London 17 Aug, London : The risk of reinfections caused by Covid-19, the Omicron variation of Covid-19 is much more prevalent than previously believed according to an investigation in Iceland. Reinfection can be defined as the presence of a positive PCR test for SARS-CoV-2a-60 and more days after a positive test.
The study, which was published in JAMA Network Open, unexpectedly revealed that multiple doses of vaccine were associated with an increase in the risk of reinfection than those with one dose or less.
However the “finding must be interpreted with caution due to of the limitations of our research, such as the inability of adjusting for the complicated relationships between prior infections or vaccine eligibility as well as the underlying conditions,” Elias Eythorsson, from Landspitali-The National University Hospital of Iceland wrote in the paper.
The study team analyzed 11,536 PCR-positive individuals.Reinfection was detected in 1 327 individuals (11.5 percent) in the Omicron period.
Of those who had received one dose or less of vaccine, 11.7 per cent (1,007 of 8,598 people) were infected again in comparison with 10.9 percent (320 of 2,938 individuals) who had received two or more doses.
While the incidence of reinfections among older people were lower, the rate was the highest (475 of 3,136 individuals [15.1 percent) in the between 18 and 29 years old according to the research.
The risk of the possibility of recurrence also increased with the time since the first infection and was more common among people who had taken two or more doses as opposed to a single dose of vaccine or less, the researchers noted.
“Longer time between the initial infection was associated with higher risk of reinfection, even though the difference was not as anticipated,” Eythorsson said.
“Our findings suggest that reinfection is more prevalent than we previously believed.The question now is whether infection with the Omicron variant will provide more defense against Omicron reinfection, as compared with different variants.” Eythorsson added.
Omicron was first discovered by South African researchers in November last year, is believed to defy immunity caused by vaccination and prior infections, which makes reinfections more frequent.
The protection of previous infections against re-infection with Omicron is estimated to be 56 percent as compared with 92 percent with the Delta variant.
rvt/sks/bg
.
