ABSTRACT
OBJECTIVE: To investigate the relationship between viral load and secondary transmission in novel coronavirus disease 2019 (COVID-19). METHODS: Epidemiological and clinical data were obtained from immunocompetent laboratory-confirmed patients with COVID-19 who were admitted to and/or from whom viral loads were measured at Toyama University Hospital. Using a case-control approach, index patients who transmitted the disease to at least one other patient were analysed as "cases" (index patients) compared with patients who were not the cause of secondary transmission (non-index patients, analysed as "controls"). The viral load time courses were assessed between the index and non-index symptomatic patients using non-linear regression employing a standard one-phase decay model. RESULTS: In total, 28 patients were included in the analysis. Median viral load at the initial sample collection was significantly higher in symptomatic than in asymptomatic patients and in adults than in children. Among symptomatic patients (n = 18), non-linear regression models showed that the estimated viral load at onset was higher in the index than in the non-index patients (median [95% confidence interval]: 6.6 [5.2-8.2] vs. 3.1 [1.5-4.8] log copies/µL, respectively). In adult (symptomatic and asymptomatic) patients (n = 21), median viral load at the initial sample collection was significantly higher in the index than in the non-index patients (p = 0.015, 3.3 vs. 1.8 log copies/µL, respectively). CONCLUSIONS: High nasopharyngeal viral loads around onset may contribute to secondary transmission of COVID-19. Viral load may help provide a better understanding of why transmission is observed in some instances, but not in others, especially among household contacts.
Subject(s)
COVID-19 , Models, Biological , Nasopharynx , SARS-CoV-2/metabolism , Viral Load , Adolescent , Adult , Aged , COVID-19/metabolism , COVID-19/transmission , Case-Control Studies , Child , Child, Preschool , Female , Humans , Infant , Infant, Newborn , Male , Middle Aged , Nasopharynx/metabolism , Nasopharynx/virologyABSTRACT
Most patients with coronavirus disease 2019 (COVID-19) have just only mild symptoms, but about 5% are very severe. Although extracorporeal membranous oxygenation (ECMO) is sometimes used in critically patients with COVID-19, ECMO is only an adjunct, not the main treatment. If the patient's condition deteriorates and it is determined to be irreversible, it is necessary to decide to stop ECMO. A 54-year-old man was admitted on day 6 of onset with a chief complaint of high fever and cough. Computed tomography (CT) showed a ground glass opacity in both lungs, and reverse transcription-polymerase chain reaction (RT-PCR) diagnosed COVID-19. He was admitted to the hospital and started to receive oxygen and favipiravir. After that, his respiratory condition deteriorated, and he was intubated and ventilated on day 9 of onset, and ECMO was introduced on day 12. Two days after the introduction of ECMO, C-reactive protein (CRP) increased, chest X-p showed no improvement in pneumonia, and PaO2/FiO2 decreased again. As D-dimer rose and found a blood clot in the ECMO circuit, we had to decide whether to replace the circuit and continue with ECMO or stop ECMO. At this time, the viral load by RT-PCR was drastically reduced to about 1/1750. We decided to continue ECMO therapy and replaced the circuit. The patient's respiratory status subsequently improved and ECMO was stopped on day 21 of onset. In conclusion, viral load measurement by RT-PCR may be one of the indicators for promoting the treatment of severe COVID-19 patients.