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Journal of Microbiology, Immunology,... Feb 2021Since the outbreak of coronavirus disease 2019 (COVID-19) in late December 2019, it has brought significant harm and challenges to over 200 countries and regions around...
Since the outbreak of coronavirus disease 2019 (COVID-19) in late December 2019, it has brought significant harm and challenges to over 200 countries and regions around the world. However, there is increasing evidence that many patients with COVID-19 are asymptomatic or have only mild symptoms, but they are able to transmit the virus to others. There are difficulties in screening for asymptomatic infections, which makes it more difficult for national prevention and control of this epidemic. This article reviews the characteristics, treatment, and outcomes of asymptomatic infections with COVID-19, hoping it would be helpful for early prevention and control of this severe public health threat worldwide.
Topics: Asymptomatic Infections; COVID-19; COVID-19 Nucleic Acid Testing; Disease Outbreaks; Humans; SARS-CoV-2; Treatment Outcome
PubMed: 32425996
DOI: 10.1016/j.jmii.2020.05.001 -
Infectious Diseases of Poverty Jun 2020
Topics: Asymptomatic Infections; Betacoronavirus; COVID-19; China; Coronavirus Infections; Humans; Pandemics; Pneumonia, Viral; SARS-CoV-2
PubMed: 32564770
DOI: 10.1186/s40249-020-00679-2 -
Mathematical Biosciences and... Jul 2022In this paper, we propose a new mathematical model to study the epidemic and economic consequences of COVID-19, with a focus on the interaction between the disease...
In this paper, we propose a new mathematical model to study the epidemic and economic consequences of COVID-19, with a focus on the interaction between the disease transmission, the pandemic management, and the economic growth. We consider both the symptomatic and asymptomatic infections and incorporate the effectiveness of disease control into the respective transmission rates. Meanwhile, the progression of the pandemic and the evolution of the susceptible, infectious and recovered population groups directly impact the mitigation and economic development levels. We fit this model to the reported COVID-19 cases and unemployment rates in the US state of Tennessee, as a demonstration of a real-world application of the modeling framework.
Topics: Asymptomatic Infections; COVID-19; Humans; Models, Economic; Pandemics; SARS-CoV-2
PubMed: 35942777
DOI: 10.3934/mbe.2022449 -
Frontiers in Cellular and Infection... 2021Blocking malaria transmission is critical to malaria control programs but remains a major challenge especially in endemic regions with high levels of asymptomatic... (Review)
Review
Blocking malaria transmission is critical to malaria control programs but remains a major challenge especially in endemic regions with high levels of asymptomatic infections. New strategies targeting the transmissible sexual stages of the parasite, called gametocytes, are needed. This review focuses on gametocytogenesis and . Highlighting advances made elucidating genes required for gametocyte production and identifying key questions that remain unanswered such as the factors and regulatory mechanisms that contribute to gametocyte induction, and the mechanism of sequestration. Tools available to begin to address these issues are also described to facilitate advances in our understanding of this important stage of the life cycle.
Topics: Animals; Asymptomatic Infections; Life Cycle Stages; Malaria; Malaria, Falciparum; Plasmodium falciparum
PubMed: 34926328
DOI: 10.3389/fcimb.2021.790067 -
Maternal & Child Nutrition Jan 2023Inadequate diet and frequent symptomatic infections are considered major causes of growth stunting in low-income countries, but interventions targeting these risk...
Inadequate diet and frequent symptomatic infections are considered major causes of growth stunting in low-income countries, but interventions targeting these risk factors have achieved limited success. Asymptomatic infections can restrict growth, but little is known about their role in global stunting prevalence. We investigated factors related to length-for-age Z-score (LAZ) at 24 months by constructing an interconnected network of various infections, biomarkers of inflammation (as assessed by alpha-1-acid glycoprotein [AGP]), and growth (insulin-like growth factor 1 [IGF-1] and collagen X biomarker [CXM]) at 18 months, as well as other children, maternal, and household level factors. Among 604 children, there was a continuous decline in mean LAZ and increased mean length deficit from birth to 24 months. At 18 months of age, the percentage of asymptomatic children who carried each pathogen was: 84.5% enterovirus, 15.5% parechovirus, 7.7% norovirus, 4.6% rhinovirus, 0.6% rotavirus, 69.6% Campylobacter, 53.8% Giardia lamblia, 11.9% malaria parasites, 10.2% Shigella, and 2.7% Cryptosporidium. The mean plasma IGF-1 concentration was 12.5 ng/ml and 68% of the children had systemic inflammation (plasma AGP concentration >1 g/L). Shigella infection was associated with lower LAZ at 24 months through both direct and indirect pathways, whereas enterovirus, norovirus, Campylobacter, Cryptosporidium, and malaria infections were associated with lower LAZ at 24 months indirectly, predominantly through increased systemic inflammation and reduced plasma IGF-1 and CXM concentration at 18 months.
Topics: Child, Preschool; Humans; Infant; Asymptomatic Infections; Biomarkers; Cryptosporidiosis; Cryptosporidium; Growth Disorders; Inflammation; Insulin-Like Growth Factor I; Malaria
PubMed: 36111423
DOI: 10.1111/mcn.13417 -
International Journal of Infectious... Sep 2023The burden of asymptomatic dengue infections is understudied. Therefore, we systematically reviewed the literature to estimate the global prevalence of asymptomatic... (Meta-Analysis)
Meta-Analysis
OBJECTIVES
The burden of asymptomatic dengue infections is understudied. Therefore, we systematically reviewed the literature to estimate the global prevalence of asymptomatic dengue infections.
METHODS
We searched cross-sectional studies reporting the prevalence of asymptomatic dengue infections from PubMed, Scopus, and Embase. Prevalence of asymptomatic dengue infections was pooled and reported as proportions with a 95% confidence interval (CI). This systematic review protocol was a priori registered in The International Prospective Register of Systematic Reviews (Reg: No. CRD42020218446).
RESULTS
We included 41 studies with 131,953 cases in our analysis. The overall pooled prevalence of asymptomatic dengue infections was 59.26% (95% CI: 43.76-74.75, I = 99.93%), with 65.52% (95% CI: 38.73-92.32, I = 99.95%) during outbreaks and 30.78% (95% CI: 21.39-40.16, I = 98.78%) during non-outbreak periods. The pooled prevalence among the acutely infected individuals was 54.52% (95% CI: 17.73-46.76, I = 99.91%), whereas, among primary and secondary asymptomatic dengue infections, it was 65.36% (95% CI: 45.76-84.96, I = 98.82) and 48.99% (95% CI: 27.85-70.13, I = 99.08%) respectively.
CONCLUSION
The majority of dengue cases are asymptomatic and may play a significant role in disease transmission. Public health strategies aimed at dengue outbreak response and mitigation of disease burden should include early detection of asymptomatic cases.
Topics: Humans; Prevalence; Cross-Sectional Studies; Asymptomatic Infections; Coinfection; Dengue
PubMed: 37463631
DOI: 10.1016/j.ijid.2023.07.010 -
Public Health Feb 2022Countries throughout the world are experiencing COVID-19 viral load in their populations, leading to potential transmission and infectivity of asymptomatic COVID-19... (Meta-Analysis)
Meta-Analysis Review
OBJECTIVES
Countries throughout the world are experiencing COVID-19 viral load in their populations, leading to potential transmission and infectivity of asymptomatic COVID-19 cases. The current systematic review and meta-analysis aims to investigate the role of asymptomatic infection and transmission reported in family clusters, adults, children and health care workers, globally.
STUDY DESIGN
Systematic review and meta-analysis.
METHODS
An online literature search of PubMed, Google Scholar, medRixv and BioRixv was performed using standard Boolean operators and included studies published up to 17 August 2021. For the systematic review, case reports, short communications and retrospective studies were included to ensure sufficient asymptomatic COVID-19 transmission data were reported. For the quantitative synthesis (meta-analysis), participant data from a collection of cohort studies focusing on groups of familial clusters, adults, children and health care workers were included. Inconsistency among studies was assessed using I statistics. The data synthesis was computed using the STATA 16.0 software.
RESULTS
This study showed asymptomatic transmission among familial clusters, adults, children and health care workers of 15.72%, 29.48%, 24.09% and 0%, respectively. Overall, asymptomatic transmission was 24.51% (95% confidence interval [CI]: 14.38, 36.02) among all studied population groups, with a heterogeneity of I = 95.30% (P < 0.001). No heterogeneity was seen in the population subgroups of children and health care workers. The risk of bias in all included studies was assessed using the Newcastle Ottawa Scale.
CONCLUSIONS
For minimising the spread of COVID-19 within the community, this study found that following the screening of asymptomatic cases and their close contacts for chest CT scan (for symptomatic patients), even after negative nucleic acid testing, it is essential to perform a rigorous epidemiological history, early isolation, social distancing and an increased quarantine period (a minimum of 14-28 days). This systematic review and meta-analysis supports the notion of asymptomatic COVID-19 infection and person-to-person transmission and suggests that this is dependent on the varying viral incubation period among individuals. Children, especially those of school age (i.e. <18 years), need to be monitored carefully and follow mitigation strategies (e.g. social distancing, hand hygiene, wearing face masks) to prevent asymptomatic community transmission of COVID-19.
Topics: Adult; Asymptomatic Infections; COVID-19; Child; Humans; Quarantine; Retrospective Studies; SARS-CoV-2
PubMed: 35038628
DOI: 10.1016/j.puhe.2021.12.003 -
Pathogens and Global Health Dec 2022Presently in India, high endemic zones of malaria are shifting towards low endemic zones and in this changing scenario, tackling the asymptomatic and low-density...
Presently in India, high endemic zones of malaria are shifting towards low endemic zones and in this changing scenario, tackling the asymptomatic and low-density infections (LDI) would be an important factor. Role of the asymptomatic and LDI in transmitting parasites successfully to mosquito vectors needs to be systematically investigated. We here highlight the limited work done on the burden of asymptomatic Plasmodium infections in India with an emphasis on its infectiousness, and infrastructure available for the detection of LDI. Studies reporting the threshold of gametocytes required for transmission of parasites are lacking for Indian malaria vectors. In the wake of malaria elimination target by 2030, specific point of care test is required to be developed for the detection of low density infections and/or asymptomatic patients. Also, mapping of asymptomatic malaria burden pan India and the role of LDI in vector infectivity would guide the way forward in achieving malaria elimination goal in India.
Topics: Animals; Humans; Malaria, Falciparum; Plasmodium falciparum; Malaria; Mosquito Vectors; India; Asymptomatic Infections
PubMed: 35979713
DOI: 10.1080/20477724.2022.2113304 -
Cancer Radiotherapie : Journal de La... Oct 2020
Topics: Asymptomatic Infections; COVID-19; COVID-19 Nucleic Acid Testing; France; Humans; Incidence; Radiography, Thoracic; Radiotherapy; Reverse Transcriptase Polymerase Chain Reaction; SARS-CoV-2
PubMed: 33518226
DOI: 10.1016/j.canrad.2020.08.006 -
Canadian Journal of Anaesthesia =... Oct 2020Risk to healthcare workers treating asymptomatic patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the operating room depends on... (Review)
Review
PURPOSE
Risk to healthcare workers treating asymptomatic patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the operating room depends on multiple factors. This review examines the evidence for asymptomatic or pre-symptomatic carriage of SARS-CoV-2, the risk of transmission from asymptomatic patients, and the specific risks associated with aerosol-generating procedures. Protective measures, such as minimization of aerosols and use of personal protective equipment in the setting of treating asymptomatic patients, are also reviewed.
SOURCE
We examined the published literature as well as Societal guidelines.
PRINCIPAL FINDINGS
There is evidence that a proportion of those infected with SARS-CoV-2 have detectable viral loads prior to exhibiting symptoms, or without ever developing symptoms. The degree of risk of transmission from asymptomatic patients to healthcare providers will depend on the prevalence of disease in the population, which is difficult to assess without widespread population screening. Aerosol-generating procedures increase the odds of viral transmission from infected symptomatic patients to healthcare providers, but transmission from asymptomatic patients has not been reported. Techniques to minimize aerosolization and appropriate personal protective equipment may help reduce the risk to healthcare workers in the operating room. Some societal guidelines recommend the use of airborne precautions during aerosol-generating procedures on asymptomatic patients during the coronavirus disease pandemic, although evidence supporting this practice is limited.
CONCLUSION
Viral transmission from patients exhibiting no symptoms in the operating room is plausible and efforts to reduce risk to healthcare providers include reducing aerosolization and wearing appropriate personal protective equipment, the feasibility of which will vary based on geographic risk and equipment availability.
Topics: Aerosols; Asymptomatic Infections; Betacoronavirus; COVID-19; Carrier State; Coronavirus Infections; Health Personnel; Humans; Infectious Disease Transmission, Patient-to-Professional; Pandemics; Personal Protective Equipment; Pneumonia, Viral; SARS-CoV-2
PubMed: 32488493
DOI: 10.1007/s12630-020-01729-x