Delta, a subtype of the SARS-CoV-2 virus, continues to spread quickly around the world. What do we currently know about this variant?
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Scientists detected the delta form of SARS-CoV-2 — technically called the B.1.617.2 lineage — for the first time in December 2020 in India.
In April 2021, the delta variation was identified as the most frequently occurring variant responsible for new COVID-19 cases in India. Since then, the World Health Organization reports that this variation has been documented in 80 countries (WHO).
Recently, there has been worry — notably in the United Kingdom and the United States — that the delta variant might spark another COVID-19 wave, impeding national and international attempts to relax pandemic restrictions.
According to the most recent data from Public Health England (PHE), the delta variation may have established itself as the dominant variant in the United Kingdom, accounting for “74 percent of sequenced cases [of SARS-CoV-2 infection] and 96 percent of sequenced and genotyped cases.”
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In the United States, the Centers for Disease Control and Prevention (CDC) reported that 2.7 percent of new COVID-19 cases were linked to the delta variant. This is the most latest genetic surveillance data, spanning the period ending May 22, 2021, by two weeks.
Recently, former Food and Drug Administration (FDA) Commissioner Dr. Scott Gottlieb stated that the delta variation accounts for around 10% of new COVID-19 cases.
Dr. Anthony S. Fauci, director of the National Institute of Allergy and Infectious Diseases, has allegedly cautioned that “any country with the delta variation should be concerned about a rise in infections, particularly if that country does not have a high vaccination rate.”
“We’ve found that when the delta variation spreads among unvaccinated individuals, it may soon become dominant,” he added.
Is the delta variation highly contagious?
According to research from the United Kingdom, the delta version is around 60% more transmissible than the alpha form, previously known as B.1.1.7. As result, Alpha is more transmissible than the strain that was previously prevalent in the nation.
Prof. Wendy Barclay, professor of virology and director of Imperial College London’s Department of Infectious Disease, stated that this variation is more transmissible than earlier ones due to many critical changes in the spike protein, which enables the virus to infiltrate and infect healthy cells.
“The delta variation contains two significant mutations, or sets of mutations, in its spike protein,” she said. “The first is at the furin cleavage site, which we believe is critical for the virus’s fitness in the airway.”
“Because the virus that developed in Wuhan was poor in that regard, it spread, albeit not as effectively as it might. With a specific mutation, the alpha version took a first step toward enhancing it, and the delta variant has built on that and done a second, larger step toward improving that feature,” Prof. Barclay explained.
Are the signs of infection distinct?
Additionally, data obtained by British scientists show that the major symptoms associated with infection with the delta form of SARS-CoV-2 are distinct from those associated with infection with earlier versions.
Thus, according to data from the ZOE Covid Symptom Study — which was analyzed scientifically by researchers at King’s College London — the primary symptoms of infection with the delta form include headaches, a sore throat, and a runny nose.
This is in contrast to official information on COVID-19 symptoms, such as that published by the United Kingdom’s National Health Service (NHS), which includes fever, persistent coughing, and loss of smell or taste as the condition’s primary symptoms.
Prof. Tim Spector, the co-founder of ZOE, cautions that SARS-CoV-2 infections are now “behaving differently, more like a nasty cold,” which may lead individuals to disregard the symptoms.
“It may seem like a nasty cold or some other ‘off’ feeling — but please remain at home and be tested,” he advises.
What are the hazards in the future?
Recently, a group of experts in the United Kingdom advocated for the reinstatement of tougher safety measures in schools to halt the spread of the delta strain.
Given the enhanced transmissibility of delta, several scientists have speculated that this might raise the possibility of another COVID-19 outbreak.
Imperial College London modeling estimates show that the delta variation may considerably raise the likelihood of COVID-19 hospitalizations, exposing the United Kingdom to the prospect of a third wave similar to the one seen last winter.
Following alarming indications of the spread of this strain, the British government has already postponed by four weeks the conclusion of the country’s pandemic restrictions.
Dr. Gottlieb further cautioned that the United States might see additional COVID-19 outbreaks as a result of this highly transmissible strain.
“I believe that in areas of the country with lower vaccination rates, notably in the South, where certain cities have poor vaccination rates, there is a danger of outbreaks with this new variant,” he stated.
As such, he urged individuals to get completely immunized against COVID-19, adding that the vaccinations presently approved in the United States appear to be effective against the new form.
“The mRNA vaccine [Pfizer-BioNTech and Moderna] appears to be extremely effective against this variation, with two doses. Additionally, the viral vector vaccines developed by [Johnson & Johnson] and AstraZeneca look to be successful, at around 60% effectiveness. mRNA vaccinations are around 88% effective. As a result, we have the instruments necessary to contain and fight it. We just need to employ those tools,” he added.