The New England Journal of Medicine
Genetic analysis of the virus indicates that it is closely related (97% identical) to variants of Ebola virus (species Zaire ebolavirus) identified earlier in the Democratic Republic of the Congo and Gabon
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Weekly epidemiological update on COVID-19, 28 September 2022
1 March 2021
This article is part of a series of explainers on vaccine development and distribution. Learn more about vaccines – from how they work and how they’re made to ensuring safety and equitable access – in WHO’s Vaccines Explained series.
As new variants emerge people are wondering if they should wait until a more efficacious vaccine is available or if they should go ahead and get vaccinated now? Answering your questions on COVID-19 vaccines and variants in this episode of Science in 5 is WHO's Dr Soumya Swaminathan.
The NY Times variant tracker is perhaps the most accessible and relevant publication for non-molecular biologists and the general public
Each coronavirus contains nearly 30,000 letters of RNA. This genetic information allows the virus to infect cells and hijack them to make new viruses.
26 March 2021
If you have already had COVID-19 do you still need both doses of the vaccine? Do these vaccines protect you against infection? Do they protect us against variants? WHO’s Dr Katherine O’Brien answers these questions in Science in 5 this week.
n light of the potential risk posed by SARS-CoV-2 variants, in January 2021 WHO organized an ad hoc consultation to discuss the development of an R&D agenda in response to existing and emerging SARS-CoV-2 variants.
The key objectives were to identify the critical research questions related to var...iants and agree on a research approach to address them. Six breakout groups covered a range of specific issues related to COVID-19 variants: Epidemiology and mathematical modelling; evolutionary biology; animal models; assays and diagnostics; clinical management and therapeutics; and vaccines.
This report is a summary of presentations and panel discussions.
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Orientations provisoires, 28 janvier 2021
Dans cette version mise à jour des orientations sur la sécurité biologique en laboratoire en rapport avec le SARS-CoV-2, le virus responsable de la maladie à coronavirus 2019 (COVID-19), les points suivants ont été ajoutés : aspects de... sécurité biologique relatifs à la réalisation des tests diagnostiques rapides antigéniques, manipulation des nouveaux variants du SARS-CoV-2 au laboratoire, mise à jour de la décontamination des tests avant leur élimination, équipement de protection individuelle (EPI) pour le prélèvement d’échantillons et, même s’ils ne concernent pas directement la sécurité biologique, dangers chimiques et leur élimination en toute sécurité.
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What are the variants circulating at this time? How are variants classified as variants of interest or concern? What does this mean for the public? Dr Maria Van Kerkhove explains in Science in 5 this week.
Countries across the world are facing diverse epidemiological situations with varying response
capacities and access to life saving tools. The World Health Organization (WHO) recommends that national authorities continue to apply a risk-based approach when implementing measures related to COVID-19... and international travel while respecting the dignity, human rights and fundamental freedoms of travellers. This approach should consider the risk posed by travel for the importation and exportation of cases in the context of the evolving epidemiology, including the emergence and circulation of virus variants of concern; the expansion of the COVID-19 vaccination roll-out; and lessons learned while responding to the pandemic, including on the early detection and management of cases and the application of public health and social measures.
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Cet article fait partie d’une série de notes explicatives sur la mise au point et la distribution de vaccins.
Lorsqu’un virus circule largement dans une population et entraîne de nombreuses infections, la probabilité de mutation augmente. Plus un virus a de possibilités de se propager, plus il se réplique – et plus il est susceptible de muter. L’arrêt de la propagation du virus à la source res...te essentiel. Les mesures actuelles visant à réduire la transmission du virus – dont le lavage fréquent des mains, le port du masque, la distanciation physique et le fait d’éviter de se rendre dans les lieux très fréquentés ou fermés – restent efficaces contre les nouveaux variants car elles réduisent la transmission du virus, qui a donc moins de possibilités de muter. Grâce aux notes explicatives de l’OMS sur les vaccins, en savoir plus sur les vaccins, sur leur fonctionnement et sur la façon dont ils sont fabriqués pour en garantir l’innocuité et y permettre un accès équitable.
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What do we know about Omicron variant so far? WHO's Dr Maria Van Kerkhove updates on the transmissibility, severity, symptoms and ways to protect yourself in Science in 5.
If Omicron is less severe, why are people ending up in the hospital and dying from it? Is it true that everyone will eventually get Omicron? Why is it important to reduce transmission? WHO's Dr Maria Van Kerkhove explains in Science in 5.
n response to the outbreak, the Africa Centres for Disease Control and Prevention (Africa CDC) has been supporting African Union Member States in responding to the COVID-19 pandemic through a variety of interventions such as non-pharmaceutical interventions, quarantine, testing, isolation, contact t...racing, and clinical management. The Test to Treat guideline aims to increase continental testing efforts and reduce COVID-19 transmission in Africa and put-up response measures to control the impact of the virus, both to limit spread and to reduce substantially the risks of severe health outcomes related to COVID-19 infection. These countermeasures include highly effective vaccines and boosters, rapid testing options for monitoring exposure, and effective therapeutic options for both pre-exposure prevention and treatment of mild-to-moderate disease, oxygen therapy for moderate-severe disease, all of which can potentially be updated efficiently as new variants emerge that may affect the effectiveness of the available tools.
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While COVID-19 virus continues to circulate and evolve, new variants are constantly emerging. Most of the current COVID-19 cases are driven by the circulation of the BA.5 subvariant of Omicron. The COVID-19 vaccines are being updated with Omicron variants to provide broader immunity against circulat...ing and emerging variants.
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Dengue is the fastest spreading, mosquito-borne viral infectious disease worldwide, with remarkable morbidity and mortality. In the past decades, profound contributions have been made towards understanding its epidemiology, including disease burden and distributions, risk factors, and control and pr...evention practices. Dengue continues to disseminate to new areas, including high latitude regions, and a new serotype (dengue virus serotype 5) has been identified. Vaccine research has made new progress, in which the licensed yellow fever and dengue virus quadrivalent chimeric vaccine is now under further safety assessment. In disease surveillance, because of its operational simplicity, rapidity, capability, and utility as an indicator of disease severity, dengue virus NS1 antigen detection has great promotion and application value among primary health care institutions. Vector control progress has driven new breakthroughs in biotechnology, including Wolbachia-infected Aedes and genetically modified Aedes. Both Aedes variants have been used to block transmission of the dengue virus through population replacement and suppression. In the future, vector control should still be pursued as a key measure to prevent transmission, along with anti-viral drug and vaccine research.
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The WHO continuously reviews available data on SARS-CoV-2 variants of concern. For this version, the global epidemiological
situation of the COVID-19 pandemic as of 21 January 2022 – at a time when the Omicron VOC had been identified in 171
countries across all six WHO Regions and was rapidly re...placing Delta worldwide – was considered Omicron has a substantial growth advantage, higher secondary attack rates and a higher observed reproduction number than Delta.
There is now significant evidence that immune evasion contributes to the rapid spread of Omicron. Other factors may be a shorter
serial interval (by about 0.8 to 1.2 days compared to Delta) and potential increased intrinsic transmission fitness . There is
growing evidence that with Omicron, there is lower vaccine effectiveness (VE) against infection and symptomatic disease soon after vaccination compared to Delta. There is also evidence of accelerated waning of VE over time of the primary series against infection and symptomatic disease for the studied vaccines. Further studies are required to better understand the drivers of transmission and declining incidence in various settings. These factors include the intrinsic transmission fitness properties of the virus, degree of immune evasion, vaccination coverage and level of vaccine-derived and post-infection immunity, levels of social mixing and degree of application of public health and social measures (PHSM).
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Rabies is a fatal viral zoonosis and serious public health problem.1 All mammals are believed to be susceptible to the disease, and for the purposes of this document, use of the term animal refers to mammals. The disease is an acute, progressive encephalitis caused by viruses in the genus Lyssavirus....
2 Rabies virus is the most important lyssavirus globally. In the
United States, multiple rabies virus variants are maintained in wild mammalian reservoir populations such as raccoons, skunks, foxes, and bats. Although the United States has been declared free from transmission of canine rabies virus variants, there is always a risk of reintroduction of these variants.The rabies virus is usually transmitted from animal to animal through bites. The incubation period is
highly variable. In domestic animals, it is generally 3 to 12 weeks, but can range from several days to months, exceeding 6 months.8 Rabies is communicable during the period of salivary shedding of rabies virus. Experimental and historic evidence documents that dogs, cats, and ferrets shed the virus for a few days prior to the onset of clinical signs and during illness. Clinical signs of rabies are variable and include inappetance, dysphagia, cranial nerve deficits, abnormal behavior, ataxia, paralysis, altered vocalization, and seizures. Progression to death is rapid. There are currently no known effective rabies antiviral drugs.
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WHO has updated its guidelines for COVID-19 therapeutics, with revised recommendations for patients with non-severe COVID-19. This is the 13th update to these guidelines.
Updated risk rates for hospital admission in patients with non-severe COVID-19
The guidance includes updated risk rates for... hospital admission in patients with non-severe COVID-19.
The current COVID-19 virus variants tend to cause less severe disease while immunity levels are higher due to vaccination, leading to lower risks of severe illness and death for most patients.
This update includes new baseline risk estimates for hospital admission in patients with non-severe COVID-19. The new ‘moderate risk’ category now includes people previously considered to be high risk including older people and/or those with chronic conditions, disabilities, and comorbidities of chronic disease. The updated risk estimates will assist healthcare professionals to identify individuals at high, moderate or low risk of hospital admission, and to tailor treatment according to WHO guidelines:
**High: **People who are immunosuppressed remain at higher risk if they contract COVID-19, with an estimated hospitalization rate of 6%.
**Moderate: **People over 65 years old, those with conditions like obesity, diabetes and/or chronic conditions including chronic obstructive pulmonary disease, kidney or liver disease, cancer, people with disabilities and those with comorbidities of chronic disease are at moderate risk, with an estimated hospitalization rate of 3%.
Low: Those who are not in the high or moderate risk categories are at low risk of hospitalization (0.5%). Most people are low risk.
Review of COVID-19 treatments for people with non-severe COVID-19
WHO continues to strongly recommend nirmatrelvir-ritonavir (also known by its brand name ‘Paxlovid’) for people at high-risk and moderate risk of hospitalization. The recommendations state that nirmatrelvir-ritonavir is considered the best choice for most eligible patients, given its therapeutic benefits, ease of administration and fewer concerns about potential harms. Nirmatrelvir-ritonavir was first recommended by WHO in April 2022.
If nirmatrelvir-ritonavir is not available to patients at high-risk of hospitalization, WHO suggests the use of molnupiravir or remdesivir instead.
WHO suggests against the use of molnupiravir and remdesivir for patients at moderate risk, judging the potential harms to outweigh the limited benefits in patients at moderate risk of hospital admission.
For people at low risk of hospitalization, WHO does not recommend any antiviral therapy. Symptoms like fever and pain can continue to be managed with analgesics like paracetamol.
WHO also recommends against use of a new antiviral (VV116) for patients, except in clinical trials.
The update also includes a strong recommendation against the use of ivermectin for patients with non-severe COVID-19. WHO continues to advise that in patients with severe or critical COVID-19, ivermectin should only be used in clinical trials.
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