Result of SARS-CoV-2 nucleic acid test for aerosol in a designated COVID-19 hospital

ABSTRACT

OBJECTIVE: To collect aerosol from isolation wards of a designated COVID-19 hospital and conduct the nucleic acid test so as to provide scientific basis for prevention and control of COVID-19. METHODS: The air aerosol specimens were collected from layout sites in the isolation wards of the hospital by using bioaerosol collector, and the COVID-19 nucleic acid test was carried out for all of the specimens by using fluorescent polymerase chain reaction(PCR) and digital PCR. RESULTS: A total of 86 aerosol samples were collected, all of which were tested negative for the fluorescent PCR, the result of the digital PCR test showed that 14 air aerosol samples were tested positive for COVID-19 nucleic acid, with the detection rate 16.28%. The toilets of the patients and taking-off area of protective supplies of healthcare workers were the major places where the specimens were tested positive. The positive rate of nucleic acid test was significantly higher in in intensive care units than in common wards, however, there was no significant difference in the positive rate of nucleic acid among the aerosol specimens in different wards(?-2=7.871, P=0.248);there was no significant difference in the positive rate of nucleic acid of aerosol between the patients with CT value more than 30 and the patients with CT value no more than 30(?-2=0.232, P=0.630). CONCLUSION: There are still viral nucleic acids in the air aerosol of the isolation wards during the middle and late disease course of the COVID-19 patients, but the copy number of novel coronavirus is not large in the specimens. The detection rate of the viral nucleic acid is high in the aerosol of the wards that are crowed and poorly ventilated and are associated with the cases. It is necessary for the health care workers to take good care of themselves, keep the environment well ventilated and do a good job in environmental cleaning and disinfection and air purification.