Preliminary findings from two clinical trials in South Africa suggest that the Omicron coronavirus variant has a much higher rate of “asymptomatic carriage” than the earlier variant, which may explain why it has spread so rapidly around the world. has gone.
Studies found that a much higher number of people tested positive for the coronavirus but were not showing symptoms compared to previous tests.
In an Ubuntu study evaluating the efficacy of Moderna’s COVID-19 vaccine in people living with HIV, 31 percent of 230 participants undergoing screening tested positive, with all 56 samples sequenced. Available for analysis, verified as Omicron.
This is “in contrast to the positivity rate pre-Omicron,” which ranges from less than one percent to 2.4 percent, the researchers said in a statement.
In a subgroup of the Sissonke trial evaluating the efficacy of Johnson & Johnson’s COVID-19 vaccine, the average asymptomatic carriage rate increased from 2.6 percent during the beta and delta outbreaks to 16 percent during the Omicron period.
The researchers said, “Sisonke’s study involved 577 subjects who had previously been vaccinated …
He added that “the high asymptomatic carriage rate is potentially a major factor in the rapid and widespread spread of the variant, even among populations with high prior rates of coronavirus infection.”
South Africa experienced a surge in COVID-19 infections since late November, around the time its scientists alerted the world to Omicron.
But new cases have dwindled and there are early signs that the wave has been marked by less severe disease than previously thought.