Highly contagious Delta variant gaining ground in US

The highly transmissible Delta variant of SARS-CoV-2, first identified in India, has become the most prevalent variant among new COVID-19 cases in the United States, according to California-based genomics company Helix.

The company's computer models indicate that Delta now accounts for around 40% of new US cases, Dr. William Lee, vice president of science at Helix, said in a statement provided to Reuters.

The models, based on 27,717 virus samples from 687 counties across the United States, also indicated that the worrisome Gamma variant, first identified in Brazil, accounts for about 15% of new cases.

Helix researchers have noted occasional cases of an "offspring" variant of Delta called Delta-plus, but they "aren't seeing any evidence suggesting that these are driving the growth of Delta around the country yet," Lee said.

Earlier in June, the researchers reported on the medical website medRxiv ahead of peer review that the percentage of new COVID-19 cases due to the variant first identified in Britain, known as Alpha, had dropped from 70% in mid-April 2021 to 42% six weeks later.

Now, Lee said, Alpha "is down to around 20%." Lee said his team has submitted an update to the previous medRxiv preprint and is waiting for approval.  -- Reuters