Recent data indicates a global increase in detected cases of the Nimbus (NB.1.8.1) and Stratus (XFG) COVID-19 variants. These variants are currently prevalent across regions including Asia, Europe, and the United States. Both exhibit high transmissibility and some degree of immune evasion. Nimbus, first identified in China in early 2025, has become a notable component of global case numbers, while Stratus demonstrates faster spread through immune escape mechanisms, despite being less efficient at cell entry than Nimbus.
For instance, the UK Health Security Agency (UKHSA) reports Stratus accounting for 63% and Nimbus for 25% of recent infections in the UK. Common symptoms associated with both variants, such as sore throat, cough, runny nose, fever, headache, and muscle aches, largely align with those of previous COVID-19 strains.
The World Health Organization (WHO) has not identified evidence suggesting increased severity for either variant compared to earlier strains, although mutations aiding immune evasion are present. However, individuals in vulnerable groups are noted to face heightened risk, and severe cases may necessitate hospitalization. In India, a limited number of cases have been reported, with experts assessing the variants as posing a comparable threat to previous iterations observed in the country.
Source: https://indianexpress.com/article/world/new-covid-variants-nimbus-and-stratus-drive-case-spikes-worldwide-10284795/