Signs of a community outbreak of infectious diseases are being detected early through wastewater monitoring, with the concentration of the novel coronavirus (COVID-19) virus showing a continuous increase for two weeks. As confirmed cases are rising again in neighboring countries such as China, Thailand, and Singapore, the possibility of a domestic resurgence is being raised.
According to the recent 'Weekly Analysis Report on Wastewater-Based Infectious Disease Surveillance for Week 22 (May 25-31)' released by the Korea Disease Control and Prevention Agency, the concentration of COVID-19 virus has slightly increased compared to the previous week based on the three-week moving average.
This report is based on samples collected from 99 wastewater treatment plants across 17 cities and provinces nationwide. After peaking in early April (Week 14), the concentration of the coronavirus has been decreasing but has rebounded since Week 21 (May 18-24), showing an increase for two consecutive weeks. This has led to interpretations that there are signs of renewed virus transmission within the community.
Jae-gap Lee, a professor of infectious diseases at Hallym University Kangnam Sacred Heart Hospital, said, "Wastewater monitoring serves as an indirect indicator showing the local outbreak situation ahead of the actual number of patients, and a trend of an upswing after hitting a low, like neighboring countries, could be an early signal of resurgence."
In fact, scientists have revealed that analyzing sewage sludge during the COVID-19 pandemic allows for predicting when confirmed cases will increase in densely populated areas about a week in advance.
A research team at Yale University in the U.S. revealed in the international journal 'Nature Biotechnology' in 2020 that analyzing the genetic material (RNA) of the novel coronavirus from sewage sludge in New Haven, Connecticut, with a population of 200,000, could predict trends of increasing confirmed cases about a week in advance.
Professor Lee stated, "We need to wait for the data from Week 23 (June 1-7), which will be released this Friday, to determine the accurate trend, but for now, it is a crucial time for high-risk groups to quickly get vaccinated."
Currently, individuals aged 65 and older, as well as those with weakened immunity aged six months and older and those in vulnerable facilities, can receive the COVID-19 vaccine free of charge until the 30th of this month. The general public can also receive the vaccine at their own expense.
However, the issue is the lack of vaccine supply compared to demand. The current vaccine stock held by the government is only about 850,000 doses. Professor Lee pointed out, "There are about 5 million unvaccinated individuals in high-risk groups, and the government's stockpile of vaccines is grossly insufficient, which could lead to confusion in the healthcare field."
Currently, the COVID-19 variants circulating in the country are LP.8.1 and NB.1.8.1. The government is administering a vaccine against the previously circulating JN.1 variant, and reports indicate that the JN.1 vaccine provides a certain level of prevention against the new variants. However, vaccines tailored to the new variants, including LP.8.1, are expected to be introduced this fall.
Jeong-yeong Mi, the director of the Korea Disease Control and Prevention Agency, noted, "With cases of COVID-19 increasing in neighboring countries, we cannot rule out the possibility of domestic outbreaks this upcoming summer, and high-risk groups planning to travel to China, Thailand, or Singapore are advised to receive vaccination before departure."
References
Infectious Disease Portal, https://dportal.kdca.go.kr/pot/bbs/BD_selectBbs.do?q_bbsSn=1010&q_bbsDocNo=20250605130532613&q_clsfNo=4
Nature Biotechnology (2020), DOI: https://doi.org/10.1038/s41587-020-0684-z