CHICAGO (Reuters). The Delta variant of the SARS-CoV-2 virus is now responsible for the majority of all coronavirus infections worldwide. This is due to the uncontrolled spread of the new coronavirus throughout many parts of the globe. Although vaccines have been able prevent serious illness and death caused by Delta until now, researchers remain on guard.
Here is what we know:
DELTA – STILL DOMINANT
The Delta variant, first discovered in India in December of 2020, remains the most worrisome version of the SARS-CoV-2 virus.
The World Health Organization classifies Delta as a variant of concern, a category that means the variant has the potential to increase the possibility of transmission, leading to more severe diseases or reducing the benefits of vaccines and treatments.
According to Shane Crotty (virologist at La Jolla Institute for Immunology, San Diego), Delta’s “superpower” is its transmissibility.
According to the U.S. Centers for Disease Control and Prevention, Delta is more contagious than the previous SARS-CoV-2 variants. Studies have found that Delta is more likely to be a source of infection for people than previous variants of the virus.
Delta also causes symptoms that last from two to three days earlier than the original coronavirus and gives the immune system less time to build a defense.
The people who are infected by Delta carry approximately 1,200 times more virus in their noses when compared with the original form of the coronavirus. The virus is present in both vaccinated as well as unvaccinated individuals who contract Delta. Both are able to transmit the virus to other people.
For those who have been vaccinated the amount of virus is reduced faster, which means they likely spread the virus for a shorter time.
According to the WHO, Delta accounts for 99.5 percent of all genome sequences that are reported to public databases. It has also “outcompeted” most variants in a majority of countries.
South America is a key exception, where Delta has spread slowly and other variants, previously considered to be threats to the world, such as Gamma, Lambda, and Mu continue to contribute to a significant portion of reported cases.
Due to Delta’s dominance in the world and its influence on vaccines, many experts believe that all future versions will be offshoots of Delta.
One noteworthy Delta “grandchild” is known as AY.4.2 and is found primarily in the UK in the UK, where it is about 10 percent of sequenced virus samples.
AY.4.2 has two additional mutations in the spike protein, which the virus uses to get into cells. Scientists are still studying what benefits, if any, these mutations provide.
The UK Health Security Agency has declared the AY.4.2 as a “Variant Under Investigation”. Although it doesn’t significantly impair vaccine effectiveness A preliminary study has found that it’s not as dangerous as Delta but there are indications that it could be slightly more transmittable.
According to the WHO, AY.4.2 has spread to at least 42 countries, including the United States.
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The experts in Virus are keeping an eye on the evolution of Delta, looking for any indication that it has acquired mutations that could allow the highly transmissible variant to pierce the immune protection offered by natural and vaccines.
Vaccines are not effective in preventing infection. The virus can still replicate in the nose, even among those who have been vaccinated, and are then able to transmit the disease via tiny aerosolized droplets.
According to Dr. Gregory Poland at the Mayo Clinic, in order to defeat SARS-CoV-2, it will likely require new generation of vaccines which also prevent transmission. Until then, Poland and other experts claim that the world is vulnerable.
Content Source: https://www.medscape.com/viewarticle/963030?src=rss