ABSTRACT
OBJECTIVES: Influenza vaccination is an effective method for preventing influenza virus infection. Herein, we performed a meta-analysis to quantify global influenza vaccination rates (IVRs) and the factors influencing its uptake in the general population, individuals with chronic diseases, pregnant women, and healthcare workers. METHODS: Related articles were obtained from online databases and screened according to the inclusion criteria. The pooled IVRs were calculated using the random effects model. Subgroup analyses and multivariate meta-regression were performed to determine the factors associated with influenza vaccine uptake. RESULTS: e included 522 studies from 68 countries/regions. Most studies were conducted in the European region (247 studies), followed by the Western Pacific (135 studies) and American regions (100 studies). The IVRs with 95% confidence intervals (CIs) in the general population were lower (24.96%, 23.45%-26.50%) than in individuals with chronic diseases (41.65%, 40.08%-43.23%), healthcare workers (36.57%, 33.74%-39.44%), and pregnant women (25.92%, 23.18%-28.75%). The IVRs in high-income countries/regions were significantly higher than that in middle-income countries/regions. A free national or regional vaccination policy, perception of influenza vaccine efficacy and disease severity, a recommendation from healthcare workers, and having a history of influenza vaccination were positive factors for vaccine uptake (P <0.01). CONCLUSION: Overall, global IVRs were low, especially in the general population. The studies on the IVRs, especially for priority populations, should be strengthened in Eastern Mediterranean, South-East Asian, and African regions. Free vaccination policies and the dissemination of continuous awareness campaigns are effective measures to enhance vaccination uptake.
ABSTRACT
OBJECTIVES: The role of asymptomatic infections in the transmission of COVID-19 have drawn considerable attention. Here, we performed a meta-analysis to summarize the epidemiological and radiographical characteristics of asymptomatic infections associated with COVID-19. METHODS: Data on the epidemiological and radiographical characteristics of asymptomatic infections were extracted from the existing literature. Pooled proportions with 95% confidence intervals were then calculated using a random effects model. RESULTS: A total of 104 studies involving 20,152 cases were included. The proportion of asymptomatic individuals among those with COVID-19 was 13.34% (10.86%-16.29%), among which presymptomatic and covert infections accounted for 7.64% (4.02%-14.04%) and 8.44% (5.12%-13.62%), respectively. The proportions of asymptomatic infections among infected children and healthcare workers were 32.24% (23.08%-42.13%) and 36.96% (18.51%-60.21%), respectively. The proportion of asymptomatic infections was significantly higher after 2020/02/29 than before (33.53% vs 10.19%) and in non-Asian regions than in Asia (28.76% vs 11.54%). The median viral shedding duration of asymptomatic infections was 14.14 days (11.25-17.04). A total of 47.62% (31.13%-72.87%) of asymptomatic infections showed lung abnormalities, especially ground-glass opacity (41.11% 19.7%-85.79%). CONCLUSIONS: Asymptomatic infections were more commonly found in infected children and healthcare workers and increased after 2020/02/29 and in non-Asian regions. Chest radiographical imaging could be conducive to the early identification of asymptomatic infections.
Subject(s)
Asymptomatic Infections/epidemiology , COVID-19/diagnostic imaging , COVID-19/epidemiology , Virus Shedding , Humans , Radiography, Thoracic , SARS-CoV-2ABSTRACT
BACKGROUND: Since the outbreak of coronavirus disease 2019 (COVID-19), many researchers in China have performed related clinical research. However, systematic reviews of the registered clinical trials are still lacking. Therefore, we conducted a systematic review of clinical trials for COVID-19 to summarize their characteristics. METHODS: This study is based on the PRISMA recommendations in the Cochrane handbook. The Chinese Clinical Registration Center and the ClinicalTrials.gov databases were searched to identify registered clinical trials related to COVID-19. The retrieval inception date was February 9, 2020. Two researchers independently selected the literature based on the inclusion and exclusion criteria, extracted data, and evaluated the risk of bias. RESULTS: A total of 75 registered clinical trials (63 interventional studies and 12 observational studies) for COVID-19 were identified. The majority of clinical trials were sponsored by Chinese hospitals. Only 11 trials have begun to recruit patients, and none of the registered clinical trials have been completed; 34 trials were early clinical exploratory trials or in the pre-experiment stage, 13 trials were phase III, and four trials were phase IV. The intervention methods included traditional Chinese medicine in 26 trials, Western medicine in 30 trials, and integrated traditional Chinese medicine and Western medicine in 19 trials. The subjects were primarily non-critical adult patients (≥ 18 years old). The median sample size of the trials was 100 (IQR: 60-200), and the median length of the trial periods was 179 d (IQR: 94-366 d). The main outcomes were clinical observation and examinations. Overall, the methodological quality of both the interventional trials and observational studies was low. CONCLUSIONS: Intensive clinical trials on the treatment of COVID-19 using traditional Chinese medicine and Western medicine are ongoing or will be performed in China. However, based on the uncertain methodological quality, small sample size, and long trial duration, we will not be able to obtain reliable, high-quality clinical evidence regarding the treatment of COVID-19 in the near future. Improving the quality of study design, prioritizing promising drugs, and using different designs and statistical methods are worth advocating and recommending for clinical trials of COVID-19 in the future.