TY - JOUR AU - Thanasitthichai, Somchai AU - Thaiyakul, Arunee AU - สง่า, ณัฐธยา AU - Poovorawan, Yong AU - Kwanjaroensub, Suthaluk AU - Yingin, Patchariya PY - 2022/06/29 Y2 - 2024/03/28 TI - Viral Infectivity of Asymptomatic or Mild Symptomatic without Risk Factors COVID-19 Case-patients at 7 and 10 Days after Diagnosis JF - Journal of The Department of Medical Services JA - J DMS VL - 47 IS - 2 SE - Original Article DO - UR - https://he02.tci-thaijo.org/index.php/JDMS/article/view/256786 SP - 13-21 AB - <p><strong>Background: </strong>Asymptomatic and mild symptomatic patients with no risk of severe coronavirus disease (COVID-19) will be quarantine for 10 days as Thai guideline’s recommendation. If the quarantine period can be shortened from 10 to 7 days, we can save many resources.<strong> Objective:</strong> to assess the rate of SARS-CoV-2 (viral infectivity) in asymptomatic and mild symptomatic COVID-19 patients diagnosed on 7<sup>th</sup> day and 10<sup>th</sup> day after diagnosis.<strong> Method: </strong>This prospective descriptive study performed at the hospitel (Narai Hotel) under the supervision of Lerdsin Hospital from March to December 2021. 88 of subjects were recruited. Nasopharyngeal and throat secretion culture for SARS-CoV-2, subgenomic RNA and clotted blood for IgM and IgG using ELISA were collected. <strong>Results:</strong> We found 64.4% female, mean age 37.1 ± 12.3 years and BMI 23.1 ± 3.5 kg/m<sup>2</sup>. Asymptomatic and mild symptomatic subjects were 34.1% and 65.9% respectively. rRT-PCR on 7<sup>th</sup> day and 10<sup>th</sup> day showed “detected” result 82.9% (95% CI 75.1, 90.8) and 81.8% (95% CI 73.8, 89.9) respectively whereas, virus culture on 7<sup>th</sup> day were “not detected” 98.9% (95 CI 96.7, 100) and no virus was found on 10<sup>th</sup> day.&nbsp; Subgenomic RNA method showed alpha (B.1.1.7) 53.4%, delta 11.4%, and neither alpha nor delta strains 35.2%. Geometric mean titer (GMT) of anti-spike IgM on day 7 and day 10 were 2.42 (95%CI 1.77, 3.30) and 3.45 (95%CI 2.6, 4.6) respectively (<em>p</em> &lt; .001) while anti-RBD IgG were 209.2 and 520.1, respectively (<em>p</em> &lt; .0001). Moreover, IgM and IgG levels on 7<sup>th</sup> day, the seropositive rates were 79.6% and 77.3% while on 10<sup>th</sup> day, were 89.8% and 93.2% respectively. <strong>Conclusion:</strong> The infection on 7<sup>th</sup> days and 10<sup>th</sup> day from diagnostic date by RT-PCR showed a large number of infections, virus culture showed very rarely “detected” report on 7<sup>th</sup> day and “not detected” on 10<sup>th</sup> day after diagnosis.</p> ER -