ABSTRACT
The COVID-19 pandemic has brought an unprecedented crisis to the global health sector. When discharging COVID-19 patients in accordance with throat or nasal swab protocols using RT-PCR, the potential risk of reintroducing the infection source to humans and the environment must be resolved. Here, 14 patients including 10 COVID-19 subjects were recruited; exhaled breath condensate (EBC), air samples and surface swabs were collected and analyzed for SARS-CoV-2 using reverse transcription-polymerase chain reaction (RT-PCR) in four hospitals with applied natural ventilation and disinfection practices in Wuhan. Here we discovered that 22.2% of COVID-19 patients (n = 9), who were ready for hospital discharge based on current guidelines, had SARS-CoV-2 in their exhaled breath (~105 RNA copies/m3). Although fewer surface swabs (3.1%, n = 318) tested positive, medical equipment such as face shield frequently contacted/used by healthcare workers and the work shift floor were contaminated by SARS-CoV-2 (3-8 viruses/cm2). Three of the air samples (n = 44) including those collected using a robot-assisted sampler were detected positive by a digital PCR with a concentration level of 9-219 viruses/m3. RT-PCR diagnosis using throat swab specimens had a failure rate of more than 22% in safely discharging COVID-19 patients who were otherwise still exhaling the SARS-CoV-2 by a rate of estimated ~1400 RNA copies per minute into the air. Direct surface contact might not represent a major transmission route, and lower positive rate of air sample (6.8%) was likely due to natural ventilation (1.6-3.3 m/s) and regular disinfection practices. While there is a critical need for strengthening hospital discharge standards in preventing re-emergence of COVID-19 spread, use of breath sample as a supplement specimen could further guard the hospital discharge to ensure the safety of the public and minimize the pandemic re-emergence risk.
ABSTRACT
AIM: In 9-17-year-old Chinese girls, the AS04-adjuvanted HPV-16/18 vaccine (AS04-HPV-16/18) given as three-dose schedule induced high antibody levels, which were noninferior 1 month after the third dose to those observed in 18-25-year-old Chinese women in a large efficacy study. We assessed the persistence of antibodies 8-9 years after vaccination in the same subjects. METHODS: This follow-up phase III, open-label study (NCT03355820) included subjects who had received three doses of AS04-HPV-16/18 in the initial trial (NCT00996125). Serum antibody concentrations were assessed by ELISA and compared to antibody persistence observed in 18-25-year-old Chinese women 6 years after first vaccination in the efficacy study (NCT00779766). RESULTS: Out of the 227 enrolled subjects, 223 were included in the per-protocol immunogenicity analysis. Mean interval from first AS04-HPV-16/18 dose to blood sampling was 101.4 months (8.5 years). For antibodies against HPV-16 and -18, 8.5 years after first vaccine dose all subjects remained seropositive and antibody. Geometric mean concentrations (GMCs) were 1236.3 (95% confidence interval [CI]: 1121.8; 1362.4) and 535.6 (95% CI: 478.6; 599.4) ELISA Units/mL, respectively. These seropositivity rates and antibody GMCs were higher than those observed 6 years after first vaccination of 18-25-year-old women. CONCLUSION: Sustained anti-HPV-16 and -18 immune responses were observed 8-9 years after AS04-HPV-16/18 vaccination of 9-17 year-old Chinese girls that were higher than the ones observed 6 years after first vaccination in Chinese adult women in whom AS04-HPV-16/18 efficacy against cervical intraepithelial neoplasia of grade ≥2 was demonstrated.
