A highly contagious, "triple mutant" variant of SARS-CoV-2 has been spreading rapidly throughout India, causing concern for scientists around the world as nations begin to ease lockdown. Now, the World Health Organisation (WHO) has classified it as a variant of concern (VOC) as evidence begins to suggest it is more transmissible and possibly less vulnerable to the mRNA vaccines than other variants.
"We are classifying this as a variant of concern at a global level," Maria Van Kerkhove, WHO technical lead on COVID-19, told during a briefing.
"There is some available information to suggest increased transmissibility."
The variant belongs to a specific lineage, called B.1.617, that was first identified in India on October 5, 2020. Since then, it has been detected in the US, UK, and Singapore, amongst other nations, and has picked up attention owing to a variety of clinically relevant mutations of concern. Dubbed the "triple mutant", B.1.617 actually has multiple mutations (ranging from 13-17 currently identified) that has led to scientists complaining about the media-given name, but three of these are believed to directly impact how dangerous the virus may be.
In a report released on Tuesday, the WHO outlines the reasoning behind their latest classification of B.1.617 as a VOC. There are currently three sublineages of this variant – appropriately named B.1.617.1, B.1.617.2, and B.1.617.3 – which have varying amounts of spike mutations. There is limited evidence on just how problematic the variant is, with little peer-reviewed information available. Preliminary studies have identified a significant reduction in the neutralization of virus by antibodies from both the Pfizer-BioNTech and Moderna vaccines, suggesting these could be less effective, although it is uncertain whether they are still good enough to protect against the virus. However, statements by official regulators indicate that the vaccine will still be effective against this variant
“Potential impacts of B.1.617 lineage on effectiveness of vaccines or therapeutics, or reinfection risks, remain uncertain. Preliminary laboratory studies awaiting peer review suggest a limited reduction in neutralisation by antibodies; however, real-world impacts may be limited.” states the WHO report.
Despite the spreading cases of the variant, with 520 confirmed B.1.617 cases in the UK, more robust studies will be required before decisions are made. It now joins both P.1 from Brazil and B.1.351 from South Africa (among at least 8 other variants) that the WHO is actively monitoring. Increased epidemiological characteristics, such as how fast it can transmit, how severe the cases are, and how common re-infections occur, are all closely scrutinized to determine how dangerous these variants can be.
