NB.1.8.1 variant accounts for 83% of COVID-19 samples in Ho Chi Minh City

The city's Department of Health on Saturday released gene sequencing results from COVID-19 patients who were clinically diagnosed and admitted to hospitals during the third week of May.

According to the report, 83 percent of the samples were identified as the NB.1.8.1 variant.

No evidence of faster transmission or increased severity

NB.1.8.1 is a subvariant of XDV.1, which itself originated from the XDV variant formed through genetic recombination between the JN.1 and XDE variants.

The first gene sequence of NB.1.8.1 was published in early 2025, according to gene databases.

The variant has been detected in 22 countries so far. However, no scientific studies have confirmed that it spreads more rapidly or leads to more serious illness than other strains.

The NB.1.8.1 has not been classified by the World Health Organization under any of the three COVID-19 variant risk groups: VUM (variant under monitoring), VOI (variant of interest), or VOC (variant of concern).

Taiwanese sources report that the NB.1.8.1 is currently the dominant variant there, with most severe cases occurring among individuals who have not received a full course of COVID-19 vaccination.

The U.S. Centers for Disease Control and Prevention also recently noted that the variant has been detected in numerous international travelers arriving at major airports in the United States.

NB.1.8.1 likely behind local rise in cases

In Ho Chi Minh City, surveillance data shows a rise in COVID-19 cases from week 16 to week 20 of 2025, spanning April 14 to May 18.

During this period, the city recorded an average of 11 cases per week – a significant increase compared to the first 15 weeks of the year, when only one or two cases were reported weekly.

In week 20 alone (May 12-18), the city confirmed 26 cases, 16 more than the weekly average of the previous four weeks.

Since the beginning of 2025, Ho Chi Minh City has recorded a total of 79 COVID-19 cases, including 43 inpatients and 36 outpatients.

No fatalities or severe cases requiring respiratory support have been reported.

Experts believe the emergence of the NB.1.8.1 variant may be contributing to the recent uptick in cases, similar to patterns observed in other countries.

They note that such increases are common when new variants appear.

Health authorities urge vigilance, not panic

On May 21, the Department of Health issued an official directive urging all healthcare units across the city to stay prepared for any potential outbreak resurgence and to maintain sufficient capacity for patient intake, emergency care, and treatment.

Health officials emphasized the need to detect and manage severe cases promptly to minimize the risk of death.

The department advises residents to stay calm but not complacent, given the unpredictable nature of COVID-19 globally.

People are encouraged to follow Ministry of Health recommendations, such as wearing masks in public and on public transportation, limiting unnecessary gatherings, washing hands frequently with soap or disinfectant, staying physically active, maintaining a healthy diet, and seeking medical attention promptly if symptoms like fever, cough, or shortness of breath develop.

Travelers to and from countries with high COVID-19 case numbers are advised to closely monitor their health to help protect themselves, their families, and close contacts.