Cet article fait partie d’une série de notes explicatives sur la mise au point et la distribution de vaccins.
Vertreter besorgniserregender Virusvarianten (variants of concern, kurz VOC) wurden weltweit aber auch in Europa, identifiziert. Molekularbiologische Details zu den Varianten sind unter SARS-CoV-2: Virologische Basisdaten und Virusvarianten abrufbar.
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.
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.
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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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.
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
PLEASE download the article from the website!!
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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Given the circulation of the variant of clade I of mpox virus (MPXV) in the African Region, which is associated in the African Region with sustained transmission and the occurrence of cases in a wider range of age groups, including children, the Pan American Health Organization/World Health Organiza...tion (PAHO/WHO) encourages Member States to remain vigilant to the possibility of introduction of this variant in the Americas, and to continue their surveillance efforts, including genomic sequencing of detected cases, with special emphasis on high-risk groups.
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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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Mpox is an emerging zoonotic disease caused by the mpox virus, a member of the Orthopoxvirus genus closely related to the variola virus that causes smallpox. Mpox was first discovered in 1958 when outbreaks of a pox-like disease occurred in monkeys kept for research. The first human case was recorde...d in 1970 in the Democratic Republic of the Congo (DRC) during a period of intensified effort to eliminate smallpox and since then the infection has been reported in a number of African countries. Mpox can spread in humans through close contact, usually skin-to-skin contact, including sexual contact, with an infected person or animal, as well as with materials contaminated with the virus such as clothing, beddings and towels, and respiratory droplets in prolonged face to face contact. People remain infectious from the onset of symptoms until all the lesions have scabbed and healed. The virus may spread from infected animals through handling infected meat or through bites or scratches. Diagnosis is confirmed by polymerase chain reaction (PCR) testing of material from a lesion for the virus’s DNA. Two separate clades of the mpox virus are currently circulating in Africa: Clade I, which includes subclades Ia and Ib, and Clade II, comprising subclades IIa and IIb. Clade Ia and Clade Ib have been associated with ongoing human-to-human transmission and are presently responsible for outbreaks in the Democratic Republic of the Congo (DRC), while Clade Ib is also contributing to outbreaks in Burundi and other countries.
In 2022‒2023 mpox caused a global outbreak in over 110 countries, most of which had no previous history of the disease, primarily driven by human-to-human transmission of clade II through sexual contact. In just over a year, over 90,000 cases and 150 deaths were reported to the WHO. For the second time since 2022, mpox has been declared a global health emergency as the virus spreads rapidly across the African continent. On 13 Aug 2024, Africa CDC declared the ongoing mpox outbreak a Public Health Emergency of Continental Security (PHECS), marking the first such declaration by the agency since its inception in 2017.7 This declaration empowered the Africa CDC to lead and coordinate responses to the mpox outbreak across affected African countries. On August 14, 2024, the WHO declared the resurgence of mpox a Public Health Emergency of International Concern (PHEIC) emphasizing the need for coordinated international response.
As of August 2024, Mpox has expanded beyond its traditional endemic regions, with new cases reported in countries including Sweden, Thailand, the Philippines, and Pakistan. Sweden has confirmed its first case of Clade 1 variant, which has been rapidly spreading in Africa, particularly in DRC. The emergence of this new variant raises concerns about its potential for higher lethality and transmission rates outside Africa.
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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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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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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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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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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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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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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.
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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