The dual-use of nasal strip in the surveillance of active and convalescent SARS-CoV-2 cases

Abstract

SARS-CoV-2 (SCoV-2) has caused worldwide pandemic for more than a year. Its transmission is yet under control as most infected people show mild flu-like illness or are asymptomatic. Respiratory samples screening for SCoV-2 nuclei acid is utilized to identify active cases while the serological detection of SCoV-2 specific immunoglobulin (Ig) represents exposure to SCoV-2. The nasal mucosa is the infection site and the nasal epithelial lining fluid (NELF) contains virus and reflects its immunological profile. We collected NELF using nasal strips from 82 SCoV-2 infected subjects on disease confirmation, day 7, 14, 21, 28, 3 and 6 months after. NELF was eluted (Chan, RWY et al. J Infect 2020) and subjected to viral gene quantification and anti-SCoV-2 IgA measurement by ELISA. The clinical lab data showed that the viral load lasted for 7.5day(d) in children and 9.3d in adult. 94% of patients who took the serological test showed positive IgG results on 12d (median) after diagnosis. 19 subjects were followed for >3 months for their SCoV-2 IgA level in NELF. The 1st detection was 5d (median) post-diagnosis, which is earlier than the serological IgG. NELF IgA lasted for 92d and peaked on 13d post-diagnosis with different magnitudes. Here, we demonstrated that collecting NELF by nasal strip as a self-administered and non-invasive tool for the surveillance of active and convalescent cases. J Infect doi: 10.1016/j.jinf.2020.11.009