12 July 2024

In the two years since it was declared a pandemic, the COVID-19 virus has given birth to many variants and, recently, to recombinants as well. People, therefore, need to stay updated about the changing virus to maximize their protection against the widespread and potentially fatal disease it causes.

What is a recombinant?

A recombinant is born when one person becomes infected with two variants or subvariants, which then interact inside their body. These hybrid forms of the virus are given the prefix “X”.

The list of hybrids is getting longer, as countries around the world decode genome sequences of their local cases and report the results to GISAID. Established in 2008, this global initiative provides open access to the genomic data of the influenza virus and the coronavirus responsible for the COVID-19 pandemic.

Scientists believe more than a dozen COVID recombinants may be circulating.

“You may have already heard of XE, XG, XH, and XJ. In all, there is talk of about 17 recombinants already regarding COVID-19,” Medical Sciences Department director-general Dr. Supakit Sirilak said recently. “But officially, only three recombinants have been recognized. They are XA, XB, and XC. The rest are still undergoing the verification process.”

How worried should we be?

Supakit said people in Thailand do not need to worry about a hybrid, at least for now. His department has so far detected just one possible recombinant in Thailand – a suspected case of XJ, the hybrid first detected in Finland. It was found during the department’s weekly genome sequencing of 500-600 randomly sampled cases. The suspected case – a fully vaccinated 34-year-old who was infected in February – has already made a complete recovery.

It should also be noted that, currently, nearly 100 percent of all COVID-19 infections in Thailand are caused by Omicron.

However, the Centre for Medical Genomics at Mahidol University’s Faculty of Medicine, Ramathibodi Hospital reported early this month that it had detected one case of XE.

฿211 million approved for study of Thailand’s first plant-based COVID vaccine

What are the risks?

The World Health Organisation (WHO) has warned that recombinants must be closely monitored and studied to help people navigate the ongoing pandemic. Emerging recombinants may, after all, affect the severity of COVID-19 symptoms as well as the efficacy of vaccines.

Most recombinants have not been a cause for alarm, though.

XD, which is a combination of Delta AY.4 and Omicron BA.1, for example, has not shown to be any more transmissible than existing variants.

But some experts say XE – which is under study – deserves special attention because it is even more transmissible than Omicron BA.2, the subvariant currently wreaking havoc across the world. Data indicates Omicron BA.2 was responsible for 93.6 percent of the world’s new COVID-19 infections last week.

Eminent virologist Tom Peacock recently tweeted a UK update showing that XE was spreading 10-20 percent faster than BA.2.

The good news is that XE, which was first detected in the United Kingdom on January 19, appears to be a mild form of the virus.

Peacock says this is because recombinants act similarly to their parents, which in XE’s case are the milder-seeming Omicron BA.1 and BA.2 subvariants.

Thailand’s COVID-19 situation

As of Wednesday, Thailand ranked 10th in the world for COVID-19 infections over the previous seven days with more than 168,000 new cases. Meanwhile, the virus was responsible for 686 deaths over the past week. This is despite most Thais already being fully vaccinated.

Although COVID-19 infections in Thailand are on an upward trend, the government has not banned travel and celebrations during this week’s Songkran holiday. Instead, the Public Health Ministry has merely asked people to wear face masks outdoors, avoid crowds, and not splash water.

Authorities are meanwhile preparing to declare COVID-19 an endemic disease by July and to trigger the easing of restrictions.

However, that plan could be derailed if the infection and mortality rates rise again.

By Thai PBS World’s General Desk

COVID-19 Omicron BA.2 will supersede BA.1 in next two weeks in Thailand