Beautiful Virgin Islands

Thursday, Oct 30, 2025

Delta dominates the world, but scientists watch for worrisome offspring

Delta dominates the world, but scientists watch for worrisome offspring

The Delta variant of the SARS-CoV-2 virus now accounts for nearly all of the coronavirus infections globally, fueled by unchecked spread of the novel coronavirus in many parts of the world. So far, vaccines are still able to defend against serious disease and death from Delta, but scientists remain on alert.

Here is what we know:

DELTA - STILL DOMINANT


The Delta variant, first detected in India in December 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 is capable of increasing transmissibility, causing more severe disease or reducing the benefit of vaccines and treatments.

Delta's "superpower" is its transmissibility, according to Shane Crotty, a virologist at the La Jolla Institute for Immunology in San Diego.

Delta is more than two times as contagious as previous SARS-CoV-2 variants, according to the U.S. Centers for Disease Control and Prevention. Studies suggest it may be more likely to put infected people in the hospital than prior forms of the virus.

Delta also can cause symptoms two to three days sooner than the original coronavirus, giving the immune system less time to mount a defense.

People infected with Delta carry around 1,200 times more virus in their noses compared with the original version of the coronavirus. The amount of virus in vaccinated individuals who become infected with Delta is on par with those who are unvaccinated, and both can transmit the virus to others.

In vaccinated people, however, the amount of virus drops more quickly, so they likely spread the virus for a shorter time.

According to the WHO, Delta makes up 99.5% of all genomic sequences reported to public databases and has "outcompeted" other variants in most countries.

A key exception is South America, where Delta has spread more gradually, and other variants previously seen as possible global threats - notably Gamma, Lambda and Mu - still contribute to a significant proportion of reported cases.

DELTA OFFSPRING


Given Delta's global dominance, many vaccine experts now believe that all future variants will be offshoots of Delta.

One notable Delta "grandchild" is known as AY.4.2 and is concentrated largely in the UK, where it makes up roughly 10% of sequenced virus samples.

AY.4.2 carries two additional mutations in the spike protein, which the virus uses to enter cells. Scientists are still studying what advantage, if any, these mutations confer.

The UK Health Security Agency has designated the AY.4.2 a "Variant Under Investigation." A preliminary analysis suggests it does not significantly impair vaccine effectiveness compared with Delta, but there is some evidence that it could be slightly more transmissible, the agency said.

According to the WHO, AY.4.2 has spread to at least 42 countries, including the United States.

MORE ON THE WAY?


Virus experts are closely watching the evolution of Delta, looking for any sign that it has acquired mutations that would allow the highly transmissible variant to pierce the immune protection of vaccines and natural infection.

Even so, while current vaccines prevent severe disease and death, they do not block infection. The virus is still capable of replicating in the nose, even among vaccinated people, who can then transmit the disease through tiny, aerosolized droplets.

To defeat SARS-CoV-2 will likely require a new generation of vaccines that also block transmission, according to Dr. Gregory Poland, a vaccine developer at the Mayo Clinic. Until then, Poland and other experts say, the world remains vulnerable.

Newsletter

Related Articles

Beautiful Virgin Islands
0:00
0:00
Close
UK and Vietnam Sign Landmark Migration Deal to Fast-Track Returns of Irregular Arrivals
UK Drug-Pricing Overhaul Essential for Life-Sciences Ambition, Says GSK Chief
Princesses Beatrice and Eugenie Temporarily Leave the UK Amid Their Parents’ Royal Fallout
UK Weighs Early End to Oil and Gas Windfall Tax as Reeves Seeks Investment Commitments
UK Retail Inflation Slows as Shop Prices Fall for First Time Since Spring
Next Raises Full-Year Profit Guidance After Strong Third-Quarter Performance
Reform UK’s Lee Anderson Admits to 'Gaming' Benefits System While Advocating Crackdown
United States and South Korea Conclude Major Trade Accord Worth $350 Billion
Hurricane Melissa Strikes Cuba After Devastating Jamaica With Record Winds
Vice President Vance to Headline Turning Point USA Campus Event at Ole Miss
U.S. Targets Maritime Narco-Routes While Border Pressure to Mexico Remains Limited
Bill Gates at 70: “I Have a Real Fear of Artificial Intelligence – and Also Regret”
Elon Musk Unveils Grokipedia: An AI-Driven Alternative to Wikipedia
Saudi Arabia Unveils Vision for First-Ever "Sky Stadium" Suspended Over Desert Floor
Amazon Announces 14 000 Corporate Job Cuts as AI Investment Accelerates
UK Shop Prices Fall for First Time Since March, Food Leads the Decline
London Stock Exchange Group ADR (LNSTY) Earns Zacks Rank #1 Upgrade on Rising Earnings Outlook
Soap legend Tony Adams, long-time star of Crossroads, dies at 84
Rachel Reeves Signals Tax Increases Ahead of November Budget Amid £20-50 Billion Fiscal Gap
NatWest Past Gains of 314% Spotlight Opportunity — But Some Key Risks Remain
UK Launches ‘Golden Age’ of Nuclear with £38 Billion Sizewell C Approval
UK Announces £1.08 Billion Budget for Offshore Wind Auction to Boost 2030 Capacity
UK Seeks Steel Alliance with EU and US to Counter China’s Over-Capacity
UK Struggles to Balance China as Both Strategic Threat and Valued Trading Partner
Argentina’s Markets Surge as Milei’s Party Secures Major Win
British Journalist Sami Hamdi Detained by U.S. Authorities After Visa Revocation Amid Israel-Gaza Commentary
King Charles Unveils UK’s First LGBT+ Armed Forces Memorial at National Memorial Arboretum
At ninety-two and re-elected: Paul Biya secures eighth term in Cameroon amid unrest
Racist Incidents Against UK Nurses Surge by 55%
UK Chancellor Rachel Reeves Cites Shared Concerns With Trump Administration as Foundation for Early US-UK Trade Deal
Essentra plc: A Closer Look at a UK ‘Penny Stock’ Opportunity Amid Market Weakness
U.S. and China Near Deal to Avert Rare-Earth Export Controls Ahead of Trump-Xi Summit
Justin time: Justin Herbert Shields Madison Beer with Impressive Reflex at Lakers Game
Russia’s President Putin Declares Burevestnik Nuclear Cruise Missile Ready for Deployment
Giuffre’s Memoir Alleges Maxwell Claimed Sexual Act with Clooney
House Republicans Move to Strip NYC Mayoral Front-Runner Zohran Mamdani of U.S. Citizenship
Record-High Spoiled Ballots Signal Voter Discontent in Ireland’s 2025 Presidential Election
Philippines’ Taal Volcano Erupts Overnight with 2.4 km Ash Plume
Albania’s Virtual AI 'Minister' Diella Set to 'Birth' Eighty-Three Digital Assistants for MPs
Tesla Unveils Vision for Optimus V3 as ‘Biggest Product of All Time’, Including Surgical Capabilities
Francis Ford Coppola Auctions Luxury Watches After Self-Financed Film Flop
Convicted Sex Offender Mistakenly Freed by UK Prison Service Arrested in London
United States and China Begin Constructive Trade Negotiations Ahead of Trump–Xi Summit
U.S. Treasury Sanctions Colombia’s President Gustavo Petro over Drug-Trafficking Allegations
Miss USA Crowns Nebraska’s Audrey Eckert Amid Leadership Overhaul
‘I Am Not Done’: Kamala Harris Signals Possible 2028 White House Run
NBA Faces Integrity Crisis After Mass Arrests in Gambling Scandal
Swift Heist at the Louvre Sees Eight French Crown Jewels Stolen in Under Seven Minutes
U.S. Halts Trade Talks with Canada After Ontario Ad Using Reagan Voice Triggers Diplomatic Fallout
Microsoft AI CEO: ‘We’re making an AI that you can trust your kids to use’ — but can Microsoft rebuild its own trust before fixing the industry’s?
×