Professor Yong Poovorawan has shared information from the journal Cell indicating that the current global COVID-19 outbreak is caused by variant G, which spreads easily due to a high viral load in the throat. However, this variant is not associated with increased severity of the disease. He is collaborating with the Disease Control Department to gather data in preparation for a potential second wave of outbreaks. 

 

       Professor Yong Poovorawan, head of the Clinical Virology Research Center at the Department of Pediatrics, Faculty of Medicine, Chulalongkorn University posted on Facebook referencing information published in the journal Cell that COVID-19 is spreading more easily.

       Originally, the strains of COVID-19 began in China as strain S and strain L, with strain L spreading more easily outside of China. The strain that initially spread in Thailand was strain S, characterized by a specific mutation at position 829 on the spike protein, which changed to Threonine (T829), leading to its designation as strain T.

       Strain T is a descendant of strain S and is now believed to be extinct, as it only occurred in Thailand. Strain L, when it spread outside the country, particularly in Europe, gave rise to descendants known as strains G and V. Strain G has a mutation at position 614 on the spike protein, changing from Aspartate (D) to Glycine (G), hence referred to as strain G614. This strain G spreads very easily and has further descendants known as strains GH and GR.

Variant G is Highly Contagious with High Viral Load in the Throat

       According to the journal Cell, past studies have shown that variant G spreads easily because individuals infected with strain G have a high viral load in their throats, making it easier to transmit to others. This results in a higher rate of spread compared to other variants, although variant G does not increase the severity of the disease; it merely facilitates its global spread.

        Therefore, the variant currently spreading widely around the world is predominantly variant G. Variants imported from abroad and detected in Thailand's State Quarantine have already mutated to variant G. It is believed that if a second wave occurs, the variant that will spread will likely be variant G returning from Western countries, and it is unlikely to be strain S, which previously circulated in Thailand.

Collecting Data to Prepare for a Second Wave of Outbreaks 

       Currently, the center is receiving excellent cooperation from the Urban Disease Control Institute in studying the variants present, particularly those in State Quarantine, to collect baseline data. If an outbreak occurs in Thailand, it will be possible to trace back to determine which country the variant likely originated from. If variant G spreads more easily than variant S, as previously studied, then the second wave must be fully prepared for.

However, the variants that have mutated are not related to the severity of the disease; they are monitored for epidemiological tracking and their ease or difficulty of transmission. Since variant G thrives well in the respiratory tract, it has a higher viral load.

 

Source: Facebook Yong Poovorawan