Dietary intervention with functional foods modulating gut microbiota for improving the efficacy of COVID-19 vaccines.

Dysbiosis of the gut microbiota with aging contributes to a reduction in important cross-feeding bacterial reactions in the gut and immunosenescence, which could contribute to a decrease in vaccine efficacy. Fever, cough, and fatigue are the main signs of coronavirus disease 2019 (COVID-19); however, some patients with COVID-19 present with gastrointestinal symptoms. COVID-19 vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is one of the best measures to reduce SARS-CoV-2 infection rates and the severity of COVID-19. The immunogenicity of COVID-19 vaccines is influenced by the composition of the gut microbiota, and the immune response to COVID-19 vaccines decreases with age. In this review, we discuss gut microbiota dysbiosis and immunosenescence in the older adults, the role of gut microbiota in improving the efficacy of COVID-19 vaccines, and dietary interventions to improve the efficacy of COVID-19 vaccines in the older adults.

Reduction in COVID-19 Vaccine Effectiveness against SARS-CoV-2 Variants in Seoul according to Age, Sex, and Symptoms: A Test-Negative Case-Control Study.

BACKGROUND: We evaluated vaccine effectiveness (VE) against infections with SARS-CoV-2 variants of concern in Seoul, the capital of the Republic of Korea, having the highest population density in the country, under real-world conditions. METHODS: We evaluated the reduction in the effectiveness of mRNA and viral-vector COVID-19 vaccines against infection by the SARS-CoV-2 delta variant in a subpopulation from April 2021 to July 2021 who visited screening clinics in Seoul using a test-negative case-control study design. Moreover, we conducted a case-control study matching the ten-year-old age group, sex, healthcare workers, and five districts of Seoul, which are considered confounding factors. RESULTS: The full VE in the pre-delta-dominant period was 95.0% (95% confidence interval [CI]: 91.2-97.2); however, it decreased to 61.1% (95% CI: 53.2-67.6) during the delta-dominant period. Notably, we found that COVID-19 VE was significantly decreased in individuals aged ≥80 years (52.9%, 95% CI: -9.9-79.8), men (50.6 %, 95% CI: 39.4-59.8), and asymptomatic individuals (49.8%, 95% CI: 36.5-60.3) during the widespread SARS-CoV-2 delta variant circulation. CONCLUSIONS: Vaccine-mediated protection drastically declined during the delta-dominant period and in vulnerable groups. This study suggests the requirement for additional countermeasures, such as the administration of a booster vaccine, in vulnerable groups based on age, sex, and symptomatic manifestation.

Diagnostic Laboratory Characteristics of COVID-19 Patients Infected by Fomites: COVID-19 Outbreak in a South Korean Public Administrative Facility.

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.

Evaluation of Intervention Policies for the COVID-19 Epidemic in the Seoul/Gyeonggi Region through a Model Simulation.

PURPOSE: To evaluate the efficacy of intervention policies on coronavirus disease-19 (COVID-19) dissemination. MATERIALS AND METHODS: An age-structured compartmental model for the COVID-19 outbreak was proposed to predict the impact of control measures in the Seoul/Gyeonggi region. The model was calibrated based on actual data and realistic situations, including daily vaccine doses, proportion of delta variant cases, and confirmed cases by age. We simulated different scenarios for non-pharmaceutical interventions by varying social distancing and school attendance strategies. RESULTS: Two-step mitigation of social distancing without in-person classes would result in a rapid increase in confirmed cases up to 10000 but would keep severe cases within the manageable range of the health care system. The overall impact of taking down the distancing level by one step with twice the increase in contacts at school was comparable to the above scenario. Implementation of two-step mitigation of social distancing along with a two-fold increase in contacts among the school-age group would dramatically increase confirmed and severe cases by over 80000 and 100, respectively, as early as the beginning of December. This policy would cause the situation to spiral out of control, considering the scale of the response and time to prepare. On the other hand, the burden on the current healthcare system caused by two-step mitigation of social distancing and 40% increased contacts in the school-age group was manageable if prepared. CONCLUSION: A compromise between social distancing and school attendance policy and timely preparations for the spread of COVID-19 are required.

Clinical Course and Outcomes of 3,060 Patients with Coronavirus Disease 2019 in Korea, January-May 2020.

BACKGROUND: The fatality rate of patients with coronavirus disease 2019 (COVID-19) varies among countries owing to demographics, patient comorbidities, surge capacity of healthcare systems, and the quality of medical care. We assessed the clinical outcomes of patients with COVID-19 during the first wave of the epidemic in Korea. METHODS: Using a modified World Health Organization clinical record form, we obtained clinical data for 3,060 patients with COVID-19 treated at 55 hospitals in Korea. Disease severity scores were defined as: 1) no limitation of daily activities; 2) limitation of daily activities but no need for supplemental oxygen; 3) supplemental oxygen via nasal cannula; 4) supplemental oxygen via facial mask; 5) non-invasive mechanical ventilation; 6) invasive mechanical ventilation; 7) multi-organ failure or extracorporeal membrane oxygenation therapy; and 8) death. Recovery was defined as a severity score of 1 or 2, or discharge and release from isolation. RESULTS: The median age of the patients was 43 years of age; 43.6% were male. The median time from illness onset to admission was 5 days. Of the patients with a disease severity score of 3-4 on admission, 65 (71.5%) of the 91 patients recovered, and 7 (7.7%) died due to illness by day 28. Of the patients with disease severity scores of 5-7, 7 (19.5%) of the 36 patients recovered, and 8 (22.2%) died due to illness by day 28. None of the 1,324 patients who were < 50 years of age died; in contrast, the fatality rate due to illness by day 28 was 0.5% (2/375), 0.9% (2/215), 5.8% (6/104), and 14.0% (7/50) for the patients aged 50-59, 60-69, 70-79, and ≥ 80 years of age, respectively. CONCLUSION: In Korea, almost all patients of < 50 years of age with COVID-19 recovered without supplemental oxygen. In patients of ≥ 50 years of age, the fatality rate increased with age, reaching 14% in patients of ≥ 80 years of age.