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Frontiers in Immunology 2017Dengue hemorrhagic fever is the leading cause of hospitalization and death in children living in Asia and Latin America. There is an urgent need for an effective and... (Review)
Review
BACKGROUND
Dengue hemorrhagic fever is the leading cause of hospitalization and death in children living in Asia and Latin America. There is an urgent need for an effective and safe dengue vaccine to reduce morbidity and mortality in this high-risk population given the lack of dengue specific treatment at present. This review aims to determine the efficacy, safety, and immunogenicity of CYD-TDV vaccine in children.
METHODS
This is a systematic review including meta-analysis of randomized controlled clinical trial data from Embase, Medline, the Cochrane Library, Web of Science, and ClinicalTrials.gov. Studies that assessed CYD-TDV vaccine efficacy [(1 - RR)*100], safety (RR), and immunogenicity (weighted mean difference) in children were included in this study. Random effects model was employed to analyze patient-level data extracted from primary studies.
RESULTS
The overall efficacy of CYD-TDV vaccine was 54% (40-64), while serotype-specific efficacy was 77% (66-85) for DENV4, 75% (65-82) for DENV3, 50% (36-61) for DENV1, and 34% (14-49) for DENV2. 15% (-174-74) vaccine efficacy was obtained for the unknown serotype. Meta-analysis of included studies with longer follow-up time (25 months) revealed that CYD-TDV vaccine significantly increased the risk of injection site reactions (RR = 1.1: 1.04-1.17; -value = 0.001). Immunogenicity (expressed as geometric mean titers) in descending order was 439.7 (331.7-547.7), 323 (247 - 398.7), 144.1 (117.9-170.2), and 105 (88.7-122.8) for DENV3, DENV2, DENV1, and DENV4, respectively.
CONCLUSION
CYD-TDV vaccine is effective and immunogenic in children overall. Reduced efficacy of CYD-TDV vaccine against DENV2 notoriously known for causing severe dengue infection and dengue outbreaks cause for serious concern. meta-analysis of long-term follow-up data (≥25 months) from children previously vaccinated with CYD-TDV vaccine is needed to make a conclusion regarding CYD-TDV vaccine safety in children. However, CYD-TDV vaccine should be considered for use in regions where DENV2 is not endemic as currently there is no specific treatment for dengue infection.
PubMed: 28824613
DOI: 10.3389/fimmu.2017.00863 -
BMJ Open Sep 2023We conducted a systematic review to evaluate associations between influenza vaccination during pregnancy and adverse birth outcomes and maternal non-obstetric serious...
OBJECTIVE
We conducted a systematic review to evaluate associations between influenza vaccination during pregnancy and adverse birth outcomes and maternal non-obstetric serious adverse events (SAEs), taking into consideration confounding and temporal biases.
METHODS
Electronic databases (Ovid MEDLINE ALL, Embase Classic+Embase and the Cochrane Central Register of Controlled Trials) were searched to June 2021 for observational studies assessing associations between influenza vaccination during pregnancy and maternal non-obstetric SAEs and adverse birth outcomes, including preterm birth, spontaneous abortion, stillbirth, small-for-gestational-age birth and congenital anomalies. Studies of live attenuated vaccines, single-arm cohort studies and abstract-only publications were excluded. Records were screened using a liberal accelerated approach initially, followed by a dual independent approach for full-text screening, data extraction and risk of bias assessment. Pairwise meta-analyses were conducted, where two or more studies met methodological criteria for inclusion. The Grading of Recommendations, Assessment, Development and Evaluation approach was used to assess evidence certainty.
RESULTS
Of 9443 records screened, 63 studies were included. Twenty-nine studies (24 cohort and 5 case-control) evaluated seasonal influenza vaccination (trivalent and/or quadrivalent) versus no vaccination and were the focus of our prioritised syntheses; 34 studies of pandemic vaccines (2009 A/H1N1 and others), combinations of pandemic and seasonal vaccines, and seasonal versus seasonal vaccines were also reviewed. Control for confounding and temporal biases was inconsistent across studies, limiting pooling of data. Meta-analyses for preterm birth, spontaneous abortion and small-for-gestational-age birth demonstrated no significant associations with seasonal influenza vaccination. Immortal time bias was observed in a sensitivity analysis of meta-analysing risk-based preterm birth data. In descriptive summaries for stillbirth, congenital anomalies and maternal non-obstetric SAEs, no significant association with increased risk was found in any studies. All evidence was of very low certainty.
CONCLUSIONS
Evidence of very low certainty suggests that seasonal influenza vaccination during pregnancy is not associated with adverse birth outcomes or maternal non-obstetric SAEs. Appropriate control of confounding and temporal biases in future studies would improve the evidence base.
Topics: Infant, Newborn; Female; Pregnancy; Humans; Abortion, Spontaneous; Stillbirth; Influenza A Virus, H1N1 Subtype; Influenza, Human; Premature Birth
PubMed: 37673449
DOI: 10.1136/bmjopen-2022-066182 -
The Cochrane Database of Systematic... Apr 2009Anthrax is a bacterial zoonosis that occasionally causes human disease and is potentially fatal. Anthrax vaccines include a live-attenuated vaccine, an alum-precipitated... (Review)
Review
BACKGROUND
Anthrax is a bacterial zoonosis that occasionally causes human disease and is potentially fatal. Anthrax vaccines include a live-attenuated vaccine, an alum-precipitated cell-free filtrate vaccine, and a recombinant protein vaccine.
OBJECTIVES
To evaluate the effectiveness, immunogenicity, and safety of vaccines for preventing anthrax.
SEARCH STRATEGY
We searched the following databases (November 2008): Cochrane Infectious Diseases Group Specialized Register; CENTRAL (The Cochrane Library 2008, Issue 4); MEDLINE; EMBASE; LILACS; and mRCT. We also searched reference lists.
SELECTION CRITERIA
We included randomized controlled trials (RCTs) of individuals and cluster-RCTs comparing anthrax vaccine with placebo, other (non-anthrax) vaccines, or no intervention; or comparing administration routes or treatment regimens of anthrax vaccine.
DATA COLLECTION AND ANALYSIS
Two authors independently considered trial eligibility, assessed risk of bias, and extracted data. We presented cases of anthrax and seroconversion rates using risk ratios (RR) and 95% confidence intervals (CI). We summarized immunoglobulin G (IgG) concentrations using geometric means. We carried out a sensitivity analysis to investigate the effect of clustering on the results from one cluster-RCT. No meta-analysis was undertaken.
MAIN RESULTS
One cluster-RCT (with 157,259 participants) and four RCTs of individuals (1917 participants) met the inclusion criteria. The cluster-RCT from the former USSR showed that, compared with no vaccine, a live-attenuated vaccine (called STI) protected against clinical anthrax whether given by a needleless device (RR 0.16; 102,737 participants, 154 clusters) or the scarification method (RR 0.25; 104,496 participants, 151 clusters). Confidence intervals were statistically significant in unadjusted calculations, but when a small amount of association within clusters was assumed, the differences were not statistically significant. The four RCTs (of individuals) of inactivated vaccines (anthrax vaccine absorbed and recombinant protective antigen) showed a dose response relationship for the anti-protective antigen IgG antibody titre. Intramuscular administration was associated with fewer injection site reactions than subcutaneous injection, and injection site reaction rates were lower when the dosage interval was longer.
AUTHORS' CONCLUSIONS
One cluster-RCT provides limited evidence that a live-attenuated vaccine is effective in preventing cutaneous anthrax. Vaccines based on anthrax antigens are immunogenic in most vaccinees with few adverse events or reactions. Ongoing randomized controlled trials are investigating the immunogenicity and safety of anthrax vaccines.
Topics: Anthrax; Anthrax Vaccines; Humans; Randomized Controlled Trials as Topic; Vaccines, Attenuated
PubMed: 19370633
DOI: 10.1002/14651858.CD006403.pub2 -
The Pediatric Infectious Disease Journal Dec 2021Rotavirus causes 215,000 deaths from severe childhood diarrhea annually. Concerns exist that a monovalent vaccine (RV1) and a pentavalent vaccine (RV5) may be less... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Rotavirus causes 215,000 deaths from severe childhood diarrhea annually. Concerns exist that a monovalent vaccine (RV1) and a pentavalent vaccine (RV5) may be less effective against rotavirus strains not contained in the vaccines. We estimated the vaccine effectiveness (VE) of RV1 and RV5 against severe rotavirus gastroenteritis caused by vaccine (homotypic) and nonvaccine (partially and fully heterotypic) strains.
METHODS
After conducting a systematic review, we meta-analyzed 31 case-control studies (N = 27,293) conducted between 2006 and 2020 using a random-effects regression model.
RESULTS
In high-income countries, RV1 VE was 10% lower against partially heterotypic (P = 0.04) and fully heterotypic (P = 0.10) compared with homotypic strains (homotypic VE: 90% [95% confidence intervals (CI): 82-94]; partially heterotypic VE: 79% [95% CI: 71-85]; fully heterotypic VE: 80% [95% CI: 65-88]). In middle-income countries, RV1 VE was 14-16% lower against partially heterotypic (P = 0.06) and fully heterotypic (P = 0.04) compared with homotypic strains (homotypic VE: 81% [95% CI: 69-88]; partially heterotypic VE: 67% [95% CI: 54-76]; fully heterotypic VE: 65% [95% CI: 51-75]). Strain-specific RV5 VE differences were less pronounced, and primarily derived from high-income countries. Limited data were available from low-income countries.
CONCLUSIONS
Vaccine effectiveness of RV1 and RV5 was somewhat lower against nonvaccine than vaccine strains. Ongoing surveillance is important to continue long-term monitoring for strain replacement, particularly in low-income settings where data are limited.
Topics: Case-Control Studies; Child; Diarrhea; Hospitalization; Humans; Infant; Rotavirus; Rotavirus Infections; Rotavirus Vaccines; Vaccine Efficacy; Vaccines, Attenuated
PubMed: 34870393
DOI: 10.1097/INF.0000000000003286 -
Vaccines Sep 2022The public health burden of seasonal influenza is significant, and influenza vaccination is the most effective preventive strategy. Nonetheless, the recommendation of... (Review)
Review
INTRODUCTION
The public health burden of seasonal influenza is significant, and influenza vaccination is the most effective preventive strategy. Nonetheless, the recommendation of influenza immunization in the pediatric population is still underrepresented. Our work aimed to assess the cost-effectiveness of pediatric influenza vaccination with the intranasal live-attenuated influenza vaccine (LAIV).
METHODS
We performed a systematic review of publications from PubMed/MEDLINE, Embase, and Scopus, covering the period from 1 January 2000 to 30 April 2022. We searched for economic evaluations that studied the impacts of LAIV among children or the pediatric population. Studies that considered incremental cost-effectiveness ratios (ICERs), in terms of cost per gain in life years, quality adjusted life years, or disability-adjusted life years, were covered. The Consensus Health Economic Criteria (CHEC) Extended Checklist was adopted to check the quality of the included studies.
RESULTS
Thirteen studies were included for the final review that were of good or excellent quality. The implementation of influenza vaccination with intranasal LAIV in the pediatric population was cost-effective when compared to the immunization strategies for the elderly and the high-risk groups alone or with no vaccination. The efficacy of LAIV for children, vaccination coverage, and the vaccine price were significant factors to the cost-effectiveness of influenza vaccination for children. Another significant contribution to the cost-effectiveness was the herd immunity arising from pediatric immunization against influenza.
CONCLUSIONS
The implementation of influenza vaccination in the pediatric population with LAIV is cost-effective. Policymakers and health authorities may consider the evidence on the development of the pediatric influenza vaccination in their immunization schedules.
PubMed: 36146544
DOI: 10.3390/vaccines10091466 -
Open Forum Infectious Diseases 2017This systematic review and meta-analysis describes and consolidates findings from all studies that assessed the effectiveness of live-attenuated influenza vaccine (LAIV)...
BACKGROUND
This systematic review and meta-analysis describes and consolidates findings from all studies that assessed the effectiveness of live-attenuated influenza vaccine (LAIV) against laboratory-confirmed influenza since the 2009 pandemic in children and young adults.
METHODS
A MEDLINE search was conducted for articles published from January 1, 2010 to November 30, 2016. All original publications reporting an effectiveness estimate of LAIV against cases of influenza confirmed by reverse-transcription polymerase chain reaction or culture were retained for analysis. Effectiveness estimates were categorized by LAIV formulation (monovalent, trivalent, and quadrivalent) and strain (any influenza strain, A(H1N1)pdm09, A(H3N2), and B strains). Consolidated estimates were obtained with a random-effects model.
RESULTS
A total of 24 publications presenting 29 observational studies were retained for meta-analysis. Live-attenuated influenza vaccine was not shown to be effective against A(H1N1)pdm09 strains as a monovalent formulation in 2009-2010 or as a trivalent formulation from 2010-2011 to 2013-2014, but consolidated sample sizes were small. It was effective as a quadrivalent formulation but less effective than inactivated influenza vaccine (IIV). Live-attenuated influenza vaccine was consistently effective against B strains and matched A(H3N2) strains but was not shown to provide significant protection against mismatched A(H3N2) strains in 2014-2015.
CONCLUSIONS
These findings confirm that effectiveness of LAIV against A(H1N1)pdm09 strains has been lower than IIV. A systematic investigation has been initiated to determine the root cause of the difference in effectiveness between pre- and postpandemic A(H1N1) vaccine strains and to identify a more consistently effective A(H1N1)pdm09 vaccine strain.
PubMed: 28852675
DOI: 10.1093/ofid/ofx111 -
BMC Medicine Jun 2013Influenza vaccines are most effective when the antigens in the vaccine match those of circulating strains. However, antigens contained in the vaccines do not always... (Comparative Study)
Comparative Study Meta-Analysis Review
BACKGROUND
Influenza vaccines are most effective when the antigens in the vaccine match those of circulating strains. However, antigens contained in the vaccines do not always match circulating strains. In the present work we aimed to examine the vaccine efficacy (VE) afforded by influenza vaccines when they are not well matched to circulating strains.
METHODS
We identified randomized clinical trials (RCTs) through MEDLINE, EMBASE, the Cochrane Library, and references of included RCTs. RCTs reporting laboratory-confirmed influenza among healthy participants vaccinated with antigens of matching and non-matching influenza strains were included. Two independent reviewers screened citations/full-text articles, abstracted data, and appraised risk of bias. Conflicts were resolved by discussion. A random effects meta-analysis was conducted. VE was calculated using the following formula: (1 - relative risk × 100%).
RESULTS
We included 34 RCTs, providing data on 47 influenza seasons and 94,821 participants. The live-attenuated influenza vaccine (LAIV) showed significant protection against mismatched (six RCTs, VE 54%, 95% confidence interval (CI) 28% to 71%) and matched (seven RCTs, VE 83%, 95% CI 75% to 88%) influenza strains among children aged 6 to 36 months. Differences were observed between the point estimates for mismatched influenza A (five RCTs, VE 75%, 95% CI 41% to 90%) and mismatched influenza B (five RCTs, VE 42%, 95% CI 22% to 56%) estimates among children aged 6 to 36 months. The trivalent inactivated vaccine (TIV) also afforded significant protection against mismatched (nine RCTs, VE 52%, 95% CI 37% to 63%) and matched (eight RCTs, VE 65%, 95% CI 54% to 73%) influenza strains among adults. Numerical differences were observed between the point estimates for mismatched influenza A (five RCTs, VE 64%, 95% CI 23% to 82%) and mismatched influenza B (eight RCTs, VE 52%, 95% CI 19% to 72%) estimates among adults. Statistical heterogeneity was low (I2 <50%) across all meta-analyses, except for the LAIV meta-analyses among children (I2 = 79%).
CONCLUSIONS
The TIV and LAIV vaccines can provide cross protection against non-matching circulating strains. The point estimates for VE were different for matching versus non-matching strains, with overlapping CIs.
Topics: Cross Protection; Humans; Influenza Vaccines; Influenza, Human; Randomized Controlled Trials as Topic; Species Specificity; Treatment Outcome; Vaccines, Attenuated
PubMed: 23800265
DOI: 10.1186/1741-7015-11-153 -
The Cochrane Database of Systematic... 2000Plague is endemic in China, Mongolia, Burma, Vietnam, Indonesia, India, large parts of Southern Africa, the United States and South America. There are three types of... (Review)
Review
BACKGROUND
Plague is endemic in China, Mongolia, Burma, Vietnam, Indonesia, India, large parts of Southern Africa, the United States and South America. There are three types of vaccines (live attenuated, killed and F1 fraction) with varying means of administration.
OBJECTIVES
The objective of this review was to assess the effects of vaccines to prevent plague.
SEARCH STRATEGY
We searched Medline, Embase, the Cochrane Controlled Trials Register and reference lists of articles. We handsearched the journal 'Vaccine' and contacted experts in the field.
SELECTION CRITERIA
Randomised trials comparing live and killed plague vaccines against no intervention, placebo, other plague vaccines or vaccines against other disease (control vaccines).
DATA COLLECTION AND ANALYSIS
Three reviewers assessed the eligibility of trials.
MAIN RESULTS
No trials were included.
REVIEWER'S CONCLUSIONS
There is not enough evidence to evaluate the effectiveness of any plague vaccine, or the relative effectiveness between vaccines and their tolerability. Circumstantial data from observational studies suggest that killed types may be more effective and have fewer adverse effects than attenuated types of vaccine. No evidence appears to exist on the long-term effects of any plague vaccine.
Topics: Humans; Plague; Plague Vaccine; Vaccines, Attenuated; Vaccines, Inactivated
PubMed: 10796565
DOI: 10.1002/14651858.CD000976 -
Human Vaccines & Immunotherapeutics Jul 2016Four randomized, double-blind, placebo-controlled studies in 6090 children that investigated the efficacy of live attenuated influenza vaccine (LAIV) upon revaccination... (Review)
Review
Four randomized, double-blind, placebo-controlled studies in 6090 children that investigated the efficacy of live attenuated influenza vaccine (LAIV) upon revaccination of children against laboratory-confirmed cases of influenza in consecutive seasons were reviewed. The efficacy in season 2 of LAIV administered over 2 consecutive seasons was 86.7% (95 % CI: 76.8%, 92.4%) against strains antigenically similar to those contained in the vaccine. The additional efficacy of LAIV administered in season 2 compared to LAIV recipients in season 1 only was 58.4% (28.3%, 75.9%). LAIV administered over 2 consecutive seasons also was more efficacious than was LAIV administered in season 2 only (relative efficacy: 53.9% [17.4%, 74.3%]). Residual efficacy of LAIV administered in season 1 only compared to placebo administered in two consecutive seasons was 56.4% (37.0%, 69.8%). This review did not find any evidence of decreasing efficacy of LAIV when administered during 2 consecutive seasons.
Topics: Child; Child, Preschool; Humans; Immunization, Secondary; Infant; Influenza Vaccines; Placebos; Randomized Controlled Trials as Topic; Treatment Outcome; Vaccines, Attenuated
PubMed: 26751513
DOI: 10.1080/21645515.2015.1115164 -
Human Vaccines & Immunotherapeutics Nov 2016Antigenic drift of seasonal influenza viruses and the occasional introduction of influenza viruses of novel subtypes into the human population complicate the timely... (Review)
Review
Antigenic drift of seasonal influenza viruses and the occasional introduction of influenza viruses of novel subtypes into the human population complicate the timely production of effective vaccines that antigenically match the virus strains that cause epidemic or pandemic outbreaks. The development of game-changing vaccines that induce broadly protective immunity against a wide variety of influenza viruses is an unmet need, in which recombinant viral vectors may provide. Use of viral vectors allows the delivery of any influenza virus antigen, or derivative thereof, to the immune system, resulting in the optimal induction of virus-specific B- and T-cell responses against this antigen of choice. This systematic review discusses results obtained with vectored influenza virus vaccines and advantages and disadvantages of the currently available viral vectors.
Topics: Animals; Drug Carriers; Genetic Vectors; Humans; Influenza Vaccines; Vaccines, Attenuated; Vaccines, Synthetic; Viruses
PubMed: 27455345
DOI: 10.1080/21645515.2016.1210729