© Reuters. FILE PHOTO: A lone bird passes the quiet Circular Quay train station during a shutdown to slow the spread of a coronavirus (COVID-19) outbreak in Sydney, Australia, on July 28, 2021. REUTERS / Loren Elliott / File Photo
By Deena Beasley
LOS ANGELES (Reuters) – With a new wave of COVID-19 infections driven by the Delta variant affecting countries around the world, disease experts are scrambling to know whether the latest version of the coronavirus is making people, mainly those not vaccinated, are sicker than before.
The US Centers for Disease Control and Prevention warned that Delta, first identified in India and now dominant worldwide, is “probably more severe” than previous versions of the virus, according to an internal report. made public on Friday.
The agency cited research in Canada, Singapore and Scotland showing that people infected with the Delta variant were more likely to be hospitalized than patients before the pandemic.
In interviews with Reuters, disease experts said all three articles suggest an increased risk of the variant, but study populations are limited and the findings have not yet been reviewed by outside experts. Doctors treating patients infected with Delta described a more rapid onset of COVID-19 symptoms and, in many regions, an overall increase in severe cases.
But experts said more work is needed to compare the results among larger numbers of people in epidemiological studies to determine whether one variant causes a more serious disease than another.
“It’s difficult to pin down the increased severity and population bias,” said Lawrence Young, a virologist at Warwick School of Medicine in the UK.
In addition, the extraordinary Delta transmission rate is also likely contributing to more serious cases reaching hospitals, experts said.
Delta is as contagious as chickenpox and much more contagious than the common cold or flu, according to the CDC report.
Shane Crotty, a virologist at the La Jolla Institute for Immunology in San Diego, said the clearest indication that the variant may cause more serious disease comes from the Scotland study, which found that Delta nearly doubled the risk of hospitalization compared to a earlier version.
Most coronavirus hospitalizations and deaths in the United States occur in people who have not been vaccinated. But there is evidence that vaccines are less effective in people with compromised immune systems, including the elderly.
For otherwise healthy vaccinated people, if they contract COVID-19 they will most likely experience only mild or asymptomatic illness, said Dr. Gregory Poland, an infectious disease expert at Mayo Clinic.
“But they can pass it on to family members and other people who may not be so lucky,” Poland said. “We have to be vaccinated and masked or, for the fourth time, we will endure another wave and worse variants will emerge from there.”
The rate of serious illness, especially in regions where vaccination rates are low, puts pressure on healthcare workers on the front line of the pandemic again.
“This is like a wildfire, this is not a burning campfire. It’s full of flames right now,” said Dr. Michelle Barron, senior medical director of infection prevention and control at UCHealth Colorado.
Research from China suggesting that the Delta variant replicates much faster and generates 1,000 times more virus in the body compared to the original strain, highlights the greater danger of this new wave, Barron said.
“It’s difficult to know if they are sicker because of the Delta variant or if they would have been sicker anyway,” he said.
Other doctors said patients infected with Delta appear to fall ill more quickly, and in some cases with more severe symptoms, than those they treated earlier in the pandemic.
“We are seeing more patients requiring oxygen sooner,” said Dr. Benjamin Barlow, medical director of American Family Care, a chain of urgent care clinics in 28 states.
At his clinic in Birmingham, Alabama, Barlow said that about 20% of patients test positive for COVID-19, compared to 2-3% a few weeks ago. At that time, patients are evaluated for possible hospital admissions and oxygen support.
David Montefiori, director of the Laboratory (NYSE 🙂 for AIDS Vaccine Research and Development at Duke University Medical Center, said the Delta variant is more infectious and leads to a more rapid onset of the disease, particularly for the unvaccinated.
“Frankly, there is a severity that comes from this variant that is a bit more serious,” Montefiori said in a webcast last week. “Not only is it easier to transmit, it makes you sicker.”