What is the new variant XE of COVID-19?
The Omicron variant of SARS-COV-2 which is responsible for over 90% of all positive cases worldwide has three known sub-lineages: BA.1, BA.2, and BA.3. The BA.1 subvariant was the most prevalent during the initial Omicron wave around the end of 2021. However, the newer BA.2 subvariant has become dominant during the third wave due to its superior transmissibility, accounting for almost 94 per cent of all Omicron infections in March 2022.
The XE subvariant of SARS-CoV-2 is essentially a recombinant mutant of Omicron, combining mutations found in the BA.1 and BA.2 subvariants. Since its discovery in the United Kingdom in mid-January, more than 600 samples of the XE subvariant have been detected in the UK so far, along with several in China and Thailand.
What Is a Recombinant Virus?
Recombinant viruses emerge when a person is infected with two or more variants at the same time which allows these variants to mix some of their genetic material. Consequently, a novel hybrid virus is created in the body of the infected person. This novel hybrid virus usually combines several characteristics of each parent subvariant. Recombinant variants are not unusual, especially if various variants are simultaneously circulating. Throughout the pandemic, several recombinant variants have emerged and circulated. In fact, according to a recent study that has yet been peer-reviewed, recombinant variants may be responsible for as much as 5% of the COVID-19 cases circulating in the U.S. and U.K. Several experts also note that much like other types of variants, recombinant variants are likely to die off relatively rapidly.
What is the logic behind the name “XE”?
Scientists have designated the recombinant lineage of SARS-CoV-2 the virus responsible for COVID-19 with prefixes that start with the letter “X”. Therefore, when a new recombinant variant is discovered, scientists name them by using the prefix “X” and following it by a letter according to the order of its discovery. The reason that this recombinant subvariant of SARS-CoV-2 has been named the XE recombinant subvariant is that while none of them has caused major concern, XA, XB, XC, and XD recombinant subvariants have already been discovered. In fact, more recently, several minor strains of the X lineage such as XG, XH, XJ, XK, and XL has also been discovered.
How concerned should we be about COVID-19 XE variant?
Recombination is an expected and somewhat prevalent mutational event in most viruses including coronaviruses especially when there are several variants circulating simultaneously. However, not every mutation has significant consequences for the viral transmissibility, symptom severity, or vaccine effectiveness.
Experts argue that it might be too soon to draw conclusions regarding the ability of the XE subvariant of SARS-CoV-2 to infect others, cause severe disease or evade protection provided by our current vaccines. Moreover, as this new subvariant has so far displayed a variable growth rate, there is not sufficient data to determine if the new subvariant has a significant growth advantage. Still, earliest estimates from the UK Health Security Agency (UKHSA) and the World Health Organization (WHO) suggest that the XE subvariant might be around 10% more transmissible than the dominant Omicron BA.2 subvariant.
What are the symptoms caused by the COVID-19 Omicron XE subvariant?
So far, the XE subvariant has not been found to cause significantly different or more severe disease compared to other Omicron subvariants. The XE subvariant has not yet been associated with any unique symptoms. It seems to share all the symptoms of the other Omicron subvariants of SARS-CoV-2, which are typically not very severe. Some sources note that an infection with the Omicron XE subvariant may start with symptoms such as fatigue and dizziness, which may be followed by headaches, sore throat, and fever. Symptoms such as loss of smell and taste have not been yet reported. Other common symptoms include nausea, vomiting, and diarrhea. As such, none of these symptoms are unique to this subvariant or more severe than other Omicron variants. Therefore, although its discovery has led to major concern regarding the possibility of a novel wave of COVID-19, the XE variant is not being considered significantly different from Omicron at least unless future data demonstrates significant differences in viral transmission, disease characteristics and symptom severity.
Will the vaccines work against COVID-19 XE variant?
Although research on the exact viral characteristics of the Omicron XE subvariant of SARS-CoV-2 is inconclusive, experts agree that as the Omicron XE subvariant is essentially a hybrid of the BA.1 and BA.2 subvariants, the impact of our current vaccines in reducing the severity of symptoms, along with rates of transmission, hospitalization, and mortality is highly likely to hold for the Omicron XE subvariant. Altogether, unless upcoming data proves otherwise, our current vaccines and treatments are presumed to provide similar levels of protection against the Omicron XE subvariant as they do against other Omicron subvariants. Thus, as with other variants of Omicron and SARS-CoV-2 in general, vaccination and booster shots may not prevent getting infected altogether. However, vaccination remains extremely efficient in preventing severe disease, hospitalization, and death.
What are the precautions against COVID-19 XE variant?
The precautions recommended for other Omicron subvariants of SARS-CoV-2 remain applicable to the Omicron XE variant. Experts point particularly to the importance of vaccination. As XE is a hybrid of two Omicron subvariants (BA.1 and BA.2), vaccines are very likely to offer similar levels of protection against developing severe disease from this variant of SARS-CoV-2. Indeed, thus far, no evidence has been found to suggest that our current vaccines are less effective against the Omicron XE variant and health experts agree that getting fully vaccinated still constitutes the most efficient strategy against the virus. Fully vaccinated individuals are known to have higher immunity against all the Omicron variants. Even if they get infected, those who are fully vaccinated develop significantly milder symptoms. Especially for the protection of groups that are more vulnerable to developing severe symptoms including older people, immunocompromised people, and those with health conditions such as cancer, diabetes, obesity, cardiovascular disease, and chronic respiratory disease, vaccination remains vital. Thus, together with attention to other measures such as testing, physical distancing, and wearing masks, by getting fully vaccinated and receiving booster shots, if possible, we can protect ourselves against getting sick with and spreading the virus regardless of the variant.
Will the COVID-19 Rapid Antigen Test Kits work against the XE variant?
The subvariant XE can be imagined as a sum of BA.1 strain and BA.2 strain. The nucleocapsid protein mutations of this SARS-CoV-2 variant carried by the XE subvariant has inherited from the BA.2 strain which our RapidFor™ SARS-CoV-2 Rapid Antigen Test Kit already recognizes by pairing the selected monoclonal antibody. In the light of our academic knowledge, we can safely say that the RapidFor™ SARS-CoV-2 Rapid Antigen Test Kit can work against the XE variant.
