The continued spread of the COVID-19 virus has created variations in the Greek alphabet – a naming system used by the World Health Organization (WHO) to track new mutations in the virus. virus that causes SARS-CoV-2. Some have equipped the virus with better ways to infect people or evade the protection of vaccines.
Scientists remain focused on Delta, currently the dominant variant worldwide, but are keeping an eye on others to see what might one day happen.
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Delta – still dominant
The Delta variant discovered for the first time in India remains the most worrisome. It is striking unvaccinated populations in many countries and has been shown to infect a higher proportion of vaccinated people than previously vaccinated individuals.
WHO classifies Delta as a variant of concern, which means it has been shown to increase transmission, make disease worse, or reduce the benefits of vaccines and treatments.
According to Shane Crotty, a virologist at La Jolla Institute of Immunology in San Diego, Delta’s “superpower” is its transmissibility. Chinese researchers found that people infected with Delta carried 1,260 times more virus in their noses than the original version of the coronavirus. Several US studies suggest that viral loads in vaccinated individuals with Delta infection are on par with those in unvaccinated individuals, but more research is needed.
While the original coronavirus takes up to seven days to cause symptoms, Delta can cause symptoms two to three days faster, giving the immune system less time to react and strengthen its defenses. .
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Lambda – coming to an end
The Lambda variant has attracted attention as a new potential threat, but this version of the coronavirus, first identified in Peru in December, appears to be regressing.
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According to data from GISAID, a database that tracks SARS-CoV-2 variants, although Lambda-related cases have increased in July, reports of this variant have decreased globally. in the past four weeks.
WHO classifies Lambda as a variant of interest, which means it carries mutations that are suspected to cause a change in transmissibility or cause more severe disease, but it is still under investigation. Laboratory studies have shown it to have resistance mutations to vaccine-induced antibodies.
WHO says it’s looking at Mu, a new COVID-19 variant of interest
Mu – one to see
Mu, variant formerly known as B.1.621, was first identified in Colombia in January. On August 30, WHO designated it a variant of interest due to several associated mutations and assigned a Greek letter name to it.
Mu carries key mutations, including E484K, N501Y and D614G, which have been associated with increased transmissibility and decreased immune defense.
According to the WHO Bulletin published last week, Mu has caused some of the larger outbreaks in South America and Europe. While the number of genetic sequences identified as Mu has fallen below 0.1% globally, Mu represents 39% of the variants sequenced in Colombia and 13% in Ecuador, where Its prevalence is “continuously increasing,” the WHO reports.
The global health agency said it continues to monitor Mu for changes in South America, particularly in areas where it is co-circulating with the Delta variant. Maria van Kerkhove, head of WHO’s emerging diseases unit, said the circulation of this variant is decreasing globally but needs to be closely monitored. During a press conference last week, White House medical adviser Dr Anthony Fauci said US officials are monitoring it, but so far Mu is not considered an immediate threat.
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More on the go?
Getting more people immunized against COVID-19 is important because large groups of unvaccinated people give the virus an opportunity to spread and mutate into new variants.
Experts say that effort must be stepped up internationally to keep variants from emerging and unchecked in communities of poor countries, where very few people are vaccinated.
Even so, while current vaccines prevent serious illness and death, they do not prevent infection. The virus is still capable of replicating in the nose, even in vaccinated people, who can then transmit the disease through tiny aerosol droplets.
According to Dr. Gregory Poland, a vaccine developer at the Mayo Clinic, defeating SARS-CoV-2 will require a new generation of vaccines capable of stopping transmission. Until then, Poland and other experts say, the world remains vulnerable to the rise of novel coronavirus variants.