COVID-19 Variant: NIMBUS AHEAD?

The new COVID-19 variant, NB.1.8.1 or “Nimbus” has gained global attention and triggered local monitoring efforts. Should we be concerned?

GLOBAL CASES RISE AND LOCAL VIGILANCE GROWS
In June 2025, Health Minister Dr. Aaron Motsoaledi addressed the media regarding the emergence of the new COVID-19 variant, Nimbus. Citing data from the
National Institute for Communicable Diseases (NICD), he confirmed that no cases of Nimbus had been detected in South Africa as of 10 June. He further  reassured the public that the country’s strong surveillance systems would detect and swiftly respond to any local cases.
(1) (2) (3)

Globally, Nimbus was first identified in Asia in January 2025 and soon gained momentum. By April it accounted for over 10% of laboratory-confirmed COVID-19 cases. In May, the World Health Organisation (WHO) classified it as a “Variant Under Monitoring”, although deeming the public health risk as “low”.
Nevertheless, the variant continues to spread across multiple international regions, with notable surges reported in India, Taiwan, and the United States – where
it accounted for 37% of COVID-19 cases in early June.
(4) (2) (5) (6) (7)

KEY INSIGHTS INTO NIMBUS
Nimbus is a subvariant of Omicron with subtle genetic differences that have been reported to contribute to its faster spread. Despite these differences, it still
shares many similar traits with earlier strains and is not currently associated with more severe illness. Symptoms are generally mild and affect the upper respiratory tract (sharp sore throat, nasal congestion, dry cough), along with fever, muscle aches, and fatigue. While current COVID-19 vaccines may be slightly less effective at preventing infection, they still offer protection against severe illness and hospitalisation, owing to the broad immune response they trigger.

In South Africa, there is no immediate need for concern. Trends show low COVID-19 activity and no reports of the Nimbus variant. Although highly transmissible, it hasn’t been linked to more severe illness. Local surveillance remains active, especially during the winter rise in respiratory infections (like influenza).

As symptoms often overlap and not all cases are laboratory confirmed, the same prevention measures apply – cover mouth and nose when coughing or sneezing,
wash hands regularly, and maintain good overall hygiene. (2) FOR MORE INFORMATION, VISIT THE NICD WEBSITE: www.nicd.ac.za NICD reports that there is currently no local supply of any COVID-19 vaccines. Further updates will be shared as available

References
1.
National Institute for Communicable Diseases. (2025, June 10). Weekly respiratory pathogens surveillance report.
https://www.nicd.ac.za/diseases-a-z-index/disease-index-covid-19/surveillance-reports/weekly-respiratory-pathogenssurveillance-report-week/.
2. National Institute for Communicable Diseases. (2025, June 10). COVID-19 update: Latest on SARS-CoV-2 variant NB.1.8.1.
https://www.nicd.ac.za/covid-19-update-latest-on-sars-cov-2-variant-nb-1-8-1-june-2025/.
3. Motsoaledi, A. (2025, June 12). Fourth Health Working Group Meeting of the G20: Remarks on NB.1.8.1 COVID-19 variant. SA Government.
https://www.gov.za/news/speeches/minister-aaron-motsoaledi-fourth-health-working-group-meeting-southafrican-g20.
4. World Health Organization. (2025, May 23). Risk evaluation for SARS-CoV-2 Variant Under Monitoring: NB.1.8.1. https://
www.who.int/publications/m/item/risk-evaluation-for-sars-cov-2-variant-under-monitoring-nb.1.8.1.
5. Health.com. (2025, June). New COVID Variant NB.1.8.1 Detected in the U.S.—What to Know. https://www.health.com/newcovid-variant-nb-181-11744062[3] (https://www.health.com/new-covid-variant-nb-181-11744062).
6. GISAID. (2025). hCoV-19 Variants. https://gisaid.org/hcov19-variants/[1](https://gisaid.org/hcov19-variants/).
7.
Centers for Disease Control and Prevention. (2025, June 13). Respiratory Illnesses Data Channel. https://www.cdc.gov/respiratory-viruses/data/index.htm.
8. Geddes, L. (2025, June 16). Eight things you need to know about the new “Nimbus” and “Stratus” COVID-19 variants.
Vaccines Work. Retrieved from https://www.gavi.org/vaccineswork/eight-things-you-need-know-about-new-nimbus-andstratus-covid-variants.
9. Life Medical. (2025, June 14). Nimbus COVID Variant: Key Facts and Updates. Life Medical Lab. Retrieved from
https://lifemedicallab.com/health/nimbus-covid-variant-key-facts-and-updates/.
10. COVID Nimbus. (2025). COVID-19 Nimbus Variant: Symptoms, Prevention & Latest Updates 2025. Retrieved from https://covidnimbus.com/