Why in News?
The variant NB.1.8.1 (Nimbus) is under the spotlight due to its unique ‘razor blade’ throat symptom and increasing global spread.
- Razor Blade variant – The variant is officially named NB.1.8.1, which is a descendant of the Omicron variant.
- The term "razor blade" comes from patients reporting an extremely painful sore throat, like “swallowing a razor blade.”
- WHO classification – On May 23, 2025, the World Health Organization (WHO) listed NB.1.8.1 as a Variant Under Monitoring (VUM).
A Variant Under Monitoring (VUM) is a term used to signal to public health authorities that a variant may require prioritized attention, monitoring and investigate if this variant may pose an additional threat to global public health.
- Existing COVID-19 vaccines are expected to remain effective against this variant for symptomatic and severe disease.
- Symptoms – Similar to other Covid variants,
- Fever
- Severe sore throat (razor-blade-like)
- Cough
- Runny nose
- Tiredness
- Current Global spread – NB.1.8.1 is increasing in proportion globally, while other variants like LP.8.1 are declining.
- It has shown higher transmissibility due to spike protein mutations.
- India’s situation – As of May 2025, 1 case of NB.1.8.1 was detected in Tamil Nadu and 4 cases of LF.7 were found in Gujarat.
- However, the dominant variant remains JN.1, comprising 53% of samples.
- A newer recombinant variant, XFG (Originated from two variants LF.7 + LP.81.2), has emerged since May 2025.
- Surveillance & genome sequencing – Genomic studies attribute recent surges to evolving Omicron sub-lineages.
- Severity and hospitalizations – So far, there is no evidence that NB.1.8.1 causes more severe disease than other circulating variants.
- Hospitalizations have increased in some countries, but not dramatically.
- Expert view in India – Indian doctors say COVID-19 is co-circulating with other seasonal infections and can expect spikes and dips, but no massive waves like in 2021.
- Recommended safety measures
- Hand hygiene
- Avoiding crowded places
- Wearing masks, especially in vulnerable populations
- Vaccination boosters as per national advisories
- Public health measures recommended – Continued emphasis on personal hygiene, masking in crowded areas, hand washing, and protecting the vulnerable population.
- The government advises vigilance but not panic, as health systems are better prepared.
Reference
The Hindu| Razor Blade Covid Variant
