The highly contagious delta coronavirus variant is also spreading in countries with high levels of vaccination coverage. The variant harbors more than a dozen mutations that also lead to vaccine escape. So-called “vaccine escape” occurs when the virus changes so that it evades the full effect of the vaccine and spreads faster from person to person.
The virus strain B.1.617.2, which was first identified in India, spreads around twice as fast as the previously predominant alpha variant. Alpha was already around 50 percent more contagious than the original Covid-19 wild type. Delta was first described in the Indian state of Maharashtra in October 2020 and has since spread rapidly across the world.
The Federal Office of Public Health (BAG) writes on its Covid-19 website that the Delta virus variant has been “worrying since the beginning of May 2021, as there is an increased risk of infection, an increased risk of re-infection and a reduced effectiveness of Covid-19- “Vaccination is suspected”. According to BAG data, Delta has increased by 28.4 percent in the last 7-day average. In their latest report, the researchers from the federal Covid-19 task force also write that the delta variant could trigger another corona wave with superspreader events.
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“Delta is fitter and faster”
“It seems that the Delta variant is fitter and faster because it has acquired several mutations that seem to give it the ability to outsmart our immune system and give it an advantage over other strains of the virus.” This explained the US epidemiologist Ravina Kullar, an infectious disease specialist at the David Geffen School of Medicine in Los Angeles.
It is quite normal for a circulating coronavirus to mutate. Delta has several mutations that make the virus more effective. The exact functions of the delta mutations have still not been clearly researched scientifically. All that is known is that the mutations allow the virus to attach to human cells more easily and avoid some immune reactions.
In addition to Delta, there is also the Delta Plus version with the abbreviation AY.1. This variant, which has not been widely used up to now, is considered to be even more transferable and more resistant to vaccines that have previously been approved, such as Deepti Gurdasani executes, clinical epidemiologist at Queen Mary University of London. Gurdasani assumes a three-fold probability of transmission of Delta compared to the original virus strain.
High vaccination protection against Delta
According to one in the journal “The Lancet” According to a published study based on UK patient data, Delta suggests a more severe rather than a lighter course of the disease. The risk of hospitalization after a delta infection is about twice as high as after an infection with the alpha variant.
While the risk of infection seems comparatively high, the risk of death in Great Britain so far has been rather low. It is assumed that this is related to the high level of vaccination among the population – and not to the fact that the disease progression caused by Delta is fundamentally easier. But even with people who have been vaccinated twice, it can lead to severe courses and even death, as new figures from Great Britain show. So far, 117 deaths have been registered after a Delta infection. 50 of the dead were fully vaccinated.
Delta now causes more than 90 percent of all new infections in the UK. In spite of all this, the vaccination remains the best antidote against corona. According to an Israeli study, the mRNA vaccine from Pfizer / Biontech used in Switzerland is 60-80 percent effective against the Delta variant. At the beginning of the year, vaccination protection against the alpha variant prevailing at the time was around 93 percent, according to Pfizer / Biontech data. (kes)