New Covid variant NB.1.8.1 spreads across the continent amid calls for vigilance

The Global Virus Network (GVN) is closely monitoring the emergence of the newly identified SARS-COV-2 variant NB.1.8.1. The variant was first identified in January 2025 and spread rapidly to other regions, including across Asia and parts of the United States. The World Health Organization (WHO) has designated NB.1.8.1 as a supervised variant due to its increased prevalence and potential public health impacts. Based on current evidence, GVN recommends vigilance rather than vigilance, reinforcing the important role of vaccination in preventing severe illness and death.

Like previous Omicron subvarians, NB.1.8.1 contains spike protein mutations associated with increased permeability. However, there is no evidence that Nb.1.8.1 causes more severe illness or significantly avoids vaccine-induced or natural immunity. Early laboratory and clinical data show that an updated Covid-19 vaccine, including bivalent and XBB-based boosters, protects against serious consequences such as hospitalization and death. At this time, there is no evidence that NB.1.8.1 causes more severe illness than previous variants.

Groundbreaking infectious diseases can occur, especially among people with weakened immunity or unvaccinated. Nonetheless, vaccines are extremely effective in reducing serious illnesses and deaths. Antiviral treatments such as Nirmatrelvir/Ritonavir (Paxlovid) and Remdesivir have been shown Effectiveness For a variety of Omicron sub-variants, including BQ.1, BQ.1.1, and XBB.1.5.

NB.1.8.1 is associated with a significant increase in Covid-19 cases in several countries. According to the WHO, as of May 18, 2025, the NB.1.8.1 variant has been identified in 22 countries, accounting for 10.7% of the global SARS-COV-2 sequences submitted to the global initiative to share all influenza data (GISAID) during Epidemiology Week 17 (April 21-27, 2025) during Epidemiology Week (April 21-27, 2025). This is a significant increase from 2.5% four weeks ago.

As of June 4, 2025, India reported 4,302 active COVID-19 infections, with nearly 300 new cases recorded within the last 24 hours. States such as Delhi, Uttar Pradesh, West Bengal, Gujarat, and especially Kerala, have experienced a steady rise in cases. In the week of April 27th to May 3rd, 2025, nearly 6,000 individuals in Taiwan called for medical assistance at hospitals due to Covid-19-related symptoms. This marks a 78% increase from the previous week, representing a rise in case numbers for the fourth consecutive week.

In the US in early June 2025, more than dozens of NB.1.8.1 subvariants were identified in Washington. The variant was first detected in the US between late March and early April through daily screenings of international travelers at airports in California, Washington, Virginia and New York. Subsequent cases have been reported in Ohio, Rhode Island and Hawaii. In the US, around 300 deaths have been in place per week since Covid-19 in 2025-May. A regular summer surge is expected, consistent with seasonal patterns observed over the past few years.

GVN supports the following COVID-19 vaccine recommendations:

• Adults over the age of 65 and individuals with underlying conditions must receive the latest Covid-19 booster tailored to the circulation variant.
• All individuals over six months, including children and adolescents, are encouraged to stay up to date with vaccinations, especially before the fall and winter breathing seasons.
• Children between the ages of 6 months and 17 must receive an updated Covid-19 vaccine dose for their age if they have not yet been in the past year. Pediatric vaccinations can help prevent severe outcomes, including hospitalization and pediatric multisystem inflammatory syndrome (MIS-C).
• Pregnant individuals are highly encouraged to stay up to date with Covid-19 vaccinations. Vaccination during pregnancy reduces the risk of COVID-19 hospitalization in infants by 61% and protects newborns up to six months after birth. This is a particularly important window given the high rates of emergency department visits for infants for COVID-19. Studies have consistently shown that infection during pregnancy increases the risk of preterm birth, miscarriage, fetal death, and long-term neurodevelopmental problems. No safety concerns have been identified regarding vaccination in pregnancy or neonatal outcomes.
• Those who have not received a Covid-19 booster in the past year should consult their healthcare provider about the timing and eligibility of their updated vaccine.
• Co-administering Covid-19 and the influenza vaccine is recommended if necessary.
• Side effects from both Covid-19 and the flu vaccine are rare, and the cost-effectiveness of vaccinations prefers vaccination.
• The main advantage of vaccination is that it prevents severe illness rather than preventing the infection itself.

The rapid global adoption of NB.1.8.1 highlights the continued need for active surveillance, timely data sharing, and pandemic preparation. New variants are expected to emerge, and do not represent a public health emergency. Instead, it is a call for action for scientific vigilance and proactive health measures.

GVN repeats that this is not a reason for panic, but an opportunity to prepare. Investing in scientific collaboration, accurate public communication, and ongoing prevention tools remains important in navigating the evolving Covid-19 landscape.