Post Reply - On M-pox

Bruno Hernaez and colleagues reported that in their study of 44 patients with symptomatic mpox at two health centres in Spain, high loads of MPXV DNA were identified in 35 (85%) of 41 saliva samples and that infectious MPXV was recovered from 22 (67%) of 33 saliva samples positive for MPXV DNA. The reported maximum viral load in saliva samples of patients reached approximately 1×10 copies of viral genome per mL, and the minimum size of respiratory particles carrying the virus in those viral load conditions was calculated to be more than 25 μm, by use of aerosol dynamics theories and the reported viral load (appendix).,  ,  ,  

Hugh Adler and colleagues reported on the viral loads (denoted by Ct values) of MPXV identified in the upper respiratory tracts of seven patients in the UK. The viral loads of the patients, based on these Ct values, were estimated to be less than 106 copies per mL.,   The minimum size of respiratory particles carrying MPXV virions was estimated to be more than 100 μm using aerosol dynamics theories and the aforementioned viral loads.,  ,  ,  ,  

If respiratory particles (ie, particles emitted from respiratory tracts) are larger than the cutoff size between aerosols and droplets, they are categorised as droplets (ie, large earthbound respiratory particles), whereas if they are smaller than the cutoff size, they are catagorised as aerosol particles (ie, tiny airborne particles; appendix). The cutoff size between aerosols and droplets is highly dependent on the surrounding airflow conditions, including relative humidity and airflow velocity. The standard cutoff size between aerosols and droplets, which has been under debate in aerosol dynamics, ranges between 5 μm and 100 μm.,  ,