Your browser doesn't support javascript.
Show: 20 | 50 | 100
Results 1 - 10 de 10
BMJ ; 375: n3105, 2021 12 20.
Article in English | MEDLINE | ID: covidwho-1597444
Preprint in English | EuropePMC | ID: ppcovidwho-295480


The SARS-CoV-2 Delta variant transmits much more rapidly than prior SARS-CoV-2 viruses. The primary mode of transmission is via short range aerosols that are emitted from the respiratory tract of an index case. There is marked heterogeneity in the spread of this virus, with 10-20% of index cases contributing to 80% of secondary cases while most index cases have no subsequent transmissions. Vaccination, ventilation, masking, eye protection, and rapid case identification with contact tracing and isolation can all reduce transmission of this virus.

Ann Intern Med ; 174(7): 1037, 2021 07.
Article in English | MEDLINE | ID: covidwho-1526991

COVID-19 , SARS-CoV-2 , Humans
Ann Intern Med ; 174(1): 69-79, 2021 01.
Article in English | MEDLINE | ID: covidwho-1067970


Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the etiologic agent of coronavirus disease 2019 (COVID-19), has spread globally in a few short months. Substantial evidence now supports preliminary conclusions about transmission that can inform rational, evidence-based policies and reduce misinformation on this critical topic. This article presents a comprehensive review of the evidence on transmission of this virus. Although several experimental studies have cultured live virus from aerosols and surfaces hours after inoculation, the real-world studies that detect viral RNA in the environment report very low levels, and few have isolated viable virus. Strong evidence from case and cluster reports indicates that respiratory transmission is dominant, with proximity and ventilation being key determinants of transmission risk. In the few cases where direct contact or fomite transmission is presumed, respiratory transmission has not been completely excluded. Infectiousness peaks around a day before symptom onset and declines within a week of symptom onset, and no late linked transmissions (after a patient has had symptoms for about a week) have been documented. The virus has heterogeneous transmission dynamics: Most persons do not transmit virus, whereas some cause many secondary cases in transmission clusters called "superspreading events." Evidence-based policies and practices should incorporate the accumulating knowledge about transmission of SARS-CoV-2 to help educate the public and slow the spread of this virus.

COVID-19/transmission , SARS-CoV-2/isolation & purification , Aerosols , Equipment Contamination , Fomites/virology , Humans , RNA, Viral/analysis , Risk Factors
Antimicrob Agents Chemother ; 65(1)2020 12 16.
Article in English | MEDLINE | ID: covidwho-991744


Remdesivir was recently approved by the Food and Drug Administration for the treatment of hospitalized patients with coronavirus disease 2019 (COVID-19). Remdesivir is the prodrug of an adenosine analogue that inhibits viral replication of several RNA virus families, including Coronaviridae Preclinical data in animal models of coronavirus diseases, including COVID-19, have demonstrated that early treatment with remdesivir leads to improved survival, decreased lung injury, and decreased levels of viral RNA. Recent clinical data have demonstrated the clinical activity of remdesivir in terms of faster time to recovery in patients with severe COVID-19 and higher odds of improved clinical status in patients with moderate COVID-19. Here, clinical trials published to date are presented and appraised. Remdesivir's potential benefits and its favorable adverse-event profile make it an option for the treatment of COVID-19. This article examines the available literature describing remdesivir's pharmacology, pharmacokinetics, and preclinical and clinical data.

Adenosine Monophosphate/analogs & derivatives , Alanine/analogs & derivatives , Antiviral Agents/administration & dosage , Antiviral Agents/pharmacology , COVID-19/drug therapy , Adenosine Monophosphate/administration & dosage , Adenosine Monophosphate/chemistry , Adenosine Monophosphate/pharmacokinetics , Adenosine Monophosphate/pharmacology , Alanine/administration & dosage , Alanine/chemistry , Alanine/pharmacokinetics , Alanine/pharmacology , Animals , Antiviral Agents/chemistry , Antiviral Agents/pharmacokinetics , Breast Feeding , Clinical Trials as Topic , Coronavirus Infections/drug therapy , Coronavirus Infections/prevention & control , Female , Humans , Immunocompromised Host , Middle East Respiratory Syndrome Coronavirus/drug effects , Pregnancy , SARS-CoV-2/drug effects , SARS-CoV-2/genetics
Lancet Infect Dis ; 21(6): e163-e169, 2021 06.
Article in English | MEDLINE | ID: covidwho-960192


People with persistently asymptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection experience no symptoms throughout the course of infection, and pre-symptomatic individuals become infectious days before they report symptoms. Transmission of SARS-CoV-2 from individuals without symptoms contributes to pandemic spread, but the extent of transmission from persistently asymptomatic individuals remains unknown. We describe three methodological issues that hinder attempts to estimate this proportion. First, incomplete symptom assessment probably overestimates the asymptomatic fraction. Second, studies with inadequate follow-up misclassify pre-symptomatic individuals. Third, serological studies might identify people with previously unrecognised infection, but reliance on poorly defined antibody responses and retrospective symptom assessment might result in misclassification. We provide recommendations regarding definitions, detection, documentation, and follow-up to improve the identification and evaluation of people with persistently asymptomatic SARS-CoV-2 infection and their contacts. Accurate characterisation of the persistently asymptomatic fraction of infected individuals might shed light on COVID-19 pathogenesis and transmission dynamics, and inform public health responses.

Asymptomatic Infections , COVID-19 , Asymptomatic Infections/epidemiology , COVID-19/diagnosis , COVID-19/epidemiology , COVID-19/transmission , Humans , Pandemics , Retrospective Studies , SARS-CoV-2 , Serologic Tests