Weekly epidemiological update on COVID-19, 28 September 2022
21 January 2022
The overall threat posed by Omicron largely depends on four key questions: (i) how transmissible the variant is; (ii) how well vaccines and prior infection protect against infection, transmission, clinical disease and death; (iii) how virulent the variant is compared to other varian...ts; and (iv) how populations understand these dynamics, perceive risk and follow control measures, including public health and social measures (PHSM).
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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.
Contact tracing for COVID-19 is the process of identifying, assessing, and managing people who have been exposed to someone who has been infected with the SARS-CoV-2 virus, while quarantine is the separation of contacts from other people after exposure to a probable or confirmed case of SARS-CoV-2 i...nfection. In the context of growing global population immunity from COVID-19 vaccination and past SARS-CoV-2 infection, WHO recommends that identification, contact, quarantine and follow-up should be prioritized for individuals at high risk who have been in contact with a confirmed or probable case of SARS-CoV-2 infection, rather than targeting all contacts. This updated guidance also introduces shorter recommended quarantine periods, including the ability to further shorten quarantine through the use of testing. National and local health authorities should use risk-based approaches to contact tracing and quarantine that include reviewing and adjusting to their local circumstances and disease epidemiology, population immunity, their health system’s capacities, and risk tolerance.
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Strengthening surveillance for Variant of Concern (VOC) Omicron (B.1.1.529): technical brief and priority actions for member states World Health Organization Headquarters, 28 November 2021
Wearing a face mask can help reduce the spread of COVID-19 in the community by reducing the release of respiratory droplets from asymptomatic / pre-symptomatic individuals or those with mild non-specific symptoms. The use of face masks for this purpose may be adopted to reduce the societal impact as...sociated with absence from work or healthcare pressures due to infection, or to protect vulnerable individuals in particular settings.
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22 April 2022, This document provides updated interim recommendations on the use of masks by health workers providing care to patients with suspected or confirmed COVID-19. This update is prompted by new evidence around mask use and COVID-19 transmission, as well as the emergence of variants of conc...ern including Omicron. Masks continue to be a critical tool to prevent the spread of COVID-19. These interim guidelines supersede the recommendations provided in the WHO recommendations on mask use by health workers, in light of the Omicron variant of concern published on 22 December 2022.
WHO continually evaluates the emerging evidence and will review these interim recommendations within two months and issue new guidance as needed.
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This document aims to provide interim guidance for microbiology and virology experts, other laboratory professionals, laboratory managers, infectious disease programme managers, public health professionals and other stakeholders that provide primary, confirmatory or advanced testing for SARS-CoV-2, ...including genomic sequencing, or are involved in making decisions on establishing or scaling up capability and capacity to detect and characterize circulating SARS-CoV-2 variants.
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This series of supportive tools are based on the WHO Therapeutics and COVID-19: living guideline. They are intended to provide supportive information for healthcare workers who are prescribing, administering and monitoring patients receiving nirmatrelvir-ritonavir for non-severe COVID-19.
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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Declarations of interests were collected from all external contributors and assessed for any conflicts of interest. Summaries of the reported interests can be found on the SAGE meeting website and SAGE Covid-19 Working Group webpage. This guidance should be considered along with the broader COVID-...19 policy advice to WHO member states and in particular the advice on how to reach the COVID-19 vaccination targets.
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Globally, more than 3 million new cases and 10 000 deaths have been reported in the week of 26 December 2022 to 1 January 2023. This represents a reduction in weekly cases and deaths of 22% and 12%, respectively. In the last 28 days (5 December 2022 to 1 January 2023), over 14.5 million cases and ov...er 46 000 new fatalities were reported globally – an increase of 25% and 21%, respectively, compared to the previous 28 days. As of 1 January 2023, over 656 million confirmed cases and over 6.6 million deaths have been reported globally.
In this edition, we include:
The COVID-19 epidemiological update at the global and regional levels.
An update on the circulating SARS-CoV-2 variants of concern (VOCs) and Omicron subvariants under monitoring.
An update on hospitalizations and ICU admissions related to COVID-19.
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As of 12 December 2022, over 645 million people worldwide have been diagnosed with COVID-19, with over 6.6 million deaths (4).
The Omicron variant, which emerged in late November 2021, and its subvariants, are now the dominant circulating viruses, contributing to the ongoing surge in several countr...ies (4). Vaccination has substantially reduced case numbers and hospitalizations in many countries,but limitations in global access to vaccines mean that many populations, including those in low- and middle-income countries, remain vulnerable. Even in vaccinated individuals, uncertainties remain about duration of protection and efficacy, and the degree of crossprotection with new variants.
There remains a need for more effective treatment and management for those affected by COVID-19. The pandemic – and the
explosion of both research and misinformation – has highlighted the need for trustworthy, accessible and regularly updated living
guidelines to place emerging findings into context and provide clear recommendations for clinical practice
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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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