Effect of Previous COVID-19 Vaccination on Humoral Immunity 3 Months after SARS-CoV-2 Omicron Infection and Booster Effect of a Fourth COVID-19 Vaccination 2 Months after SARS-CoV-2 Omicron Infection.

In this study, we aimed to determine the effect of COVID-19 vaccination on 3-month immune response and durability after natural infection by the Omicron variant and to assess the immune response to a fourth dose of COVID-19 vaccination in patients with prior natural infection with the Omicron variant. Overall, 86 patients aged ≥60 years with different vaccination histories and 39 health care workers (HCWs) vaccinated thrice before Omicron infection were enrolled. The sVNT50 titer was significantly lower in patients with incomplete vaccination before SARS-CoV-2 infection with the S clade (p < 0.001), Delta variant (p < 0.001), or Omicron variant (p = 0.003) than in those vaccinated thrice. The sVNT results against the Omicron variant did not differ significantly in patients aged ≥60 years (p = 0.49) and HCWs (p = 0.17), regardless of the recipient receiving the fourth dose 2 months after COVID-19. Incomplete COVID-19 vaccination before Omicron infection for individuals aged ≥60 years conferred limited protection against homologous and heterologous virus strains, whereas two or three doses of the vaccine provided cross-variant humoral immunity against Omicron infection for at least 3 months. However, a fourth dose 2 months after Omicron infection did not enhance immunity against the homologous strain. A future strategy using the bivalent Omicron-containing booster vaccine with appropriate timing will be crucial.

Fluvoxamine Treatment of Patients with Symptomatic COVID-19 in a Community Treatment Center: A Preliminary Result of Randomized Controlled Trial.

BACKGROUND: This study aimed to evaluate whether fluvoxamine reduces clinical deterioration in adult patients with mild to moderate coronavirus disease 2019 (COVID-19), and to identify risk factors for clinical deterioration in patients admitted to a community treatment center (CTC). MATERIALS AND METHODS: A randomized, placebo-controlled trial was conducted in a CTC, in Seoul, Korea from January 15, 2021, to February 19, 2021. Symptomatic adult patients with positive results of severe acute respiratory syndrome coronavirus 2 real time-polymerase chain reaction within 3 days of randomization were assigned at random to receive 100 mg of fluvoxamine or placebo twice daily for 10 days. The primary outcome was clinical deterioration defined by any of the following criteria: oxygen requirement to keep oxygen saturation over 94.0%, aggravation of pneumonia with dyspnea, or World Health Organization clinical progression scale 4 or greater. RESULTS: Of 52 randomized participants [median (interquartile range) age, 53.5 (43.3 - 60.0) years; 31 (60.0%) men], 44 (85.0%) completed the trial. Clinical deterioration occurred in 2 of 26 patients in each group (P >0.99). There were no serious adverse events in either group. Clinical deterioration occurred in 15 (6.0%) of 271 patients admitted to the CTC, and all of them were transferred to a hospital. In multivariate analysis, age between 55 and 64, fever and pneumonia at admission were independent risk factors for clinical deterioration. CONCLUSION: In this study of adult patients with symptomatic COVID-19 who were admitted to the CTC, there was no significant differences in clinical deterioration between patients treated with fluvoxamine and placebo (ClinicalTrials.gov Identifier: NCT04711863).

Radiologically Suspected Organizing Pneumonia in a Patient Recovering from COVID-19: A Case Report.

We report a case of coronavirus disease 2019 (COVID-19)-associated radiologically suspected organizing pneumonia with repeated negative Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) polymerase chain reaction (PCR) results from nasopharyngeal swab and sputum samples, but positive result from bronchoalveolar lavage fluid. Performing SARS-CoV-2 RT-PCR in upper respiratory tract samples only could fail to detect COVID-19-associated pneumonia, and SARS-CoV-2 could be an etiology of radiologically suspected organizing pneumonia.

The First Case of Multisystem Inflammatory Syndrome in Adult after COVID-19 in Korea.

Multisystem inflammatory disease in children is a Kawasaki disease like illness occurring after severe acute respiratory syndrome coronavirus 2 infection in children. As the pandemic progresses, similar syndromes were also reported in adult with a decreased incidence. Multisystem inflammatory syndrome in adults (MIS-A) can be characterized with shock, heart failure, and gastrointestinal symptoms with elevated inflammatory markers after coronavirus disease 2019 (COVID-19) infection. Herein, we describe the first case of MIS-A in South Korea. A 38-year-old man presented to our hospital with a 5-day history of abdominal pain and fever. He had been treated with antibiotics for 5 days at the previous hospital, but symptoms had worsened and he had developed orthopnea on the day of presentation. He suffered COVID-19 six weeks ago. Laboratory data revealed elevated white blood cell counts with neutrophil dominance, C-reactive protein, and B-type natriuretic peptide. Chest X-ray showed normal lung parenchyme and echocardiography showed severe biventricular failure with normal chamber size. We diagnosed him as MIS-A and treated with intravenous immunoglobulin and steroid.