The discovery of the so-called Delta Plus coronavirus variant, a new strain of the Delta variant first identified in India, demonstrates how quickly the coronavirus that causes COVID-19 can mutate and raises fears that vaccine-resistant strains of the disease could emerge in the near future, experts told Sputnik
MOSCOW (Pakistan Point News / Sputnik - 25th June, 2021) The discovery of the so-called Delta Plus coronavirus variant, a new strain of the Delta variant first identified in India, demonstrates how quickly the coronavirus that causes COVID-19 can mutate and raises fears that vaccine-resistant strains of the disease could emerge in the near future, experts told Sputnik.
The Delta COVID-19 strain is one of four defined by the World Health Organization (WHO) as a "variant of concern," along with the Alpha, Beta, and Gamma variants, which were first identified in the UK, South Africa, and Brazil, respectively.
Scientists first discovered the Delta variant in India in late 2020. Since then, this highly-transmissible COVID-19 strain has spread rapidly across the world, particularly in Europe, where it has become the dominant variant of the disease.
The European Centre for Disease Prevention and Control estimates that the Delta variant is 40% to 60% more transmissible than the Alpha variant of the disease, and more than 90% of new COVID-19 cases reported in England over recent weeks have been this strain of the virus.
The continued spread of the Delta variant across Europe prompted German Chancellor Angela Merkel to say on Thursday that the region was on "thin ice" and faced the prospect of another devastating wave of the disease this summer if people failed to remain vigilant.
More than half of the European Union's population has already received at least one COVID-19 vaccine shot, although data published by Public Health England suggests that one vaccine dose gives approximately 30% protection against the Delta variant.
The recent emergence of Delta Plus, which contains a mutation of the already highly-transmissible Delta variant, has led to warnings that Europe could face another summer of social distancing and lockdown measures, especially if further mutated coronavirus strains emerge in the coming weeks and months.
MUTATED CORONAVIRUS MUTATES AGAIN
As spring turned to summer, virologists raised the alarm that the Delta variant had begun to mutate further. On June 11, Public Health England announced that a new strain, termed Delta-AY.1, was identified during genome sequencing analyses.
The new strain, also known as Delta Plus, has been found in at least 10 countries, including the United States, the United Kingdom, India, Portugal, and Switzerland.
As of June 22, 161 cases of Delta Plus have been uploaded to the open-access GISAID database, including 83 cases in the United States, and Public Health England said on Friday that it has identified an additional 41 cases of the new variant.
Delta Plus contains a K417N mutation in the spike protein of the virus that causes COVID-19. This genetic alteration is believed to help the virus bind more easily to lung cells, increasing its transmissibility.
The discovery of Delta Plus, and the potential for as-yet undiscovered SARS-CoV-2 strains to be even more transmissible than the current variants of concern, is cause for worry, Cheryl Walter, a lecturer in microbiology at the University of Hull in the United Kingdom, told Sputnik.
"The prospect that the Delta Plus variant could be even more transmissible and could lead those infected to suffer from more severe COVID-19 symptoms is concerning," Walter said.
Walter added that the new variant could be more resistant to antibodies, making vaccines against the disease less effective.
"Although experimental data is still needed to fully characterize the Delta Plus variant, on paper this virus should not only be more transmissible but could also at least partially evade antibodies produced by the current vaccines that prime your body to make antibodies towards the spike protein," Walter said.
Any increase in the transmissibility of the SARS-CoV-2 virus could lead to the rapid emergence of local COVID-19 clusters that the government would be unable to react to in time, the University of Hull lecturer stated.
David Hughes, an emeritus professor of human & health sciences at the University of Swansea in Wales, said that the mutation to the spike protein would likely boost the transmissibility of the virus, but added that other genetic changes may help these strains become more resistant to vaccines.
"I think that in theory, changes to the spike protein, which are considered crucial because they affect ability to bind to human cells via ACE2 receptors, might coexist with changes elsewhere in the genetic sequence that enhance ability to defeat existing vaccines," Hughes told Sputnik.
CALLS TO SPEED UP MASS VACCINATION PROGRAMS
The emergence of the Delta Plus variant follows on the back of warnings that the existing Delta variant is already more resistant to vaccines against COVID-19 currently in widespread circulation.
In a study published in The Lancet on June 14, Scottish researchers found that a full dosing regimen of Pfizer/BioNTech's COVID-19 vaccine gave 79% protection against the Delta variant, compared to 92% protection against the Alpha variant.
A similar decline in efficacy was reported for AstraZeneca's COVID-19 vaccine, which offers 60% protection against the Delta variant, compared to 73% protection against the Alpha variant, the study found.
The Delta strain may be more effective at evading vaccine antibodies, but Public Health England has said that the vaccines currently in use in the United Kingdom are more than 90% effective in preventing COVID-related hospitalization following infection with the Delta variant.
David Hughes of the University of Swansea stated that the Delta Plus variant would likely cause a similar decline in vaccine efficacy, but added that it was unlikely the new strain would be able to evade the vaccines in circulation.
"My guess is that Delta Plus will not defeat existing vaccines, but may reduce their effectiveness at the margin," Hughes said.
The discovery of the Delta variant in the United Kingdom this past spring prompted opposition lawmakers to criticize the government for failing to impose tougher travel restrictions that may have prevented new strains of the disease from entering the country.
Despite this, Hughes said that there could be a greater risk of vaccine-resistant COVID-19 strains developing in the United Kingdom, where more than half of the country's population has already received one vaccine dose.
"One issue that interests me is whether variants that emerge near home are actually a greater threat than those emerging in say India or Brazil. Because our knowledge is limited, there is a lot of guesswork at present, but my reading of the situation is that it is variants that emerge in the context of a partially-vaccinated population that are the greater risk to us," Hughes said.
The academic stated that COVID-19 strains that were more transmissible were likely to spread quickly through countries that had low vaccination coverage.
In countries with relatively high vaccination coverage, vaccine-resistant strains of the disease could develop if large parts of the population have only received one vaccine dose, Hughes added.
"While a vaccine-defeating virus could in theory emerge anywhere, it is more likely to emerge in the context of a partially-vaccinated population, where it would have a selective advantage over variants that are merely more transmissible, and so would probably not become the dominant variant in a third world country with low vaccine coverage," Hughes said.
As part of efforts to equitably distribute COVID-19 vaccines across the globe, the World Health Organization has called on high-income countries to share vaccine doses with lower-income countries to ensure that at-risk groups, such as medical professionals, are vaccinated as quickly as possible.
Hughes said that national governments should instead speed up efforts to fully vaccinate their populations against COVID-19 to ensure that citizens are fully protected against current variants of concern, adding that this could also prevent the emergence of new, potentially vaccine-resistant strains of the virus.
"To my mind the last thing we want is a largish pool of unvaccinated persons among whom the virus can circulate and mutate while also being capable of infecting some persons who are already vaccinated and mutating in new ways," the University of Swansea academic said.
CRAFTING SECOND-GENERATION VACCINES TO COMBAT COVID-19 VARIANTS
Maria Van Kerkhove, the World Health Organization's technical lead for COVID-19, issued a stark warning on Monday when she told a press briefing that future strains that contain a "constellation of mutations" could render the current vaccines in use ineffective.
Governments across the globe are already putting plans in place to offer booster shots this coming fall, with the intention that individuals would receive updated second-generation vaccines designed to offer protection against new variants of the disease.
The speed at which the SARS-CoV-2 virus is able to mutate may not pose a problem, given the rapid pace at which mRNA vaccines, such as Pfizer/BioNTech's vaccine, can be updated, Cheryl Walter of the University of Hull said.
"The very nature of mRNA vaccines means that the technology can be quickly and safely adjusted to be effective against variants and even predicted variants that have yet to enter circulation," Walter said.
The microbiology lecturer said that the safety profile of any updated vaccine would likely be the same as the original, adding that detailed tests would have to be conducted to ensure that the second-generation vaccines are effective.
The European Union has linked up with German firm CureVac with the aim of producing second-generation mRNA vaccines designed to combat COVID-19 variants.
Last week, CureVac reported that its first-generation vaccine was only 47% effective against 29 COVID-19 strains in a late-stage trial, although the German firm has concluded an agreement with pharmaceutical giant GSK to jointly develop a second-generation vaccine that is set to undergo clinical testing in the third quarter of this year.
NEW VARIANTS COULD TRIGGER NEW LOCKDOWNS
Throughout the spring, many governments across Europe began to lift stay-at-home orders as mass COVID-19 vaccination programs picked up pace.
In England, a handful of social distancing restrictions are still in force, such as the "one meter [3.2 feet] plus" rule. Additionally, open-air events such as sports games are still subject to capacity restrictions, and the country's nightclubs remain closed.
These measures were originally set to be lifted on June 21, although the emergence of the Delta variant and a surge in new cases prompted Boris Johnson's government on June 14 to push back the unlocking by a month.
On Thursday, the UK reported 16,703 new COVID-19 cases. One month earlier, on May 24, only 2,439 positive tests were registered.
Despite the recent rise in the rate of infection, Johnson told reporters on Monday that the prospects for a full unlocking on the new date, July 19, were "looking good."
However, the prime minister also warned that the UK faces "rough winter" if a large-scale influenza outbreak sweeps through the country in December and January.
Cheryl Walter of the University of Hull said that a severe outbreak of Delta Plus COVID-19 cases in the United Kingdom could prompt the government to push back the unlocking date even further.
"If it transpires that this variant is becoming dominant and can significantly avoid the vaccine-mediated immune response, I predict there will be a delay in the lifting of restrictions in the UK," Walter said.
Swansea University's David Hughes said that the potential emergence of vaccine-resistant strains could lead governments to not only delay the lifting of social distancing measures, but also reintroduce some of the tough lockdown restrictions seen in 2020.
"I suspect what we would be looking at if we were unlucky with a vaccine-defeating variant would be further lockdowns, and the kind of race to scale up vaccine supply we've seen already," Hughes said.
Despite the emergence of Delta Plus, the UK is reportedly looking to introduce quarantine-free travel for fully vaccinated individuals.
At present, people arriving from the more than 150 countries on the UK's "amber list" are required to spend 10 days in quarantine in the UK.
Earlier this week, a Department of Health and Social Care spokesperson told Sputnik that the full list of vaccines to be recognized by the UK as part of this proposed scheme was still being finalized.
The UK has so far approved vaccines developed by AstraZeneca, Pfizer/BioNTech, Johnson & Johnson, and Moderna.
