Genome sequencing for SARS-CoV-2 conducted by the hospital in collaboration with Oxford University Clinical Research Unit show the XBB sub-variant was detected in December 2022, however, it was still at a low rate.

The XBB was first identified in India in August and quickly become the dominant strain there, as well as in Singapore. It has since evolved into a family of subvariants, including XBB.1 and XBB.1.5.

According to details given by CNBC, scientists and public health officials have been closely monitoring the XBB subvariant family for months because the strains have many mutations that could render the COVID-19 vaccines, including the omicron boosters, less effective. Indeed, it is even possible that it could even lead to more breakthrough infections.

The joint research team of Ho Chi Minh City Hospital for Tropical Diseases and Oxford University Clinical Research Unit are now keeping a close watch on new infections, warning of the risk of infection, especially among those who have not been vaccinated or are yet to be fully vaccinated.

Therefore, booster vaccinations of the COVID-19 jab are very important, especially for those aged 50 years old and older, those aged 18 and older with moderate to severe immunodeficiency, and those 18 and older in a high-risk group for exposure to COVID-19, said scientists.