The World Health Organization (WHO) is currently focusing on a new Covid-19 variant known as NB.1.8.1, or “Nimbus.”
Nimbus is a descendant of the Omicron variant and was first detected in late January.
According to the WHO, this variant seems to be more contagious compared to other Covid variants. The term “spike mutation” refers to alterations in the spike protein, which helps the virus attach to and enter healthy cells.
While cases of Nimbus are rising in the US and Canada, it hasn’t led to an uptick in severe illnesses or hospitalizations in those countries, nor in 20 other nations.
Back in April, NB.1.8.1 accounted for about 10.7% of all sequences from confirmed Covid infections, as stated in a WHO risk assessment.
Recently, WHO has categorized NB.1.8.1 as notable. So, what should you know about these variants?
Where are the US incidents?
Most Covid-19 cases in the US are still attributed to another Omicron subvariant, Lp.8.1. However, data from the Centers for Disease Control and Prevention (CDC) indicates that NB.1.8.1 may soon replace it as a more prevalent strain.
CDC estimates suggest that approximately 37% of US Covid-19 cases are due to NB.1.8.1, while 38% result from Lp.8.1. By the end of May, it was estimated that NB.1.8.1 caused about 15% of community cases.
Nevertheless, the agency emphasizes that the latest reporting might be incomplete due to a limited number of virus sequences available.
NB.1.8.1 has been detected in at least 13 states, with data from the global GISAID database indicating its spread. These states include California, New York, New Jersey, Maryland, Arizona, Illinois, Hawaii, Massachusetts, Ohio, Rhode Island, Vermont, Virginia, and Washington.
According to the WHO, current data suggests that the global threat posed by Nimbus is low, and that existing Covid-19 vaccines should adequately protect against severe illness and hospitalization.
The WHO risk assessment states, “The currently approved COVID-19 vaccine is expected to be effective against this variant for symptomatic and severe disease.” It also notes that even in some areas where NB.1.8.1 is prevalent, current data does not indicate it causes more severe illnesses compared to other circulating variants.
Lionel Gesh, an international consultant for WHO, mentioned that many recent cases in Canada are likely tied to the NB.1.8.1 variant, yet he pointed out that there hasn’t been a significant change in hospitalization rates, ICU admissions, or deaths related to Covid-19 in the country.
What are the symptoms?
As for the symptoms, Gesh stated that they appear to be quite similar to those linked to other Omicron variants.
Common Covid-19 symptoms reported by the CDC include cough, fever, fatigue, muscle pain, congestion, nausea, vomiting, and a new loss of smell and taste.
Interestingly, Gesh expressed concerns about Covid in general despite the relative stability of cases.
Some recent patients have mentioned a peculiar symptom termed “razor blade throat,” which has garnered attention.
However, it remains uncertain whether these symptoms are exclusive to this variant or if they overlap with other respiratory illnesses, as noted by Ryan Gregory, an evolutionary and genomic biologist at the University of Guelph in Canada.
