What you need to know about Nimbus, the new COVID-19 variant
A new COVID-19 variant (NB.1.8.1 — unofficially nicknamed "Nimbus") is quietly crossing borders. First detected globally in January 2025, the variant has now been confirmed in over 20 countries, prompting the Directorate General of Health Services (DGHS) in Bangladesh to issue a nationwide alert.
Unlike in the early days of the pandemic, there are no frantic hospital scenes or mass testing queues. But experts warn that this new wave could be even harder to track, as it spreads with mild or no symptoms and very little public awareness.
For all latest news, follow The Daily Star's Google News channel. The NB.1.8.1 variant is a sub-lineage of Omicron, evolving as the virus continues to mutate. It was first identified in travellers from East Asia and Europe in January this year. Since then, it has spread quietly across several states in the US, UK, China, Australia, and now Bangladesh.
In China and Hong Kong, NB.1.8.1 has become the dominant strain. According to global health reports, the variant shows signs of increased transmissibility, meaning it may spread more easily from person to person than previous strains. And, one of the most unusual things about NB.1.8.1 is how quietly it spreads.
According to health officials, most people who test positive do not have the usual symptoms like fever or a persistent cough. Instead, they may feel a little tired, experience slight nasal congestion, or have a sore throat. Some have nausea and mild digestive issues like diarrhoea, and then carry on, unaware they have caught the virus. This makes detection especially difficult, and public awareness alarmingly low.
The DGHS's recent circular confirms that the variant is already present in Bangladesh and calls for renewed precautions, particularly at ports of entry, hospitals, and crowded public spaces.
The World Health Organization (WHO) has classified NB.1.8.1 as a "variant under monitoring," meaning it has not shown increased severity but is spreading quickly enough to warrant international attention.
Early studies suggest it may partially evade immunity from past infections or vaccinations. Yet, current vaccines and antiviral treatments remain effective in preventing severe illness.
The good news? There is no evidence so far that NB.1.8.1 or Nimbus is causing more hospitalisations or deaths than previous variants. However, health experts caution that its ability to spread silently could result in a slow and steady rise in cases if left unaddressed.
The DGHS has urged people to resume basic precautions. That includes wearing masks in crowded areas, washing hands regularly, staying home if unwell, and reporting any suspicious symptoms to local health authorities.
Healthcare workers are being reminded to prepare isolation facilities, resume the use of PPE, and screen travellers at airports, land borders, and seaports.
More than four years into the pandemic, public vigilance is understandably low. However, this variant is a reminder that the virus has not vanished; it has merely changed form. And it may be circulating in communities long before we recognise it.
NB.1.8.1 or Nimbus should prompt caution. As one health official noted: "This variant isn't loud. That's exactly why we need to listen."
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