Recent weeks have seen an increase in SARS-CoV-2 infections in Asian countries, with a rise in detections of the NB.1.8.1 variant. This variant has been classified as a variant under monitoring (VUM) by ECDC and WHO.

Background

Recent reports show a surge in SARS-CoV-2 infections in Asian nations since mid-February, especially in the Eastern Mediterranean, South-East Asian, and Western Pacific regions. Many of these cases are linked to the NB.1.8.1 variant, a new Omicron-descendant strain.

In contrast, EU/EEA countries have had limited SARS-CoV-2 circulation recently, without a winter epidemic. However, data from the European Respiratory Virus Surveillance Summary (ERVISS) indicates a recent increase in SARS-CoV-2 indicators, following winter epidemics of influenza and RSV.

• No significant rise in severe COVID-19 cases has been observed so far.
• Analysis suggests similar impacts on hospital admissions during COVID-19 epidemics and seasonal influenza outbreaks.

NB.1.8.1 Variant

NB.1.8.1, a descendant of Omicron variants, is causing increased SARS-CoV-2 infections in Asia. Factors contributing to its growth include waning population immunity and slight immune evasion advantages. However, there is no evidence of increased severity compared to other variants.

Laboratory studies indicate lower infectivity of NB.1.8.1 compared to XEC, a previous dominant Omicron variant. Vaccine effectiveness studies are ongoing, but early results suggest no significant impact on severe disease.

ECDC and WHO have classified NB.1.8.1 as a variant under monitoring, expecting its circulation to rise in the EU/EEA. Despite this, the variant is not deemed to pose additional public health risks.

Surveillance Gaps in the EU/EEA

Surveillance data gaps exist in the EU/EEA, particularly in primary care and severe disease monitoring. Recommendations for year-round surveillance of respiratory viruses aim to address these gaps and improve data accuracy.

Scenario Projections for Summer 2025

ECDC's scenario projections for COVID-19 dynamics in the EU/EEA predict a potential wave in summer 2025 due to waning population immunity. The model suggests a peak in hospital admissions similar to summer 2024, with variations across countries and scenarios.

Limitations exist in the model assumptions, including vaccine uptake and surveillance quality. The results are based on data from six countries and may not fully represent all EU/EEA nations.

Vaccination Coverage and Effectiveness

Information on vaccination coverage and effectiveness against NB.1.8.1 is still pending, with ongoing studies expected to provide more insights in the future.