EXPLAINER: What is the COVID-19 Nimbus variant?

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The Nimbus variant, a descendant of the Omicron variant, may cause 'razor blade throat'

No, it’s not related to Harry Potter’s broomstick.

A new COVID-19 variant, NB.1.8.1, more commonly referred to as the Nimbus variant, is now making headlines as several countries report spikes in virus cases.

Here’s what you need to know:

What is the Nimbus variant?

The Nimbus variant, first reported in January, is a descendant of the Omicron variant.

The World Health Organization (WHO) designated it as a COVID variant under monitoring in May, but its global health risk is considered “low.”

“Despite a concurrent increase in cases and hospitalizations in some countries where NB.1.8.1 is widespread, current data do not indicate that this variant leads to more severe illness than other variants in circulation,” the WHO said in a risk evaluation report dated May 23.

While common COVID-19 symptoms would be present, reports have noted that the Nimbus variant may also cause “razor blade throat” or a painful sore throat.

But “currently approved COVID-19 vaccines are expected to remain effective to this variant against symptomatic and severe disease,” according to the WHO.

What’s the COVID-19 situation?

As of May 11, the WHO said the test positivity rate or the number of people testing positive for COVID-19 in 73 reporting countries and areas stood at 11%. More people were testing positive for the virus as the positivity rate of 110 reporting countries stood at only 2% in mid-February.

The increase in cases in May was driven by countries in the Eastern Mediterranean region, Southeast Asia, and the rest of the Western Pacific region.

The Nimbus variant accounted for 10.7% of global sequences in mid-May, which means that out of the total reported COVID-19 cases, around one-tenth were of the Nimbus variant. The WHO said Southeast Asia only had five Nimbus cases as of May 18.

As of June, however, more countries have reported a rise in COVID-19 cases.

The United States saw an increase in cases, and Nimbus is now its second most common COVID variant. The Nimbus variant accounted for an estimated 37% of COVID-19 cases logged in a two-week period that ended on June 7.

It is now also the most dominant COVID strain in the United Kingdom.

What is the situation in the Philippines?

The Department of Health (DOH) said it is monitoring the Nimbus variant. There haven’t been any reported local cases with this variant as of mid-June.

“We are monitoring our COVID cases kasi nga season natin ng (because it’s our season of) influenza-like illnesses, and COVID is one of those influenza-like illnesses,” Health Secretary Teodoro Herbosa said in a Palace briefing on Thursday, June 19.

“Mino-monitor po ng ating Epidemiology Bureau itong cases na ito (Our Epidemiology Bureau is monitoring these cases).”

From January 1 to June 7, 2025, the Philippines has recorded 2,760 COVID-19 cases nationwide. DOH spokesman Albert Domingo said this is 87% lower than the 21,867 cases logged in the same period in 2024. Note, however, that self-tests at home using rapid antigen kits have become common and such cases may not necessarily be reported to authorities, especially when they are mild.

The DOH reiterated that the public must practice standard health precautions like proper handwashing to prevent the spread of diseases. – Rappler.com