Vaccine effectiveness in symptom and viral load mitigation in COVID-19 breakthrough infections in South Korea.

OBJECTIVES: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine effectiveness in coronavirus disease (COVID-19) patients with breakthrough infections has not been established in South Korea. To address this, we assessed the impact of vaccination on symptom occurrence and viral load. METHODS: We performed a retrospective cohort study of 9,030 COVID-19 patients enrolled between February and November 2021. The impact of vaccination on the incidence of symptoms and viral load as indicated by cycle threshold (Ct) values of RdRp and E genes was evaluated using relative risks (RRs) and 95% confidence intervals (95% CIs). RESULTS: Compared with unvaccinated patients, fully vaccinated patients were associated with a reduced symptom onset of cough, sputum, and myalgia in COVID-19 patients (RR (95% CI) = 0.86 (0.75-0.99) for cough; RR (95% CI) = 0.74 (0.56-0.98) for sputum; RR (95% CI) = 0.65 (0.53-0.79) for myalgia, respectively). Additionally, lower risk of high viral load, Ct value of RdRp gene <15 or Ct value of E gene <15, was observed especially in fully vaccinated patients younger than 40 years ((RR (95% CI) = 0.69 (0.49-0.96) for RdRp gene; (RR (95% CI) = 0.71 (0.53-0.95) for E gene). CONCLUSION: SARS-CoV-2 vaccination was associated with a reduced risk of COVID-19 symptoms as well as decreased viral load, especially in patients younger than 40 years.

Evaluation of the Diagnostic Accuracy of Nasal Cavity and Nasopharyngeal Swab Specimens for SARS-CoV-2 Detection via Rapid Antigen Test According to Specimen Collection Timing and Viral Load.

The rapid diagnosis of SARS-CoV-2 is an essential aspect in the detection and control of the spread of COVID-19. We evaluated the accuracy of the rapid antigen test (RAT) using samples from the nasal cavity and nasopharynx based on sample collection timing and viral load. We enrolled 175 patients, of which 71 patients and 104 patients had tested positive and negative, respectively, based on real time-PCR. Nasal cavity and nasopharyngeal swab samples were tested using STANDARD Q COVID-19 Ag tests (Q Ag, SD Biosensor, Korea). The sensitivity of the Q Ag test was 77.5% (95% confidence interval [CI], 67.8−87.2%) for the nasal cavity and 81.7% (95% [CI, 72.7−90.7%) for the nasopharyngeal specimens. The RAT results showed a substantial agreement between the nasal cavity and nasopharyngeal specimens (Cohen's kappa index = 0.78). The sensitivity of the RAT for nasal cavity specimens exceeded 89% for <5 days after symptom onset (DSO) and 86% for Ct of E and RdRp < 25. The Q Ag test performed fairly well, especially in the early DSO when a high viral load was present, and the nasal cavity swab can be considered an alternative site for the rapid diagnosis of COVID-19.

The Lived Experiences of COVID-19 Patients in South Korea: A Qualitative Study.

The purpose of this qualitative study is to provide an in-depth understanding and description of the disease experiences of COVID-19 patients. The participants were 16 patients discharged from hospitals after receiving treatment for COVID-19 in isolation. Data collection was conducted through individual in-depth interviews until data saturation, and the interviews were recorded and transcribed verbatim. Data were analyzed using Colaizzi's phenomenological method. The participants were quarantined after their COVID-19 diagnosis was confirmed, and they experienced desperate and uncertain times during treatment. The participants expressed shock and dissatisfaction due to an excessive invasion of privacy during the quarantine process and in the quarantine system. As confirmed COVID-19 cases, the participants experienced social stigma and feelings of guilt, negative attitudes from others and society, and negative influences from social networking services and the media. The participants also experienced mental and physical difficulties due to COVID-19 symptoms. However, they rediscovered meaningful relationships through the support of their family and friends in the midst of adversity. It is necessary to provide an integrated psychosocial rehabilitation program to reduce social stigma and improve the resilience of COVID-19 patients.