CHICAGO – The continued spread of the SARS-CoV-2 virus has spawned a Greek alphabet of variants, a naming system used by the World Health Organization (WHO) to track new mutations in the virus that causes COVID-19. Some have equipped the virus with better ways to infect humans or evade protection against vaccines.
Scientists are still focused on Delta, now the dominant variant around the world, but they are following others to see what their place may one day have.
Delta still dominant
The Delta variant first detected in India remains the most worrying. It draws the attention of unvaccinated populations in many countries and has been shown to be able to infect a higher proportion of vaccinated people than their predecessors.
The WHO classifies Delta as a variant of concern, that is, it has been shown to be able to increase transmissibility, cause more serious diseases, or reduce the benefit of vaccines and treatments.
According to Shane Crotty, a virologist at the La Jolla Institute of Immunology in San Diego, Delta’s “superpower” is its transmissibility. Chinese researchers found that people infected with Delta carry 1,260 times more noses in their noses compared to the original version of the coronavirus. Some research in the United States suggests that the viral load in vaccinated people who become infected with Delta is at the level of those who are not vaccinated, but more research is needed.
Although the original coronavirus took up to seven days to cause symptoms, Delta can cause symptoms two to three days faster, giving the immune system less time to respond and defend itself.
Lambda down
The Lambda variant had caught attention as a new threat, but this version of the coronavirus, first identified in Peru in December, appears to be receding.
Although Lambda-related cases increased in July, reports of this variant have fallen globally over the past four weeks, according to data from GISAID, a database that tracks SARS variants. CoV-2.
The WHO classifies Lambda as a variant of interest, that is, it carries mutations suspected of causing a change in transmissibility or causing more serious diseases, but it is still being investigated. Laboratory studies show that it has mutations that resist vaccine-induced antibodies.
Mu is one of the must see
Mu, the variant formerly known as B.1.621, was first identified in Colombia in January. On August 30, the WHO designated it as a variant of interest due to several related mutations, and assigned it a Greek letter name.
Mu has key mutations, including E484K, N501Y, and D614G, that have been linked to increased transmissibility and reduced immune protection.
According to the WHO Bulletin published last week, Mu has caused some of the largest outbreaks in South America and Europe. Although the number of genetic sequences identified as Mu has fallen below 0.1% worldwide, Mu represents 39% of the sequenced variants in Colombia and 13% in Ecuador, places where its prevalence “It has risen steadily,” the WHO said.
The world health agency said it continues to monitor Mu for changes in South America, especially in areas where it is circulating with the Delta variant. Maria van Kerkhove, head of the WHO’s emerging diseases unit, said the circulation of the variant is declining globally, but it needs to be watched closely. At a press conference last week, White House Chief Medical Officer Dr. Anthony Fauci said U.S. officials are watching him, but so far Mu is not considered an immediate threat.
Is there more along the way?
Getting more people vaccinated against COVID-19 is critical, as large groups of unvaccinated people give the virus more opportunities to spread and mutate into new variants.
This effort must be intensified internationally to prevent variants from appearing uncontrollably among the populations of poor nations where very few people have been inoculated, experts say.
However, while current vaccines prevent serious illness and death, they do not block infection. The virus can still replicate in the nose, even among vaccinated people, who can then transmit the disease through small aerosolized drops.
Defeating SARS-CoV-2 will likely require a new generation of vaccines that will also block transmission, according to Dr. Gregory Poland, a vaccine developer at the Mayo Clinic. Until then, say Poland and other experts, the world remains vulnerable to the rise of new variants of coronavirus.