Delta plus AY.4.2 variant and the level of risk of COVID disease spread

This is a disease that affects the respiratory system with symptoms ranging from mild to severe such as the common cold, fatigue, pneumonia, severe respiratory failure, affecting the digestive tract or other parts of the body, causing the patient to decease.

Corona virus variant is a "term" to describe a variant of a Corona virus that is significantly different from its fellow viruses. This difference is expressed in the following aspects: contagiousness (ability to transmit disease), virulence (ability to cause disease), sensitivity to treatment drugs/preventive vaccines (tolerance ability) of SARS-CoV-2 virus.

We can understand that changes in the nature of the genome are called "variants". After transforming, they will have clear and specific manifestations called "mutant".

Viruses only fully replicate in living cells of their host (bacteria, plants, or animals). The structure of the virus includes an outer shell of protein or sometimes lipids (alcohol and antibacterial soap are used to remove this shell), a core of RNA or DNA and sometimes the enzymes necessary for the first step. virus replication. During the replication process, the virus genome will change, especially viruses with RNA genomes. The SARS-CoV-2 virus has an RNA genome and it also has changes due to mistakes in the replication process. Most changes are meaningless when they do not change the genetic code of the virus, but at least one genetic code change is enough to qualify as a variant. Explaining the reason why the SARS-CoV-2 virus spreads so quickly, epidemiologists say that there are spike proteins on the surface that help the virus stick to the respiratory tract. After attaching, it will jump to epithelial cells and replicate, then escape from old cells to enter new cells and spread to the community through the nose and mouth. If genetic changes make these spike protein "tentacles" suck more tightly, it will inevitably lead to faster infection.

In mid-October 2021, the British Health Security Agency issued a report saying: "A new Delta variant recorded as AY.4.2 (also known as Delta plus) is spreading in the UK and is being monitored. This variant, includes mutations to the spike protein (A222V and Y145H) that the coronavirus uses to enter human cells.”

WHAT IS THE DELTA PLUS VARIANT AY.4.2?

Considered a close relative of the Delta variant, Delta plus (or AY.4.2.) was identified by British scientists last month. However, because this variant has not yet caused a state of emergency, it has not yet been officially named after a letter in the Greek alphabet, like other previous variants.

Francois Balloux, director of the Institute of Genetics at University College London (UK), said that the Delta plus variant has two mutations in the spike protein, helping the SARS-CoV-2 virus penetrate human cells.

"Delta remains by far the most dominant variant in terms of global transmissibility," said Maria Van Kerkhove, the World Health Organization's (WHO) technical lead on COVID-19. The Delta variant is continuing to mutate and the more widespread it is, the higher the risk of mutations. The United Nations health agency is currently monitoring 20 mutations of the Delta variant, of which AY.4.2 is one. may be of concern and are closely monitoring it."

DISEASE RISK LEVEL OF DELTA PLUS AY.4.2

Scientists are monitoring this Delta plus variant to see if it is more infectious or dangerous than previous variants. In a recent report, British experts said this variant accounts for 6% of all detected COVID-19 cases.

The UK is currently seeing a sustained and worrying rise in COVID-19 cases, reporting between 40,000 and 50,000 new infections per day in the last week, leaving experts to question why. He is now susceptible to COVID-19 infection. The report comes as cases and deaths are rising again in England, which lifted most epidemic prevention measures over the summer, including rules on masks and vaccine.

The Delta plus variant is reported to be 10-15% more infectious than the current Delta variant, but it is too early to say with certainty that it is the main cause of the increase in new infections in Older brother.

In the US, the Delta variant accounts for almost all COVID-19 cases, and the Delta plus variant is also occasionally detected but has not caused worrying consequences.

Like the US, Israel said it had confirmed a case of the Delta plus variant in an 11-year-old boy entering the country at Ben Gurion airport. This week, Russia also said it had recorded several quarantined cases of the Delta plus variant. Meanwhile, the Public Health Agency of Canada also confirmed that the Delta plus variant is present in Canada with 9 cases identified since July 2021.

It is worth noting that although Delta plus is being monitored, it is not yet considered a "variant under investigation" or a "variant of particular concern" by WHO, meaning that this variant has not been identified. It is determined that there are dangerous genetic changes related to the ability to infect, the severity of the disease, the ability to evade the immune system and difficulty in diagnosis and treatment. However, this situation may change if the Delta plus variant continues to cause a sharp increase in the number of COVID-19 cases.

Identifying a more transmissible variant is important because it could cause more COVID-19 cases in unvaccinated people.

According to statistical data, many regions of the world are still not fully vaccinated (only 2.8% of people in low-income countries have been vaccinated with at least one dose of COVID-19 vaccine) while other countries increasingly detecting cases of "breakthrough infection" when immunity to COVID-19 wanes around 6 months after full vaccination. In addition, a new variant can also cause the effectiveness of COVID-19 vaccines to decline.

The fight against SARS-CoV-2 with constantly emerging variants has been and will be a difficult battle for scientists in particular and humanity in general.

Editor: Ngoc Anh - Phacogen Institute of Technology;

(Master of Experimental Biology. University of Natural Sciences - Hanoi National University)

Referral:

Electronic information portal of the Ministry of Health

Saathvik R Kannan , Austin N Spratt , Alisha R Cohen , S Hasan Naqvi , Hitendra S Chand , Thomas P Quinn, Christian L Lorson , Siddappa N Byrareddy , Kamal Singh. Evolutionary analysis of the Delta and Delta Plus variants of the SARS-CoV-2 viruses. Journal of Autoimmunity, 2021. DOI: 10.1016/j.jaut.2021.102715