It has been 18 months since COVID-19 began to grab the world’s attention, quickly spreading from the Chinese city of Wuhan before infecting and killing millions and overwhelming health systems in all corners of the globe. The global death toll is rapidly approaching 4 million, with 180 million people infected with the virus at some stage. During this time, the virus has spread and mutated multiple times. Several variants of the original COVID-19 virus are now more transmissible, with one predicted to be the world’s dominant variant soon.
What are the main variants?
Late last month, the World Health Organisation (WHO) renamed the different variants after letters of the Greek alphabet. In Australia, there are three variants of concern: Alpha, Kappa, and Delta. They are also sparking record-high infections in parts of Europe and the subcontinent, while variants known as Beta and Gamma are also wreaking havoc in Africa and South America.
The WHO is closely watching the Alpha, Beta, Gamma, and Delta variants, but Delta is the one of most concern. South Africa, but health experts say there have been very, very few cases of it in Australia. ” src=”https://sl.sbs.com.au/public/image/file/87f16c88-3676-4e64-ba71-f3328d650592″ alt=”Family members wearing full PPE suits carry the remains of their elderly family member who died of COVID-19 in Johannesburg, South Africa.” width=”700″ height=”467″ />
The Beta variant was first identified in South Africa, but health experts say there have been very, very few cases of it in Australia.
EPA
An RNA virus causes COVID-19, the same virus which causes influenza.
Professor Robert Booy, an infectious diseases specialist at the University of Sydney and the Immunisation Coalition, said RNA viruses mutate “very easily”.
“COVID-19, like influenza, doesn’t copy itself very well at all, so the progeny, the babies of one virus, can be slightly different, mutated from the original virus,” he told SBS News.
“Viruses want to survive just like you, and I want to survive, so although they don’t have volition, they can’t decide. The viruses that do survive are those that can transmit. So in mutating, those that can transmit from one person to another, and on and on, become entrenched in the community.”
Delta: the ‘dominant variant.’ It is behind the recent cluster of cases in Sydney and was seen during a recent outbreak in Melbourne. Firstt identified in India, Delta is now being reported in more than 80 countries and has health authorities increasingly worried due to how highly transmissible it is.
“The Delta variant is well on its way to becoming the dominant variant globally because of its increased transmissibility,” WHO’s chief scientist Soumya Swaminathan said last week.
Catherine Bennett, chair in epidemiology at Deakin University, said Delta “is pretty much everywhere where COVID is at the moment”. “It’s a variant that we’ve been watching because we have seen it outcompete the other variants of concern,” she said. “It can quickly outcompete the other variants that are there. We saw it in England, we’re seeing it across Europe now, and we’re also seeing it in the US. It’s quickly becoming established in some areas as the dominant strain.”
Just three months after being first detected in the UK, Delta makes up more than 99 percent of cases there. It also makes up 90 percent of new infections in Russia, where record-high daily cases are reported compared to the pandemic’s start.
“This particular variant is potentially 60 percent more infectious than we saw with the Alpha variant, and that already was 50 percent more infectious than other variants,” Professor Bennett said.
“Researchers found that with the Delta variant, the ‘viral load’ carried by those infected is higher than other variants,” Professor Bennett said. Research from Public Health England estimates Delta has a reproductive value of 6.0, compared to 2-3 from the other variants. That means for every one person infected with Delta, six other people will catch the virus.
“[It] builds quicker, and people can become infectious sooner, with people likely to be more virulent due to the high viral load. And while data suggests it is more transmissible, epidemiologists say it is too soon to know if it causes more severe illness. India is also monitoring a new variant, Delta Plus, with its health ministry reporting 22 cases.
India’s federal health secretary Rajesh Bhushan said the same variant had been found in eight other countries and is being closely watched. Still, the original Delta variant remains the most concerning.
