Analysis of the factors that affect the detection duration of SARS-CoV-2 in Loop Mediated Isothermal Amplification among COVID-19 inpatients.

ABSTRACT

In COVID-19 patients who are severe or immunocompromised, the duration of infectious viral shedding may be longer, and a longer isolation duration is recommended. In National Sagamihara hospital, a decline in the viral load to end the isolation of COVID-19 hospitalized patients is confirmed by loop mediated isothermal amplification (LAMP). However, a subset of patients persisted in displaying LAMP positivity for more than 20 days since symptom onset. Therefore, we conducted a retrospective observational study to investigate factors impacting the persistence of LAMP positivity. The study included 102 participants. The severity of COVID-19 was mild in 25.5%, moderate in 67.6%, and severe in 6.9% of patients. The median number (interquartile range) of days until negative LAMP since symptom onset was 16 (14-19) days. Multivariate logistic regression analysis showed that age ≥55 years and the delta variant were correlated with persistently LAMP positive for more than 20 days since symptom onset. This study identified that age, the delta variant, and oxygen requirement were factors contributing to persistently positive LAMP. Therefore, it is posited that in these patients, the implementation of LAMP for de-isolation would result in a prolonged duration of isolation.