Reinfection Rate Surges Over 10 Times After Omicron Variant Emerges [Reading Science]

UK Research Team Finds 650,000 Reinfections in Last Two Months
Proportion of Reinfections Among All Patients Rises from 1% to 10%

On the 8th, when the number of new COVID-19 cases remained in the 30,000s for the fourth consecutive day, citizens are receiving rapid antigen tests at a temporary screening clinic in front of Seoul Station. Photo by Mun Ho-nam munonam@

[Asia Economy Reporter Kim Bong-su] Since the emergence of the Omicron variant, the number of COVID-19 reinfection cases has surged worldwide. Scientists believe this is because the Omicron variant has a superior ability to evade antibodies formed by infection and vaccination compared to previous variants. Fortunately, there is some relief in the fact that despite its strong transmissibility, its toxicity is less than 10% of that of earlier variants.

According to the international academic journal 'Nature' on the 17th, the UK Health Security Agency reported that 650,000 COVID-19 reinfection cases occurred in the past two months. Until November last year, the reinfection rate among all COVID-19 patients was about 1%, but recently it has surged more than tenfold to 10%. The UK Office for National Statistics also announced that comparing the period from mid-December last year to early January this year, when the Omicron variant became dominant, with the previous seven months dominated by the Delta variant, the risk of reinfection was 16 times higher. Earlier, a study conducted on about 2,797,000 patients in South Africa found that the reinfection risk rates for the Beta and Delta variants were low at 0.75 and 0.71 respectively, but the reinfection risk rate for the Omicron variant was as high as 2.39, indicating a much higher risk.

Scientists attribute this spread of reinfections to the Omicron variant's exceptional ability to evade the human immune system. While previous variants had 12 mutations in the spike protein that binds to the human body to infect the virus, Omicron has more than 32 mutations.

This immune evasion ability of the Omicron variant is also confirmed in actual clinical statistics. According to a paper by a Qatar research team published this month in the 'New England Journal of Medicine,' people with antibodies from previous infections are 90% protected against the Alpha, Beta, and Delta variants, but protection against the Omicron variant is only 59%.

However, the Qatar research team also found positive facts. Most reinfections occur on an annual basis, meaning antibodies formed from previous infections are effective for a certain period, and notably, the prevention effect against severe disease caused by the Omicron variant reaches 88%. However, there is a counterargument that since most Omicron cases are asymptomatic or mild, the protection rate calculated by the research team may be overestimated.

Abu Raddad, an infection specialist from the Qatar research team, said, "The Omicron variant has the ability to infect people who have immunity triggered by previous infection or vaccination, and this is the core reason for recent reinfections," adding, "The immune evasion ability of the Omicron variant is truly different from other variants."

Catherine Bennett, a professor at Deakin University in Australia, also analyzed, "Various factors have influenced the surge in reinfections. Many people may have been exposed to the virus more due to the rapid spread of the Omicron variant, increasing the risk of reinfection," and added, "The immune evasion ability of the Omicron variant plays an important role."