Ruminations: COVID-19 Subvariants

"Recombinant variants are not an unusual occurrence, particularly when there are several variants in circulation, and several have been identified over the course of the pandemic to date."
"As with other kinds of variant, most will die off relatively quickly."
Susan Hopkins, chief medical adviser, U.K. Health Security Agency (UKHSA)

"Scientists are looking for signs that Omicron recombinants such as XE change disease severity, transmissibility or impact the effectiveness of diagnostic tests, vaccines or treatments for COVID-19."
"While preliminary international reports have shown that XE has modestly increased transmissibility compared to BA.2, more data is needed to confirm this finding."
Public Health Agency of Canada

Tulio de Oliveira posed for a portrait in his lab

Tulio de Oliveira’s team at Stellenbosch University in South Africa discovered the BA.4 and BA.5 subvariants of Omicron. Credit: Stefan Els/Stellenbosch University

The Omicron subvariant XE -- one of several hybrid variants that have recently emerged -- is being tracked by Health Canada. That they are considered recombinant variants indicates that they contain genetic material of two or more different variants or subvariants. To the present, 32 detections of Omicron recombinants are in circulation. An April 8 technical briefing from the U.K. Health Security Agency identifies XE with three mutations, not present in BA.1 or BA.2.

The "stealth Omicron", the XE variant has been identified as a recombination of Omicron BA.1 and Omicron BA.2, the highly-transmissible Omicron driving Canada's sixth wave at the present time. The U.K. identified its first case of XE in January of 2022. To April 4, 1,179 XE cases have been confirmed in the United Kingdom, and since reported found in other countries, including Canada, India, Japan, Thailand and Israel. Obviously carried from a source location through travel and return to one's home country.

Viruses like HIV and influenza commonly produce recombinant variants. a not-unique phenomenon among such pathogens. Yet other recombinants have been identified; variants XD and XF, both labelled Deltacron; combining Delta and Omicron variants. Delta, seen to be more dangerous and communicable than the original from which it developed from through mutation, and Omicron variants, less lethal, but more communicable.

Most confirmed cases of XD, identified by the UKHSA, have been found in France, and the second most numerous findings at this eaqrly stage, in the United Kingdom. XF is just behind XD in prevalence, but appears to have petered out. The World Health Organization's technical lead, Maria Van Kerkhove, stated based on initial analysis XE has a ten percent growth advantage over BA.2, making it slightly more transmissible.

Symptoms that arise with contracting any of the recombinant variants are unlikely to be more serious than other variants, since reports indicate BA.2 is no more severe than BA.1 and variants of the original COVID-29 tended to result in decreased severity. XE under Omicron is considered a variant of concern by the World Health Organization; with XD listed as a monitored variant.

The most reliable way to being protected from experiencing severe COVID symptoms according to health experts -- irrespective of the variant type -- is through a full series of vaccinations and a booster dose. "We need to critically ensure that those around the world, particularly those who are most vulnerable, get vaccinated in every single country", stated Van Kerkhove of the WHO.

Physical distancing, mask wearing, avoiding crowded indoor spaces, better ventilation (opening windows and doors) and remaining home if unwell, continue to be advised as measure that work well in preventing the spread of the virus, as well as the prevention of severe disease outcomes and death. It is primarily among the large numbers of people in emerging economies that have not been vaccinated from among whom the variants have the opportunity to mutate and to thrive.