Recent COVID-19 variant 'Tracking Nimbus', Symptoms
- By Web Desk -
- Jun 20, 2025
A recent COVID-19 variant recently emerged in the U.S. ‘NB.1.8.1’, informally titled ‘Nimbus’, is attracting worldwide notice due to its fast spread and a particularly painful razor blade throat symptom, as described by patients.
According to the U.S. Centres for Disease Control and Prevention (CDC), COVID-19 variant B. 1.8.1 accounted for approximately 37% of all new infections in the United States during the two weeks ending June 7.
The World Health Organisation (WHO) has declared it a “variant under monitoring” due to its spike protein mutations and increasing worldwide occurrence.
Initially detected in China earlier this year, the variant has since been identified in over 22 countries, including India, where it is believed to be contributing to a recent uptick in cases.
In India, the National Institute of Virology (NIV) has isolated four Omicron subvariants LF.7, XFG, JN.1.16, and NB.1.8.1 (Nimbus), as part of ongoing genomic surveillance efforts.
Patients infected with the COVID-19 variant NB.1.8.1 commonly report symptoms such as nasal congestion, fatigue, mild cough, fever, body aches, and gastrointestinal issues.
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However, the standout symptom is the so-called razor blade throat symptom, which has been described as a sharp, stabbing pain when razor blade throat symptom starts occurring.
Despite its high transmissibility, current data suggests that NB.1.8.1 (Nimbus), does not cause more severe illness than previous variants. Vaccines are still expected to offer protection against serious outcomes, though health experts emphasize the importance of booster shots, especially for vulnerable populations.
In India, health authorities remain vigilant. Dr. Naveen Kumar, Director of NIV Pune, stated that genome sequencing is helping assess vaccine efficacy against emerging strains. “This effort will guide decisions on updating vaccine formulations, if necessary,” he said.
As summer travel and social gatherings increase, public health officials worldwide are urging continued caution, including mask-wearing in crowded spaces and staying up to date with vaccinations.The new COVID-19 variant NB.1.8.1, nicknamed ‘Nimbus’, is spreading rapidly in the US and Asia.