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1.
Vaccines (Basel) ; 10(1)2021 Dec 25.
Article in English | MEDLINE | ID: covidwho-1580357

ABSTRACT

The high transmissibility, mortality, and morbidity rate of the SARS-CoV-2 Delta (B.1.617.2) variant have raised concerns regarding vaccine effectiveness (VE). To address this issue, all publications relevant to the effectiveness of vaccines against the Delta variant were searched in the Web of Science, Scopus, EMBASE, and Medline (via PubMed) databases up to 15 October 2021. A total of 15 studies (36 datasets) were included in the meta-analysis. After the first dose, the VE against the Delta variant for each vaccine was 0.567 (95% CI 0.520-0.613) for Pfizer-BioNTech, 0.72 (95% CI 0.589-0.822) for Moderna, 0.44 (95% CI 0.301-0.588) for AstraZeneca, and 0.138 (95% CI 0.076-0.237) for CoronaVac. Meta-analysis of 2,375,957 vaccinated cases showed that the Pfizer-BioNTech vaccine had the highest VE against the infection after the second dose, at 0.837 (95% CI 0.672-0.928), and third dose, at 0.972 (95% CI 0.96-0.978), as well as the highest VE for the prevention of severe infection or death, at 0.985 (95% CI 0.95-0.99), amongst all COVID-19 vaccines. The short-term effectiveness of vaccines, especially mRNA-based vaccines, for the prevention of the Delta variant infection, hospitalization, severe infection, and death is supported by this study. Limitations include a lack of long-term efficacy data, and under-reporting of COVID-19 infection cases in observational studies, which has the potential to falsely skew VE rates. Overall, this study supports the decisions by public health decision makers to promote the population vaccination rate to control the Delta variant infection and the emergence of further variants.

2.
Vaccines (Basel) ; 9(5)2021 May 06.
Article in English | MEDLINE | ID: covidwho-1224272

ABSTRACT

The current study systematically reviewed, summarized and meta-analyzed the clinical features of the vaccines in clinical trials to provide a better estimate of their efficacy, side effects and immunogenicity. All relevant publications were systematically searched and collected from major databases up to 12 March 2021. A total of 25 RCTs (123 datasets), 58,889 cases that received the COVID-19 vaccine and 46,638 controls who received placebo were included in the meta-analysis. In total, mRNA-based and adenovirus-vectored COVID-19 vaccines had 94.6% (95% CI 0.936-0.954) and 80.2% (95% CI 0.56-0.93) efficacy in phase II/III RCTs, respectively. Efficacy of the adenovirus-vectored vaccine after the first (97.6%; 95% CI 0.939-0.997) and second (98.2%; 95% CI 0.980-0.984) doses was the highest against receptor-binding domain (RBD) antigen after 3 weeks of injections. The mRNA-based vaccines had the highest level of side effects reported except for diarrhea and arthralgia. Aluminum-adjuvanted vaccines had the lowest systemic and local side effects between vaccines' adjuvant or without adjuvant, except for injection site redness. The adenovirus-vectored and mRNA-based vaccines for COVID-19 showed the highest efficacy after first and second doses, respectively. The mRNA-based vaccines had higher side effects. Remarkably few experienced extreme adverse effects and all stimulated robust immune responses.

4.
Rev Med Virol ; 30(4): e2112, 2020 07.
Article in English | MEDLINE | ID: covidwho-538242

ABSTRACT

INTRODUCTION: Within this large-scale study, we compared clinical symptoms, laboratory findings, radiographic signs, and outcomes of COVID-19, SARS, and MERS to find unique features. METHOD: We searched all relevant literature published up to February 28, 2020. Depending on the heterogeneity test, we used either random or fixed-effect models to analyze the appropriateness of the pooled results. Study has been registered in the PROSPERO database (ID 176106). RESULT: Overall 114 articles included in this study; 52 251 COVID-19 confirmed patients (20 studies), 10 037 SARS (51 studies), and 8139 MERS patients (43 studies) were included. The most common symptom was fever; COVID-19 (85.6%, P < .001), SARS (96%, P < .001), and MERS (74%, P < .001), respectively. Analysis showed that 84% of Covid-19 patients, 86% of SARS patients, and 74.7% of MERS patients had an abnormal chest X-ray. The mortality rate in COVID-19 (5.6%, P < .001) was lower than SARS (13%, P < .001) and MERS (35%, P < .001) between all confirmed patients. CONCLUSIONS: At the time of submission, the mortality rate in COVID-19 confirmed cases is lower than in SARS- and MERS-infected patients. Clinical outcomes and findings would be biased by reporting only confirmed cases, and this should be considered when interpreting the data.


Subject(s)
Betacoronavirus , Coronavirus Infections , Middle East Respiratory Syndrome Coronavirus , Pandemics , Pneumonia, Viral , Severe Acute Respiratory Syndrome , Blood Cell Count , COVID-19 , China , Coronavirus Infections/diagnosis , Coronavirus Infections/mortality , Coronavirus Infections/physiopathology , Cough , Dyspnea , Female , Fever , Hospitalization , Humans , Lung/diagnostic imaging , Male , Pneumonia, Viral/diagnosis , Pneumonia, Viral/mortality , Pneumonia, Viral/physiopathology , Risk Factors , SARS-CoV-2 , Severe Acute Respiratory Syndrome/diagnosis , Severe Acute Respiratory Syndrome/mortality , Severe Acute Respiratory Syndrome/physiopathology , Travel
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