COVID-19: What we know about the new NB.1.8.1 variant that the WHO is closely monitoring

A new Covid-19 variant, NB.1.8.1, is shaking global health authorities as it spreads rapidly across the g
1/12 Spread of the NB.1.8.1 variant in Asia
The NB.1.8.1 variant of Covid-19 emerged in China and spread rapidly across Asia, reaching regions such as Hong Kong where a significant rebound in the epidemic was observed. This sub-lineage of the Omicron variant, known for its high contagiousness, was classified by the World Health Organization (WHO) as a ‘variant under surveillance’ on May 23. This classification, created in 2020, is reserved for variants presenting an increased risk to public health.
2/12 Significant mutations of the NB.1.8.1
Professor Yves Buisson, a member of the National Academy of Medicine, pointed out that NB.1.8.1 has ‘three fairly significant mutations’ compared to its predecessor, which could make it the majority in the future. For his part, virologist Bruno Lina told BFMTV that the specificities of this variant could make it dominant. In Asia, particularly in Taiwan, the National Center for Disease reported a 66% increase in Covid-19 consultations in one week
3/12 Appearance of the NB.1.8.1 variant in Europe and the United States
In Europe, the NB.1.8.1 variant appeared in Germany, Ireland and the Netherlands, with France recording its first cases in March. According to the European Centre for Disease Prevention and Control (ECDC), the variant has been circulating since the beginning of April, but its epidemiological impact remains uncertain. In the United States, cases have been detected in international travelers arriving in several states, including California and New York.
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4/12 WHO reassures on the effectiveness of vaccines
The WHO has reassured the public that current Covid-19 vaccines should remain effective against this variant to prevent symptomatic and severe forms of the disease. However, it calls for vigilance, especially in Asia where the variant has become dominant. Hong Kong reported that key Covid-19 surveillance indicators were at their highest level in a year, prompting authorities to tighten hygiene measures.
5/12 Positive test rates increase in Hong Kong
The percentage of respiratory samples testing positive for SARS-CoV-2 in Hong Kong has doubled in a month, from 6.21% to 13.66%. In addition, the viral load in wastewater has almost doubled, reaching 710,000 copies/litre. Despite these alarming numbers, there is no indication at this time that NB.1.8.1 causes more severe forms of the disease.
6/12 Identification of the NB.1.8.1 variant in France and the United States
In France, the variant has been identified four times, according to the National Reference Center in Lyon. In the United States, travelers from European countries, including France, tested positive between the end of April and mid-May. The European Centre for Disease Prevention and Control has not yet placed the variant under surveillance, but is monitoring its evolution closely.
7/12 Low risk to public health but increased
transmissibility According to the WHO, the additional risk to public health posed by NB.1.8.1 is considered low globally. Nevertheless, the mutations observed could increase its transmissibility, which requires further studies. Scientists are concerned that these mutations could reduce the effectiveness of antibodies and promote immune evasion