The HCM City Health Department in early January reported that the XBB variant was found in three out of 52 Covid-19 test samples in December 2022. The patients received medical treatment at the HCM City Hospital for Tropical Diseases. 

The dominant variant is still BA.2.75.

After that, the Ministry of Health’s (MOH) monitoring system recognized the appearance of XBB in Tay Ninh province.

XBB is believed to be the SARS-CoV-2 virus variant with the highest immune resistance so far. 

According to the US CDC (Centers for Disease Control and Prevention), more than 40 percent of Covid-19 cases in the US now are from XBB. In New England in the US, the proportion of XBB infections has increased from 11 percent to 75 percent.

As XBB is a new virus, scientists are still working to find out if it is different from other variants.

Dr Henry Redel, Chief of Infectious Diseases at Saint Peter's University Hospital, said on HuffPost that in general, viruses tend to become more transmissible and less serious, like XBB.

The most common symptoms of XBB are body aches and congestion.

Evidence shows that the symptoms of variants vary slightly from each other. Omicron, for example, causes cold-like symptoms (fatigue, runny nose, sneezing and muscle aches), while Delta and Alpha often cause loss of smell and taste.

Dr Julie Parsonnet, an expert in infectious diseases from Stanford Health Care, said XBB infections result in more pain, and have nose congestion and headache. Other symptoms are fever, chill, cough and sore throat. 

Meanwhile, Dr Thomas Campbell said that as XBB is part of Omicron, the loss of taste and smell will not be common.

Studies have all confirmed the benefits of vaccination, especially in reducing the severity of the infection and need for hospitalization, especially for people aged over 65 with underlying conditions.

According to the Department of Preventive Medicine, XBB has been detected in Tay Ninh province and HCM City, but the pandemic is controlled with a sharp fall in the number of infections and deaths. Vietnam is among the countries with the highest vaccination rates in the world. 

Linh Giao