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Recently, the number of new corona patients is increasing again not only in Korea but also around the world. As the sub-mutation of Omicron, which evades the existing immunity, is rapidly spreading, the number of reinfected patients is increasing.

Reinfection was usually mild.

Still, a study found that high-risk groups, such as the elderly and dialysis patients, were more at risk than the first infection.



This is Cho Dong-chan, a medical reporter.



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BA.5, which is rapidly spreading in Korea, is already the dominant species in the United States.



In a survey of 257,000 confirmed cases in the United States in the past six months, 15% were reinfected, and most were BA.5 mutations.



Compared to the reinfection rate of less than 1.5% for delta and omicron mutations, this is more than 10 times, because BA.5 has the greatest ability to evade existing immunity.



In addition, a study from the University of Washington in the United States found that healthy people were mildly ill even after being re-infected with BA.



Reinfection was more than twice as likely to cause pneumonia, heart and bleeding complications as the initial infection, and for this reason the hospitalization rate was three times higher and the fatality rate was 2.14 times higher.



It overturns the conventional wisdom that symptoms will be weak during the second or third infection by gaining immunity after infection.



The high-risk group was seriously ill at the time of the first infection and was re-infected in a state in which health was compromised, the research team estimated that the fatality rate increased.



The characteristic of BA.5 penetrating into the lungs and heart better than the conventional Omicron was also prominent in the high-risk group.



The risk of reinfection in the high-risk group was similar regardless of the number of vaccinations.



[Bang Ji-hwan/Professor of Infectious Diseases, Seoul National University Boramae Hospital: Healthy people may or may not be re-infected, but it passes very slightly.

High -risk groups do not have long immunity even if they receive a vaccine or are naturally infected.]



With the spread of BA.5 mutations, more special prevention measures are needed for high-risk groups.