet to receive the primary...
INTRODUCTION
Pertussis is a highly contagious respiratory disease that results in disproportionate morbidity and mortality in infants who have yet to receive the primary diphtheria-tetanus-pertussis vaccine series. In the preceding decades numerous countries began to pursue either prenatal vaccination of pregnant women or postpartum vaccination of caregivers to protect infants. Despite proven benefit, maternal uptake of pertussis vaccine continues to remain suboptimal.
AREAS COVERED
Many studies have been conducted to address the suboptimal uptake of maternal pertussis vaccination. This systematic review was undertaken to systematically identify those studies, highlight the most successful strategies and find the knowledge gaps that need to be filled over the coming years to improve vaccine uptake. Twenty-five studies were identified from six different databases.
EXPERT OPINION
Five different interventions were shown to be successful in promoting uptake of pertussis vaccination: (1) standing orders, (2) opt-in orders, (3) provider education, (4) on-site vaccination and (5) interactive patient education. Three major knowledge gaps were also identified that need to be filled over the coming years: (1) lack of studies in low- and middle-income countries, (2) lack of studies targeting midwives and/or home birth and (3) lack of studies on the process of vaccine communication.
Topics: Diphtheria-Tetanus-Pertussis Vaccine; Diphtheria-Tetanus-acellular Pertussis Vaccines; Female; Humans; Infant; Pertussis Vaccine; Pregnancy; Vaccination; Whooping Cough
PubMed: 34129416
DOI: 10.1080/14760584.2021.1940146 -
PloS One 2024Nigeria has a high proportion of the world's underimmunised children. We estimated the inequities in childhood immunisation coverage associated with socioeconomic,...
Systematic review of social determinants of childhood immunisation in low- and middle-income countries and equity impact analysis of childhood vaccination coverage in Nigeria.
BACKGROUND
Nigeria has a high proportion of the world's underimmunised children. We estimated the inequities in childhood immunisation coverage associated with socioeconomic, geographic, maternal, child, and healthcare characteristics among children aged 12-23 months in Nigeria using a social determinants of health perspective.
METHODS
We conducted a systematic review to identify the social determinants of childhood immunisation associated with inequities in vaccination coverage among low- and middle-income countries. Using the 2018 Nigeria Demographic and Health Survey (DHS), we conducted multiple logistic regression to estimate the association between basic childhood vaccination coverage (1-dose BCG, 3-dose DTP-HepB-Hib (diphtheria, tetanus, pertussis, hepatitis B and Haemophilus influenzae type B), 3-dose polio, and 1-dose measles) and socioeconomic, geographic, maternal, child, and healthcare characteristics in Nigeria.
RESULTS
From the systematic review, we identified the key determinants of immunisation to be household wealth, religion, and ethnicity for socioeconomic characteristics; region and place of residence for geographic characteristics; maternal age at birth, maternal education, and household head status for maternal characteristics; sex of child and birth order for child characteristics; and antenatal care and birth setting for healthcare characteristics. Based of the 2018 Nigeria DHS analysis of 6,059 children aged 12-23 months, we estimated that basic vaccination coverage was 31% (95% CI: 29-33) among children aged 12-23 months, whilst 19% (95% CI:18-21) of them were zero-dose children who had received none of the basic vaccines. After controlling for background characteristics, there was a significant increase in the odds of basic vaccination by household wealth (AOR: 3.21 (2.06, 5.00), p < 0.001) for the wealthiest quintile compared to the poorest quintile, antenatal care of four or more antenatal care visits compared to no antenatal care (AOR: 2.87 (2.21, 3.72), p < 0.001), delivery in a health facility compared to home births (AOR 1.32 (1.08, 1.61), p = 0.006), relatively older maternal age of 35-49 years compared to 15-19 years (AOR: 2.25 (1.46, 3.49), p < 0.001), and maternal education of secondary or higher education compared to no formal education (AOR: 1.79 (1.39, 2.31), p < 0.001). Children of Fulani ethnicity in comparison to children of Igbo ethnicity had lower odds of receiving basic vaccinations (AOR: 0.51 (0.26, 0.97), p = 0.039).
CONCLUSIONS
Basic vaccination coverage is below target levels for all groups. Children from the poorest households, of Fulani ethnicity, who were born in home settings, and with young mothers with no formal education nor antenatal care, were associated with lower odds of basic vaccination in Nigeria. We recommend a proportionate universalism approach for addressing the immunisation barriers in the National Programme on Immunization of Nigeria.
Topics: Female; Humans; Infant, Newborn; Pregnancy; Developing Countries; Immunization; Nigeria; Social Determinants of Health; Vaccination Coverage; Infant
PubMed: 38446836
DOI: 10.1371/journal.pone.0297326 -
Frontiers in Immunology 2021Current vaccination strategies against pertussis are sub-optimal. Optimal protection against , the causative agent of pertussis, likely requires mucosal immunity....
BACKGROUND
Current vaccination strategies against pertussis are sub-optimal. Optimal protection against , the causative agent of pertussis, likely requires mucosal immunity. Current pertussis vaccines consist of inactivated whole cells or purified antigens thereof, combined with diphtheria and tetanus toxoids. Although they are highly protective against severe pertussis disease, they fail to elicit mucosal immunity. Compared to natural infection, immune responses following immunization are short-lived and fail to prevent bacterial colonization of the upper respiratory tract. To overcome these shortcomings, efforts have been made for decades, and continue to be made, toward the development of mucosal vaccines against pertussis.
OBJECTIVES
In this review we systematically analyzed published literature on protection conferred by mucosal immunization against pertussis. Immune responses mounted by these vaccines are summarized.
METHOD
The PubMed Library database was searched for published studies on mucosal pertussis vaccines. Eligibility criteria included mucosal administration and the evaluation of at least one outcome related to efficacy, immunogenicity and safety.
RESULTS
While over 349 publications were identified by the search, only 63 studies met the eligibility criteria. All eligible studies are included here. Initial attempts of mucosal whole-cell vaccine administration in humans provided promising results, but were not followed up. More recently, diverse vaccination strategies have been tested, including non-replicating and replicating vaccine candidates given by three different mucosal routes: orally, nasally or rectally. Several adjuvants and particulate formulations were tested to enhance the efficacy of non-replicating vaccines administered mucosally. Most novel vaccine candidates were only tested in animal models, mainly mice. Only one novel mucosal vaccine candidate was tested in baboons and in human trials.
CONCLUSION
Three vaccination strategies drew our attention, as they provided protective and durable immunity in the respiratory tract, including the upper respiratory tract: acellular vaccines adjuvanted with lipopeptide LP1569 and c-di-GMP, outer membrane vesicles and the live attenuated BPZE1 vaccine. Among all experimental vaccines, BPZE1 is the only one that has advanced into clinical development.
Topics: Humans; Immunity, Mucosal; Pertussis Vaccine; Whooping Cough
PubMed: 34211481
DOI: 10.3389/fimmu.2021.701285 -
BMC Infectious Diseases Feb 2020Infants < 3 months of age are at highest risk for developing severe complications after pertussis. The majority of pregnant women has low concentrations of...
BACKGROUND
Infants < 3 months of age are at highest risk for developing severe complications after pertussis. The majority of pregnant women has low concentrations of pertussis-specific antibodies and thus newborns are insufficiently protected by maternally transferred antibodies. Acellular pertussis vaccination during pregnancy was recently implemented in various countries. Here, we assessed the evidence for safety and effectiveness of pertussis vaccination during pregnancy.
METHODS
We searched Medline, Embase, and ClinicalTrials.gov from January 1st 2010 to January 10th 2019. We assessed risk of bias (ROB) using the Cochrane ROB tool and ROBINS-I. We evaluated the quality of evidence using the GRADE approach.
RESULTS
We identified 1273 articles and included 22 studies (14 for safety; 8 for effectiveness), comprising 1.4 million pregnant women in safety studies and 855,546 mother-infant-pairs in effectiveness studies. No significant differences between vaccinated and unvaccinated women and their infants were observed for safety outcomes with the exception of fever and chorioamnionitis. Compared to no vaccination, three studies showed a significantly increased relative risk for the presence of the ICD-9 code for chorioamnionitis in electronic patient data after pertussis vaccination. However, no study reported an increased risk for clinical sequelae of chorioamnionitis after vaccination during pregnancy, such as preterm birth or neonatal intensive care unit admission. Vaccine effectiveness against pertussis in infants of immunized mothers ranged from 69 to 91% for pertussis prevention, from 91 to 94% for prevention of hospitalization and was 95% for prevention of death due to pertussis. Risk of bias was serious to critical for safety outcomes and moderate to serious for effectiveness outcomes. GRADE evidence quality was moderate to very low, depending on outcome.
CONCLUSION
Although an increased risk for a diagnosis of fever and chorioamnionitis was detected in pregnant women after pertussis vaccination, there was no association with a higher frequency of clinically relevant sequelae. Vaccine effectiveness for prevention of infant pertussis, hospitalization and death is high. Pertussis vaccination during pregnancy has an overall positive benefit-risk ratio. In view of the overall quality of available evidence ongoing surveillance of chorioamnionitis and its potential sequelae is recommended when pertussis vaccination in pregnancy is implemented.
TRIAL REGISTRATION
PROSPERO CRD42018087814, CRD42018090357.
Topics: Adolescent; Adult; Bordetella pertussis; Child; Chorioamnionitis; Diphtheria-Tetanus-acellular Pertussis Vaccines; Female; Fever; Humans; Infant; Infant, Newborn; Middle Aged; Pregnancy; Pregnant Women; Premature Birth; Risk; Treatment Outcome; Vaccination; Whooping Cough; Young Adult
PubMed: 32054444
DOI: 10.1186/s12879-020-4824-3