Delta variant spreading more in US

The Delta variant of the coronavirus, which public health officials say is particularly risky to people who are unvaccinated, especially young people, will probably make up 50 percent of coronavirus infections in the US by early to mid-July, according to a new study.

Dr William Lee, vice-president of science at population genomics company Helix in San Mateo, California, and an author of the study, said that the Delta variant was spreading fastest in counties with low vaccination rates.

The study by Helix, which is under contract with the US Centers for Disease Control and Prevention (CDC) to help track variants, hasn't yet been peer-reviewed but has been posted on a pre-print server.

Lee said he expected prevalence of the Delta variant to plateau in the US at about 70 percent to 80 percent of coronavirus cases.

"Just the fact that it's so transmissible means that it's dangerous," Lee said, "and so I think you'll see outbreaks of Delta around the country, and more people will get sick from it," he told MSN.

The super-contagious Delta variant is now responsible for about 1 in every 5 coronavirus cases in the US, and its prevalence has doubled in the last two weeks, health officials said on Tuesday.

The Delta variant, first detected in India, is accounting for half of new infections in regions that include Iowa, Kansas, Missouri, Nebraska, Colorado, Montana, North Dakota, South Dakota, Utah and Wyoming, the CDC said.

In Springfield, Missouri, the low rate of COVID-19 vaccinations combined with the Delta variant has led to a sixfold increase in hospitalizations at CoxHealth, a healthcare system there, according to its CEO, Steve Edwards.

Over the past four and a half weeks, the number of patients has risen from around 14 to 83, Edwards told CNN on Monday, adding that the patients are younger and have more severe disease than previously and almost all are unvaccinated.

The Delta variant made up about 10 percent of cases that were tested three or four weeks ago, he said. "As of last week, it appeared to be 90 percent."

The cases have put new pressure on his staff, Edwards said, compared to previous outbreaks.

"It is harder to know that you're risking your well-being for someone that chose not to vaccinate, that then puts you and them at risk."

Health officials say it is unclear how much of a problem Delta will cause in the US, but its rapid spread has prompted concerns that it might jeopardize the nation's progress in beating back the pandemic.

"The Delta variant is currently the greatest threat in the US to our attempt to eliminate COVID-19," Dr Anthony S. Fauci, director of the National Institute of Allergy and Infectious Diseases, said Tuesday at a White House briefing.

He said on CBS This Morning on Wednesday that the Delta variant could be the dominant strain in areas of the US that have low vaccination rates in a matter of weeks.

While the variant spreads more efficiently, and data from the UK indicate that it makes people more seriously ill, Fauci said the vaccines in use in the US work well against it.

"It will be the dominant strain among those areas, those regions of the country where the vaccination rate is lower than we would like," Fauci said. "For those areas where you have a high vaccination rate, you're not going to see that. Again, another powerful reason why we need to get vaccinated."

As of Tuesday night, 65.5 percent of the adult population in the US had received at least one dose of a COVID-19 vaccine, according to the CDC.

Fewer than half of the adults in Alabama, Louisiana, Mississippi and Wyoming have received at least one dose of the vaccine, according to data from the CDC.

Meanwhile, a CDC advisory committee said on Wednesday that there is a "likely association" between cases of heart inflammation and the Pfizer and Moderna COVID-19 vaccines in adolescents and young adults.

"Clinical presentation of myocarditis cases following vaccination has been distinct, occurring most often within one week after dose two, with chest pain as the most common presentation," Dr Grace Lee, a member of the Advisory Committee on Immunization Practices, said at the meeting.

More than 1,200 preliminary cases of myocarditis and pericarditis have been recorded in the federal Vaccine Adverse Event Reporting System (VAERS) as of June 11, according to CDC data.