Professor Neelika Malavige from the Department of Immunology and Molecular Sciences of the Sri Jayawardenepura University, tweeted saying large indoor gatherings should be stopped right now, until a large proportion of the adult population are fully vaccinated (2 weeks after 2nd dose).
She tweeted this in response to a study which revealed that fine aerosols produced by talking and singing contain more SARS-CoV-2 copies than coarse aerosols and may play a significant role in SARS-CoV-2 transmission.
The study published by the Oxford University noted that exposure to fine aerosols, especially indoors, should be mitigated. It noted that isolating viable SARS-CoV-2 from respiratory aerosol samples remains challenging, and whether this can be more easily accomplished for emerging SARS-CoV-2 variants is an urgent enquiry necessitating larger-scale studies.
Using a G-II exhaled breath collector, experts had measured viral RNA in coarse and fine respiratory aerosols emitted by COVID-19 patients during 30 minutes of breathing, 15 minutes of talking, and 15 minutes of singing.
Thirteen participants (59%) emitted detectable levels of SARS-CoV-2 RNA in respiratory aerosols, including 3 asymptomatic and 1 presymptomatic patient. Viral loads ranged from 63–5,821 N gene copies per expiratory activity per participant, with high person-to-person variation. Patients earlier in illness were more likely to emit detectable RNA. Two participants, sampled on day 3 of illness, accounted for 52% of the total viral load. Overall, 94% of SARS-CoV-2 RNA copies were emitted by talking and singing. Interestingly, 7 participants emitted more virus from talking than singing. Overall, fine aerosols constituted 85% of the viral load detected in the study. Virus cultures were negative. (Colombo Gazette)