Management of Contacts of the First Imported Monkeypox Case in Korea.

On 22 June, a man who returned to South Korea from Germany tested positive for the monkeypox virus using real-time polymerase chain reaction. We identified 49 contacts concerning the first monkeypox case and classified them into two groups based on risk exposure levels. Through active monitoring of eight people in the medium-risk group and passive monitoring of 41 people in the low-risk group, we identified that no secondary transmission occurred over 21 days. The prompt active or passive monitoring of the index case of imported monkeypox could prevent community transmission in Korea.

An outbreak of SARS-CoV-2 reinfection in a long-term care facility in South Korea.

We report a cluster of 12 cases of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) reinfection in a long-term care facility in South Korea. There were two outbreaks of SARS-CoV-2 infection in the facility at the beginning and end of October 2021, respectively. All residents in the facility were screened for SARS-CoV-2 infection using RT-PCR as part of the investigation of the second outbreak. Twelve residents, who had infection confirmed during the first outbreak, were found to be re-positive for RT-PCR test at the second outbreak. 8 Of 12 RT-PCR re-positive cases were confirmed as reinfections based on investigation through the whole genome sequencing, viral culture, and serological analysis, despite of the short interval between the first and second outbreaks (29-33 days) and a history of full vaccination for 7 of the 12 re-positive cases. This study suggests that decreased immunity and underlying health condition in older adults makes them susceptible to reinfection, highlighting the importance of prevention and control measures regardless of vaccination status in long-term care settings.

Herd immunity: challenges and the way forward in Korea.

Vaccination is considered to be the most effective measure for preventing the spread of coronavirus disease 2019 (COVID-19). Many countries, including of Korea, are focusing on achieving herd immunity with the goal of reaching a vaccination rate of 70-80%. However, achieving herd immunity does not mean eradicating COVID-19, and the following challenges can occur in the process of achieving herd immunity. First, as the vaccination rate is likely to slow down over time, it is necessary to promote the benefits of vaccination through risk communication strategies and provide incentives for those who have been vaccinated. Second, a booster dose may be required depending on future studies on vaccine-induced immunity. Third, since variants capable of evading immunity and with higher transmissibility can emerge, rapid contract tracing and regular community genomic surveillance could help mitigate the impact of new variants. When the impact of COVID-19 is controlled to the level of seasonal influenza, the current public health measures that have been strictly imposed on society since the beginning of the pandemic will no longer be needed. The overall response strategy to COVID-19 will need to change accordingly, based on evaluations of the level of population immunity. These changes will include more efficient and targeted contact tracing and eased quarantine measures for vaccinated close contacts and travelers. Mask wearing and a minimum of social distancing will still be required in the journey towards the end of the pandemic. The COVID-19 pandemic will end, but the virus will not disappear.