The peer-reviewed study, conducted by researchers at Case Western Reserve University (CWRU) in Ohio, is the first large-scale research effort to compare the health effects of COVID-19 infection from these variants in four-year-olds. and down.
The authors say the findings are significant as the age group is not yet suitable for COVID-19 vaccines and has limited pre-existing immunity.
“The main finding of our study was that many more children became infected with Omicron compared to Delta, but infected children are not as severely affected as children infected with the Delta variant,” said CWRU professor Pamela Davis. in a Press. release.
The findings were published Friday in the medical journal JAMA Pediatrics with reviewers.
The researchers analyzed the electronic health records of more than 651,640 children in the United States who had “medical appointments with health care providers” between September 2021 and January 2022. According to the study, this included more than 22,772 children who became infected with Omicron late. December and late January, as well as more than 66,000 children infected with the Delta variant in the fall.
The researchers also compared the health records of more than 10,000 children before Omicron was detected in the United States, but when Delta was still dominant.
The study looked at the clinical health outcomes for these pediatric patients for 14 days after COVID-19 infection and looked at factors such as emergency visits, hospitalization, ICU admissions and the use of mechanical ventilation.
According to the study, the Omicron variant is six to eight times more contagious than the Delta variant. However, in children under the age of five, less than 2 percent of children infected with Omicron were hospitalized, compared with 3.3 percent of children with Delta.
The researchers report that serious clinical outcomes in infected children aged four and under ranged from a 16 percent lower risk of emergency visits to an 85 percent lower risk of mechanical ventilation.
The researchers also found that children infected with Omicron were, on average, younger and had fewer comorbidities than those infected with Delta.
“We have seen the number of hospitalizations in this age group skyrocket in January of this year, because the Omicron infection rate is about 10 to 15 times higher than that of the Delta variant,” said CWRU professor Rong Xu in announcement.
In addition, Xu said more research is needed to understand the long-term health effects of children infected with COVID-19 variants.
“With so many unvaccinated children infected, the long-term effects of COVID-19 infections on children’s brain, heart, immune system and other organs remain unknown and worrying,” Xu said.
As new variants of COVID-19 continue to emerge, it is unclear how the stealth version of Omicron – the most contagious BA.2 – will affect children in this age group.
Preliminary research from Hong Kong shows that subtype BA.2 is more severe in children than other variants. However, these findings are considered preliminary because they come from a preprint and the study has not yet been reviewed by outside researchers.
According to federal modeling data released Friday, health officials say a resurgence of COVID-19 is under way in Canada.
The Public Health Service of Canada says BA.2 subtype, declining human immunity and a return to more personal activities appear to be linked to the current rise.
