Omicron update

On November 26, 2021. WHO has designated variant B.1.1.529 a cause for concern, called Omicron, on the advice of the WHO Technical Advisory Group on Virus Evolution (TAG-VE). This decision was based on the evidence presented by TAG-VE that Omicron has several mutations that can affect how it behaves, for example, how easily it spreads or the severity of the disease it causes. Here is a summary of what is currently known.

Current knowledge of Omicron

Researchers in South Africa and around the world are conducting studies to better understand many aspects of Omicron and will continue to share the findings of those studies as they become available.

Portability: It is not yet clear whether Omicron is more portable (e.g., easier to transmit from person to person) compared to other variants, including the Delta. The number of positive people has increased in the areas of South Africa affected by this variant, but epidemiological studies are underway to determine whether it is due to Omicron or other factors.

Severity of disease: It is not yet clear whether Omicron infection causes more severe disease compared to infections with other variants, including Delta. Preliminary data suggest an increase in hospitalization rates in South Africa, but this may be due to an increasing total number of people becoming infected and not due to a specific Omicron infection. There is currently no information to suggest that Omicron-related symptoms are different from those of the other variants. Initially reported infections were among students – younger people with a milder illness – but it will take a few days to a few weeks to understand the severity level of the Omicron variant. All variants of COVID-19, including the Delta variant that is dominant worldwide, can cause severe illness or death, especially for the most vulnerable people, so prevention is always key.

Efficacy of previous SARS-CoV-2 infection

Preliminary evidence suggests that there may be an increased risk of re-infection with Omicron (i.e. people who have previously had COVID-19 could be more easily re-infected with Omicron), compared to other variants of concern, but information is limited. More information on this will be available in the coming days and weeks.

Vaccine efficacy: WHO is working with technical partners to understand the potential impact of this variant on our existing countermeasures, including vaccines. Vaccines remain critical for reducing severe disease and death, including against the dominant circulating variant, Delta. Existing vaccines remain effective against serious illness and death.

Effectiveness of current tests: Widely used PCR tests continue to detect infection, including Omicron infection, as we have seen with other variants. Research is underway to determine if there is an impact on other types of tests, including tests for rapid detection of antigens.

The effectiveness of previous treatments: Corticosteroids and IL6 receptor blockers will continue to be effective in the treatment of patients with severe COVID-19. Other treatments will be evaluated to see if they are still equally effective with respect to changes in parts of the virus in the Omicron variant.

Studies are ongoing

Currently, the WHO is coordinating with a large number of researchers around the world to better understand Omicron. Ongoing or ongoing studies include assessment of transmission, severity of infection (including symptoms), efficacy of vaccines and diagnostic tests, and efficacy of treatment.

The WHO encourages countries to contribute to the collection and exchange of data on hospitalized patients through WHO COVID-19 Clinical Data Platform to quickly describe the clinical features and outcomes of the patient.

More information will appear in the coming days and weeks. The World Health Organization’s TAG-VE will continue to monitor and evaluate data as they become available and assess how mutations in Omicron change the behavior of the virus.

Recommended actions for countries

Since Omicron has been identified as a variant of concern, there are several actions that the WHO recommends to countries to take, including improving oversight and case order; sharing genome sequences in publicly available databases, such as GISAID; reporting initial cases or groups to the WHO; conducting field research and laboratory assessments to better understand whether Omicron has different transmission or disease characteristics or affects the effectiveness of vaccines, therapies, diagnostics, or public health and social issues. More details in Notice of 26 November.

Countries should continue to implement effective public health measures to reduce the overall circulation of COVID-19, using risk analysis and a science-based approach.. They should increase some public health and medical capacity to manage the increase in cases. The WHO provides countries with support and guidance for preparedness and response.

In addition, it is vital to address inequalities in access to COVID-19 vaccines as a matter of urgency to ensure that vulnerable groups everywhere, including health workers and the elderly, receive first and second doses, with equal access to treatment and diagnosis.

Recommended actions for people

The most effective steps that individuals can take to reduce the spread of the COVID-19 virus are to keep a physical distance of at least 1 meter from others; wear a mask that fits well; open windows to improve ventilation; avoid poorly ventilated or overcrowded spaces; keep your hands clean; cough or sneeze into a bent elbow or handkerchief; and get vaccinated when it’s their turn.

The WHO will continue to provide updates as more information becomes available, including the next TAG-VE meetings. In addition, information will be available on WHO digital and social media platforms.

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