The Centres for Disease Control and Prevention (CDC) have reported that a new and extremely contagious Covid-19 strain that caused a dramatic increase in hospitalisations throughout China has now been found in the United States.
The strain, known as NB.1.8.1, was initially discovered in the United States in late March and early April in foreign visitors arriving at airports in New York, California, Washington State, and Virginia. Since then, further cases have surfaced in Hawaii, Rhode Island, and Ohio.
Experts are concerned about the variant's quick spread in China and other parts of Asia, where it has already surpassed the prevalent strain, even though the number of confirmed cases in the US is still low.
According to the New York Post, health officials in Hong Kong recorded a notable increase in Covid-related hospitalisations and ER visits during the previous month, particularly among the elderly.
What is the new Covid variant?
According to the World Health Organisation (WHO), NB.1.8.1 is a SARS-CoV-2 strain that is being monitored and is becoming more prevalent worldwide. The agency is now tracking six of them.
The WHO reports that the first detection of NB.1.8.1 was made from samples taken in January 2025. It descends from the recombinant XDV lineage and is a sublineage of the Omicron variety.
Recombinant refers to the creation of a new variety through the genetic blending of two or more pre-existing variants.
The Covid vaccines that are currently authorised should continue to be effective against this variation and provide protection against serious illness.
While NB.1.8.1 does not seem to cause more severe sickness, it is spreading more quickly than previous variations, according to Dr Amy Edwards of Case Western Reserve University, who spoke to CBS News. “What they're seeing in China, Hong Kong, and elsewhere is a sharp uptick in hospitalisations”, she stated.
The variation was discovered as US health organisations updated their recommendations for the Covid-19 vaccine.
The CDC declared that booster doses will from now on only be administered to those at greatest risk, such as the elderly, and that it will no longer advise routine immunisation for healthy young people and pregnant women.
What are the symptoms?
The new strain's symptoms, which include fever, sore throat, cough and fatigue, are the same as earlier variations.
Gastrointestinal symptoms may also be seen in some cases.
According to specialists like Dr Subhash Verma of the University of Nevada, NB.1.8.1 seems to have a “growth advantage” that makes it easier to spread.
Where is it spreading?
It's found in 22 different nations. It has been linked to New York, California, Arizona, Ohio, and Rhode Island in the United States, according to documents from local health officials at Ginkgo Bioworks, CDC's airport testing partner.
The WHO reported a notable increase in its incidence from late March to April, although the numbers were still small.
In just four weeks, Hong Kong reported 81 severe cases and 30 deaths associated with the variation, the majority of which involved individuals 65 years of age and older.
In mainland China, the number of hospitalisations and the proportion of ER patients who test positive for Covid has more than doubled in recent weeks.
Chinese authorities have downplayed the variant's seriousness despite the surge, claiming it is not more harmful than earlier strains. However, US health authorities are still wary.
