Outbreak Transmission is possible over long distances
In a joint study by the German Helmholtz Centre for Infection Research (HZI), the University Medical Centre Hamburg-Eppendorf (UKE) and the Heinrich-Pette-Institute, Leibniz Institute for Experimental Virology (HPI), the origins of the first SARS CoV-2 outbreak in May 2020 at Tönnies in Rheda-Wiedenbrück, the largest meat processing complex in Germany, were investigated. The study results have now been published on the preprint platform SSRN. A publication in a specialist journal with peer review procedure will follow.
The results reconstruct initial transmission events in May 2020: Starting with a single employee, the virus was transmitted to several people within a radius of more than 8 m. The main transmission took place in the cutting area for beef quarters, where the air is circulated and cooled to 10 °C. In contrast, the housing situation of the workers did not play a significant role during the investigated phase of the outbreak.
Furthermore, an evaluation of the virus sequences shows that all SARS-CoV-2-positive individuals from the infection cluster in May 2020 share a new combination of eight mutations that had not been observed before.
"Our results indicate that the conditions of the cutting plant - i.e. low temperature, low fresh air supply and constant air circulation through the air conditioning system in the hall, together with strenuous physical work - promoted the aerosol transmission of SARS-CoV-2 particles over greater distances," says Prof. Adam Grundhoff, co-author of the study and research group leader at HPI, "It is very likely that these factors in general play a decisive role in the worldwide outbreaks in meat or fish processing plants.“