With a replacement wave of Covid-19 infections fueled by the Delta variant striking countries worldwide, disease experts are scrambling to find out whether the newest version of coronavirus is making people — mainly the unvaccinated — sicker than before.
The US Centres for Disease Control and Prevention warned that Delta, first identified in India and now dominant worldwide, is “likely more severe” than earlier versions of the virus, consistent with an indoor report made public on Friday.
The agency cited research in Canada, Singapore, and Scotland showing that folks infected with the Delta variant were more likely to be hospitalized than patients earlier within the pandemic.
In interviews, disease experts said the three papers suggest a greater risk from the variant, but the study populations are limited and therefore the findings haven’t 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 serious cases.
But the experts said more work is required to match outcomes among larger numbers of people in epidemiologic studies to map out whether one variant causes more severe disease than another.
“It’s difficult to pin down increase in severity and population bias,” said Lawrence Young, a virologist at the UK’s Warwick school of medicine .
In addition, it’s likely that the extraordinary rate of Delta transmission is additionally contributing to a greater number of severe cases arriving at hospitals, the experts said.
Delta is as contagious as chickenpox and much more contagious than the cold or flu, consistent with 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 severe disease comes from the Scotland study, which found that Delta roughly doubled the danger of hospitalisation compared to an earlier version.
The majority of hospitalisations and deaths from coronavirus within the us are occurring in people that haven’t been vaccinated. But there’s evidence that the shots are less effective in people with compromised immune systems, including the elderly.
For vaccinated, otherwise healthy individuals, the chances are that if they contract Covid-19 they’re going to only experience asymptomatic or mild disease, said Dr Gregory Poland, communicable disease expert at the Mayo Clinic.
“But they will pass it on to relations et al. who might not be so lucky,” Poland said. “We need to be vaccinated and masked or we’ll , for the fourth time now, endure another surge and out of which will come worse variants.”
The rate of severe illness, especially in regions where vaccination rates are low, is again straining healthcare workers on the front lines of the pandemic.
“This is sort of a wildfire, this is often not a smoldering campfire. it’s full-on flames immediately ,” said Dr. Michelle Barron, senior medical director of infection prevention and control at Colorado’s UCHealth.
