Project description:BackgroundDose fractionation of a coronavirus disease 2019 (COVID-19) vaccine could effectively accelerate global vaccine coverage, while supporting evidence of efficacy, immunogenicity, and safety are unavailable, especially with emerging variants.MethodsWe systematically reviewed clinical trials that reported dose-finding results and estimated the dose-response relationship of neutralizing antibodies (nAbs) of COVID-19 vaccines using a generalized additive model. We predicted the vaccine efficacy against both ancestral and variants, using previously reported correlates of protection and cross-reactivity. We also reviewed and compared seroconversion to nAbs, T cell responses, and safety profiles between fractional and standard dose groups.ResultsWe found that dose fractionation of mRNA and protein subunit vaccines could induce SARS-CoV-2-specific nAbs and T cells that confer a reasonable level of protection (i.e., vaccine efficacy > 50%) against ancestral strains and variants up to Omicron. Safety profiles of fractional doses were non-inferior to the standard dose.ConclusionsDose fractionation of mRNA and protein subunit vaccines may be safe and effective, which would also vary depending on the characteristics of emerging variants and updated vaccine formulations.
Project description:Rationale and objectiveCOVID-19 vaccination is the most effective way to prevent COVID-19. For chronic kidney disease patients on long-term dialysis, there is a lack of evidence on the pros and cons of COVID-19 vaccination. This study was conducted to investigate the immunogenicity and safety of COVID-19 vaccines in patients on dialysis.MethodsPubMed, MEDLINE, EMBASE, and the Cochrane Library were systemically searched for cohort, randomized controlled trials (RCTs), and cross-sectional studies. Data on immunogenicity rate, antibody titer, survival rate, new infection rate, adverse events, type of vaccine, and patient characteristics such as age, sex, dialysis vintage, immunosuppression rate, and prevalence of diabetes were extracted and analyzed using REVMAN 5.4 and Stata software. A random effects meta-analysis was used to perform the study.ResultsWe screened 191 records and included 38 studies regarding 5,628 participants. The overall immunogenicity of dialysis patients was 87% (95% CI, 84-89%). The vaccine response rate was 85.1 in hemodialysis patients (HDPs) (1,201 of 1,412) and 97.4% in healthy controls (862 of 885). The serological positivity rate was 82.9% (777 of 937) in infection-naive individuals and 98.4% (570 of 579) in patients with previous infection. The Standard Mean Difference (SMD) of antibody titers in dialysis patients with or without previous COVID-19 infection was 1.14 (95% CI, 0.68-1.61). Subgroup analysis showed that the immunosuppression rate was an influential factor affecting the immunogenicity rate (P < 0.0001). Nine studies reported safety indices, among which four local adverse events and seven system adverse events were documented.ConclusionsVaccination helped dialysis patients achieve effective humoral immunity, with an overall immune efficiency of 87.5%. Dialysis patients may experience various adverse events after vaccination; however, the incidence of malignant events is very low, and no reports of death or acute renal failure after vaccination are available, indicating that vaccine regimens may be necessary.Systematic review registrationhttps://www.crd.york.ac.uk/PROSPERO/display_record.asp?ID=CRD42022342565, identifier: CRD42022342565.
Project description:BackgroundTo date, coronavirus disease 2019 (COVID-19) becomes increasingly fierce due to the emergence of variants. Rapid herd immunity through vaccination is needed to block the mutation and prevent the emergence of variants that can completely escape the immune surveillance. We aimed to systematically evaluate the effectiveness and safety of COVID-19 vaccines in the real world and to establish a reliable evidence-based basis for the actual protective effect of the COVID-19 vaccines, especially in the ensuing waves of infections dominated by variants.MethodsWe searched PubMed, Embase and Web of Science from inception to July 22, 2021. Observational studies that examined the effectiveness and safety of SARS-CoV-2 vaccines among people vaccinated were included. Random-effects or fixed-effects models were used to estimate the pooled vaccine effectiveness (VE) and incidence rate of adverse events after vaccination, and their 95% confidence intervals (CI).ResultsA total of 58 studies (32 studies for vaccine effectiveness and 26 studies for vaccine safety) were included. A single dose of vaccines was 41% (95% CI: 28-54%) effective at preventing SARS-CoV-2 infections, 52% (31-73%) for symptomatic COVID-19, 66% (50-81%) for hospitalization, 45% (42-49%) for Intensive Care Unit (ICU) admissions, and 53% (15-91%) for COVID-19-related death; and two doses were 85% (81-89%) effective at preventing SARS-CoV-2 infections, 97% (97-98%) for symptomatic COVID-19, 93% (89-96%) for hospitalization, 96% (93-98%) for ICU admissions, and 95% (92-98%) effective for COVID-19-related death, respectively. The pooled VE was 85% (80-91%) for the prevention of Alpha variant of SARS-CoV-2 infections, 75% (71-79%) for the Beta variant, 54% (35-74%) for the Gamma variant, and 74% (62-85%) for the Delta variant. The overall pooled incidence rate was 1.5% (1.4-1.6%) for adverse events, 0.4 (0.2-0.5) per 10 000 for severe adverse events, and 0.1 (0.1-0.2) per 10 000 for death after vaccination.ConclusionsSARS-CoV-2 vaccines have reassuring safety and could effectively reduce the death, severe cases, symptomatic cases, and infections resulting from SARS-CoV-2 across the world. In the context of global pandemic and the continuous emergence of SARS-CoV-2 variants, accelerating vaccination and improving vaccination coverage is still the most important and urgent matter, and it is also the final means to end the pandemic.
Project description:IntroductionThere are concerns regarding the effectiveness and safety of SARS-CoV-2 vaccine in inflammatory Bowel Disease (IBD) patients. This systematic review and meta-analysis comprehensively summarises the available literature regarding the safety and effectiveness of SARS-CoV-2 vaccine in IBD.MethodsThree independent reviewers performed a comprehensive review of all original articles describing the response of SARS-CoV-2 vaccines in patients with IBD. Primary outcomes were (1) pooled seroconversion rate SARS-CoV-2 vaccination in IBD patients (2) comparison of breakthrough COVID-19 infection rate SARS-CoV-2 vaccination in IBD patients with control cohort and (3) pooled adverse event rate of SARS-CoV-2 vaccine. All outcomes were evaluated for one and two doses of SARS-CoV-2 vaccine. Meta-regression was performed. Probability of publication bias was assessed using funnel plots and with Egger's test.ResultsTwenty-one studies yielded a pooled seroconversion rate of 73.7% and 96.8% in IBD patients after one and two doses of SARS-CoV-2 vaccine respectively. Sub-group analysis revealed non-statistically significant differences between different immunosuppressive regimens for seroconversion. Meta-regression revealed that the vaccine type and study location independently influenced seroconversion rates. There was no statistically significant difference in breakthrough infection in IBD patients as compared to control after vaccination.ConclusionIn summary, the systematic review and meta-analysis suggest that SARS-CoV-2 vaccine is safe and effective in IBD patients.
Project description:BackgroundThis review summarizes the factors influencing the efficacy and safety of the COVID-19 vaccine in LTR through meta-analysis, hoping to provide strategies for vaccine use.MethodsElectronic databases were screened for studies on mRNA vaccines in LTR. The primary outcome was the pooled seroconversion rate, and the secondary outcome was the incidence of adverse events+breakthrough infections. Subgroup analyses were made based on BMI, associated comorbidities, presence of baseline leukopenia, time since transplant, and drugs used.ResultIn total, 31 articles got included. The pooled seroconversion rate after at least two doses of SARS-CoV-2 vaccination was 72% (95% CI [0.52-0.91). With significant heterogeneity among studies I2 = 99.9%, the seroconversion rate was about 72% (95%CI [0.66-0.75]), from the studies reporting two doses of vaccine slightly higher around 75%(95%CI [0.29-1.22]) from studies reporting three doses. The pooled seroconversion rate within the lower to normal BMI group was 74% (95% CI [0.22-1.27], Pi=0.005) against 67% (95% CI [0.52-0.81], Pi=0.000) in the high BMI group. The pooled seroconversion rate in the ''positive leukopenia'' group was the lowest, 59%. Leukopenia could influence the vaccine seroconversion rate in LTR. From the time since transplant analysis after setting seven years as cut off point, the pooled seroconversion rate after at least two doses of COVID-19 vaccination was 53% (95% CI [0.18-0.83], P=0.003, I2 = 99.6%) in <7years group and 83% (95% CI [0.76-0.90], P=0.000 I2 = 95.7%) in > 7years group. The only time since transplantation had reached statistical significance to be considered a risk factor predictor of poor serological response (OR=1.27 95%CI [1.03-1.55], P=0.024). The breakthrough infection rate after vaccination was very low2% (95% CI 0.01-0.03, I2 = 63.0%), and the overall incidence of adverse events, which included mainly pain at the injection site and fatigue, was 18% (95%CI [0.11-0.25], I2 = 98.6%, Pi=0.000).ConclusionThe seroconversion rate in LTR vaccinated with at least two doses of mRNA COVID-19 vaccine could be significantly affected by the vaccine type, immunosuppressant used, BMI, leukopenia, associated comorbidities, and time since transplantation. Nevertheless, booster doses are still recommended for LTR.
Project description:ObjectiveReports of neurological involvement during Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) infection course are increasingly described. The aim of this review is to provide a clinical approach of SARS-CoV-2 neurological complications based on the direct or indirect (systemic/immune-mediated) role of the SARS-CoV-2 in their genesis.MethodsA review of the current literature has been carried out up to May 20th 2020 according to the PRISMA guidelines. All case series and reports of adult neurological manifestations associated to SARS-CoV-2 published in English were considered. Review and fundamental research studies on Coronaviruses neuroinvasive potential were analyzed to support pathogenic hypothesis and possible underlying mechanisms. Clinical patterns were subdivided into three groups according to putative underlying mechanisms: direct invasion of central or peripheral nervous system, systemic disorders leading to acute CNS injuries and post-infectious neurological syndromes (PINS).ResultsSixteen case series and 26 case reports for a total of 903 patients were identified presenting with neurological involvement during SARS-CoV-2 infection. Hypo/anosmia and dys/ageusia were found in 826 patients and mainly attributed to direct viral invasion. Cerebrovascular complications occurred in 51 patients and related to viral infection associated systemic inflammation. PINS were described in only 26 patients. A wide heterogeneity of these reports emerged concerning the extension of the clinical examination and ancillary exams performed.ConclusionsNeurological complications of SARS-CoV-2 are mainly related to olfactory and gustatory sensory perception disorders through possible direct nervous system invasion while cerebrovascular disease and PINS are rare and due to distinct and indirect pathophysiological mechanisms.
Project description:ObjectiveTo systematically evaluate the effectiveness and safety of the SARS-CoV-2 vaccines currently undergoing clinical trials.MethodsPubMed, EMBASE, and Cochrane Library databases were searched to collect open human COVID-19 vaccines randomized controlled trials, without limiting the search time and language. The research papers collected in the above-mentioned databases were initially screened according to the title and abstract content and merged, and the repeated ones were removed. After reading the full text of the remaining research, the studies that did not meet the inclusion criteria were excluded, and finally, nine studies were obtained. After extracting the statistical data of adverse events in the study, load them into Review Manager for heterogeneity analysis.ResultsThe incidence of adverse reactions of inactivated virus vaccines, RNA vaccines, and adenovirus vector vaccines was higher than that of placebo. Common adverse reactions included pain, swelling, and fever at the injection site.ConclusionFrom the perspective of effectiveness, RNA vaccine > adenovirus vector vaccine > inactivated virus vaccine. From the perspective of safety, the incidence of adverse reactions of the three vaccines is higher than that of a placebo, and the incidence of adverse reactions of the adenovirus vector vaccine is higher.
Project description:BackgroundCorona Virus Disease 2019 (COVID-19) mRNA vaccine effectiveness (VE) has recently declined, and reports about COVID-19 breakthrough infection have increased. We aimed to conduct a meta-analysis on population-based studies of the prevalence and incidence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) breakthrough infection amongst older adults worldwide.MethodsStudies from PubMed, Embase, Cochrane Library, and Web of Science were systematically screened to determine the prevalence and incidence of SARS-CoV-2 breakthrough infection in older adults from inception to November 2, 2022. Our meta-analysis included 30 studies, all published in English. Pooled estimates were calculated using a random-effect model through the inverse variance method. Publication bias was tested through funnel plots and Egger's regression test, and sensitivity analyses were performed to confirm the robustness of the results. This research was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.ResultsThirty publications were included in this meta-analysis (17 on prevalence, 17 on incidence, and 4 on both). The pooled prevalence of COVID-19 breakthrough infection among older adults was 7.7 per 1,000 persons (95% confidence interval [95%CI] 4.0-15.0). At the same time, the pooled incidence was 29.1 per 1000 person-years (95%CI 15.2-55.7).ConclusionsThis meta-analysis provides estimates of prevalence and incidence in older adults. We concluded that the prevalence and incidence of SARS-CoV-19 breakthrough infection in older people was low. The prevalence and incidence of breakthrough infection admitted to hospital, severe-critical, and deathly was significantly lower. Otherwise, there was considerable heterogeneity among estimates in this study, which should be considered when interpreting the results.
Project description:ImportanceEstimates of the rate of waning of vaccine effectiveness (VE) against COVID-19 are key to assess population levels of protection and future needs for booster doses to face the resurgence of epidemic waves.ObjectiveTo quantify the progressive waning of VE associated with the Delta and Omicron variants of SARS-CoV-2 by number of received doses.Data sourcesPubMed and Web of Science were searched from the databases' inception to October 19, 2022, as well as reference lists of eligible articles. Preprints were included.Study selectionSelected studies for this systematic review and meta-analysis were original articles reporting estimates of VE over time against laboratory-confirmed SARS-CoV-2 infection and symptomatic disease.Data extraction and synthesisEstimates of VE at different time points from vaccination were retrieved from original studies. A secondary data analysis was performed to project VE at any time from last dose administration, improving the comparability across different studies and between the 2 considered variants. Pooled estimates were obtained from random-effects meta-analysis.Main outcomes and measuresOutcomes were VE against laboratory-confirmed Omicron or Delta infection and symptomatic disease and half-life and waning rate associated with vaccine-induced protection.ResultsA total of 799 original articles and 149 reviews published in peer-reviewed journals and 35 preprints were identified. Of these, 40 studies were included in the analysis. Pooled estimates of VE of a primary vaccination cycle against laboratory-confirmed Omicron infection and symptomatic disease were both lower than 20% at 6 months from last dose administration. Booster doses restored VE to levels comparable to those acquired soon after the administration of the primary cycle. However, 9 months after booster administration, VE against Omicron was lower than 30% against laboratory-confirmed infection and symptomatic disease. The half-life of VE against symptomatic infection was estimated to be 87 days (95% CI, 67-129 days) for Omicron compared with 316 days (95% CI, 240-470 days) for Delta. Similar waning rates of VE were found for different age segments of the population.Conclusions and relevanceThese findings suggest that the effectiveness of COVID-19 vaccines against laboratory-confirmed Omicron or Delta infection and symptomatic disease rapidly wanes over time after the primary vaccination cycle and booster dose. These results can inform the design of appropriate targets and timing for future vaccination programs.
Project description:BackgroundVarious modalities of vaccines against coronavirus disease 2019 (COVID-19), based on different platforms and immunization procedures, have been successively approved for marketing worldwide. A comprehensive review for clinical trials assessing the safety of COVID-19 vaccines is urgently needed to make an accurate judgment for mass vaccination.Main textA systematic review and meta-analysis was conducted to determine the safety of COVID-19 vaccine candidates in randomized controlled trials (RCTs). Data search was performed in PubMed, Embase, Cochrane library, Scopus, Web of Science, and MedRxiv. Included articles were limited to RCTs on COVID-19 vaccines. A total of 73,633 subjects from 14 articles were included to compare the risks of adverse events following immunization (AEFI) after vaccinating different COVID-19 vaccines. Pooled risk ratios (RR) of total AEFI for inactivated vaccine, viral-vectored vaccine, and mRNA vaccine were 1.34 [95% confidence interval (CI) 1.11-1.61, P < 0.001], 1.65 (95% CI 1.31-2.07, P < 0.001), and 2.01 (95% CI 1.78-2.26, P < 0.001), respectively. No significant differences on local and systemic AEFI were found between the first dose and second dose. In addition, people aged ≤ 55 years were at significantly higher risk of AEFI than people aged ≥ 56 years, with a pooled RR of 1.25 (95% CI 1.15-1.35, P < 0.001).ConclusionsThe safety and tolerance of current COVID-19 vaccine candidates are acceptable for mass vaccination, with inactivated COVID-19 vaccines candidates having the lowest reported AEFI. Long-term surveillance of vaccine safety is required, especially among elderly people with underlying medical conditions.