New Covid Variant ‘Nimbus’ Fuels Surge in Cases Across Asia
Global Health Officials Monitor Rising Infections and Potential Spread
A newly identified Covid-19 variant, dubbed NB.1.8.1 or “Nimbus,” is driving a resurgence of cases in multiple Asian countries, prompting health organizations worldwide to closely monitor its spread and potential impact.
Variant Characteristics and Transmission
The variant, a descendant of Omicron, has been detected in India, Thailand, China, Hong Kong, the UK, the US, and Australia. The World Health Organisation (WHO) has cautioned that NB.1.8.1 may be more transmissible
than earlier strains, increasing the ease with which it spreads between individuals.
India is currently experiencing a notable increase in Covid-19 cases. As of Monday, June 9th, the country reported 6,491 active cases, a rise from 5,364 on June 5th. The variant is now the dominant strain in both China and Hong Kong.
Regional Concerns and Government Responses
Authorities in Thailand have expressed concern that international travel could exacerbate rising infection rates and hospitalizations linked to the new variant, particularly following outbreaks in Bangkok and Chonburi Province. The Thai government is urging the public to adhere to established health guidelines.
According to the CDC, as of June 10, 2025, Covid-19 is currently ranked as the 11th leading cause of death in the United States. (CDC FastStats)
Situation in the United Kingdom
The UK Health Security Agency (UKHSA) has identified 13 cases of NB.1.8.1 in England, with a small number of additional cases detected elsewhere in the United Kingdom. Recent data indicates a slight increase in Covid-19 activity in England between May 26th and June 1st, with 1,124 cases recorded up to May 28th – a 10% increase from the previous week.
Weekly hospital admissions related to the virus have also seen a minor increase, rising to 1.49 per 100,000 patients, compared to 1.40 per 100,000 the prior week. Deaths linked to Covid-19 are up six percent, with 72 deaths recorded where the virus was mentioned on the death certificate in the week ending May 23rd.
“NB.1.8.1 has been detected in small numbers in the UK to date, but international data suggests that it is growing as a proportion of all COVID-19 cases. Based on the available information so far however, there is no evidence to suggest that this variant causes more severe disease than previous variants, or that the vaccines in current use will be less effective against it.”
—Dr. Gayatri Amirthalingam, UKHSA Deputy Director
Symptoms and Vaccination
Symptoms associated with the NB.1.8.1 variant appear to be consistent with previous iterations of the Covid-19 virus, particularly the Omicron variant, often manifesting as mild cold-like symptoms such as a runny nose and sore throat. Dr. Naveed Asif, a GP at The London General Practice, has noted a distinctive symptom: a severe sore throat described as a “razor blade sensation.”
Common symptoms, according to the National Health Service (NHS), include a high temperature, continuous cough, loss of smell or taste, shortness of breath, fatigue, body aches, headache, sore throat, nasal congestion, loss of appetite, nausea, vomiting, and diarrhea.
Health officials continue to emphasize the importance of vaccination as a key defense against the virus and its evolving variants. While the situation is being closely monitored, current vaccines are believed to offer continued protection against severe illness.
