Sung HK, et al. J Korean Med Sci. 2020 Jul;35(30):e280. https://doi.org/10.3346/jkms.2020.35.e280

Influenza is a communicable disease primarily caused by influenza A or B viruses. It is a common acute respiratory illness that tends to spread during the winter season in Korea. Transmission occurs through respiratory droplets emitted from infected subjects. The basic reproduction number, which is defined as the average number of secondary cases per case in a totally susceptible population, has been observed to range from 1.27 to 1.8 in the four pandemics since the 20th century and during seasonal influenza epidemics [1]. Influenza poses a high risk of complications and can result in serious clinical outcomes in vulnerable populations, such as those aged 65 and above, children, and people with chronic diseases. It also increases absenteeism rates at workplaces and schools, and rapidly increases the demand for medical care, significantly impacting society from a public health perspective.

Gim H, et al. J Korean Med Sci. 2024 May;39:e174. https://doi.org/10.3346/jkms.2024.39.e174

There is a paucity of data regarding the differentiating characteristics of patients who were infected with Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) by fomites around the world. We conducted an event-based outbreak investigation, involving 795 public officers and 277 assistant staff, in the Ministry of Oceans and Fisheries (MOF) or the same building from March 2 to March 18, 2020. The SARS-CoV-2 patients were found to have more frequently touched fomites and used public toilets than those who were tested negative for the virus (cOR, 24.38; 95% CI, 4.95–120.01). Symptoms such as coughing and loss of taste and smell were more frequently found in the office-cleaner group than in the public-officer group. The SARS-CoV-2 office-cleaner patients were more likely to have a high RdRp(Ct) value of PCR (median: 34.17 vs. 24.99; p = 0.035) and E(Ct) value of PCR (median: 32.30 vs. 24.74; p = 0.045). All office cleaner patients (100%) had a ground glass opacity in both lobes. Regarding segmental lung involvement of CT, two patients (100%) had a lesion in the right middle lobe, which invaded the whole lobe later. This implies that the fomite might be a selective risk factor of SARS-CoV-2 infection.

Seok J, et al. Yonsei Med J. 2022 Aug;63(8):707-716. https://doi.org/10.3349/ymj.2022.63.8.707

(1) Background: There is a paucity of data regarding the validity of rapid antibody testing for SARS-CoV-2 vaccine response in homeless people worldwide. The objective of this study was to evaluate a rapid SARS-CoV-2 IgM/IgG antibody detection kit as a qualitative screen for vaccination in homeless people. (2) Methods: This study included 430 homeless people and 120 facility workers who had received one of BNT162b2, mRNA-1273, AZD1222/ChAdOx1, or JNJ-78436735/AD26.COV2.5 vaccines. They were tested for IgM/IgG antibodies to the SARS-CoV-2 spike protein with the STANDARD™ Q COVID-19 IgM/IgG Plus Test (QNCOV-02C). ELISA/competitive inhibition ELISA (CI-ELISA) was subsequently run to assess the validity of the serological antibody test. (3) Results: The sensitivity of homeless people was 43.5%. The status of homelessness was related to a lower agreement between serological antibody testing and CI-ELISA (adjusted OR (aOR), 0.35; 95% CI, 0.18–0.70). However, the Heterologous boost vaccine presented higher agreement between serological antibody testing and CI-ELISA (adjusted OR (aOR), 6.50; 95% CI, 3.19–13.27). (4) Conclusions: This study found weak agreement between the rapid IgG results and confirmatory CI-ELISA testing in homeless people. However, it can be used as a screening test for the acceptance of homeless people with heterologous boost vaccination in facilities.