Covid-19 cases increase, which sub-variant of Omicron is dominant in the community in our country?

Subtype BA.2 is still the main cause of Covid-19 infections.

According to the Department of Preventive Medicine, Ministry of Health, through monitoring in the recent past, the Covid-19 epidemic trend nationwide has generally decreased, recently it has slowed down to about 600 - 700 cases per day; the number of severe cases and deaths continues to decrease. In the past 30 days, the death/infection rate was 0.02%, in which the number of cases decreased 4.5 times and the number of deaths decreased 10 times compared to the previous month, there were 24 days when the whole country recorded no deaths.

However, in the past few days, the number of Covid-19 cases in our country has fluctuated and increased, especially on July 13, it exceeded 1,000 cases. This is the highest number in the past 40 days. NumberCovid-19 patientsThe number of severe cases requiring oxygen in our country has also fluctuated continuously, about 20 - 30 cases in recent days.

Vietnam has recorded Covid-19 cases infected with the BA.4 and BA.5 sub-variants of the Omicron strain in the community. These are all variants that spread quickly and have the ability to "evade" immunity.

Notably, Vietnam has recorded Covid-19 cases infected with the BA.4 and BA.5 sub-variants of the Omicron strain in the community. These are all fast-spreading variants and have the ability to "evade" immunity. This means that people who have contracted the BA.1 and BA.2 sub-variants can still contract BA.4 and BA.5 again.

Specifically, on June 15, 2022, through the infectious disease surveillance system at Bach Mai Hospital, 03 cases of infection with the BA.5 sub-variant were detected. According to initial investigation information from the National Institute of Hygiene and Epidemiology, Bach Mai Hospital determined that these 3 cases were recorded in the community, were Vietnamese people in the same family, came to Bach Mai Hospital for a health check on May 26, 2022 and had samples taken for testing.

In Ho Chi Minh City, through surveillance, 3 cases of infection with BA.4 and BA.5 variants were also detected in the community.

Covid-19 cases infected with BA.5 sub-variant in the community may increase, must drastically speed up vaccination of 3rd and 4th doses

Regarding the BA.5 sub-variant, the information from the Department of Preventive Medicine said that this variant was first recorded in South Africa in January 2022 and quickly spread to many countries around the world. This sub-variant contains a number of mutations (L452R, F486V and R493Q compared to the BA.2 sub-variant. Preliminary studies show that there are significant changes in antigenic properties compared to the two widely spreading BA.1 and BA.2 variants.

This sub-variant is 12% more transmissible than the BA.2 sub-variant (the most common sub-variant in Vietnam today). To date, there is no evidence that the BA.5 sub-variant is more virulent or causes more severe illness than previous older variants.

Around the world, many countries have detected the BA.5 sub-variant such as: Germany, Belgium, France, Austria, Italy, Portugal, Denmark, Norway, Spain, Switzerland, UK, USA, Canada, Australia, Israel, Pakistan, Singapore, Indonesia, Philippines, Thailand, Brunei... In South Africa, the incidence of this sub-variant has increased from less than 1% in January 2022 to 20% by the end of April. To date, South Africa is the country with the highest rate of infection of this sub-variant.

Implementing the plan of the People's Committee of Nghe An province, 21 districts and cities in the province simultaneously vaccinated children from 5 to 11 years old against Covid-19. Photo courtesy of Thanh Chung

Currently, the World Health Organization (WHO) has put the BA.5 sub-variant on the monitoring list. The European Center for Disease Prevention and Control (ECDC) has initially assessed that the BA.5 sub-variant of Omicron has been recorded in many European countries and has increased in some countries in recent weeks, recommending that countries maintain response measures such as booster vaccination, reminders for groups at risk of the disease, and strengthening key surveillance systems.

Worldwide, the BA.5 sub-variant ofOmicronhas been recorded in many countries and is likely to continue to penetrate into Vietnam; at the same time, our country has also recorded cases of infection with the BA.5 sub-variant in the community, so in the coming time, more cases of infection with the BA.5 sub-variant may be recorded in the community in our country. Thus, the number of cases may increase in the coming time due to the appearance of the BA.5 sub-variant.

The rate of increase in daily Covid-19 cases depends on many different factors such as the nature of the variant in terms of infectiousness (SARS-CoV2 virus is constantly changing and unstable); the ability of immune protection (acquired or due to vaccination) to decrease over time and vaccine coverage; from infection; response capacity and prevention and control measures of Vietnam.

Therefore, it is difficult to predict the specific increase in the coming time. However, according to data reported from European countries and South Africa, when the BA.5 sub-variant appeared, the spread rate was fast with the daily increase rate of the BA.5 sub-variant about 12-13% compared to the BA.2 variant and will gradually replace the BA.2 sub-variant.

Therefore, the disease prevention and control monitoring and response system from the central to local levels needs to continue to implement disease prevention and control measures, increase vaccination, remind groups at risk of the disease and continue to communicate so that people are always aware of disease prevention and control.