Nearly 56 cases have been traced to a Starbucks outlet in the city of Paju in South Korea.
Arirang News reported that many patrons at Starbucks were not wearing face masks, and the poorly-ventilated space had likely contributed to the spread of COVID-19.
However, the employees at the store were not infected by the coronavirus, and health expert like Choi Won-suk — an infectious disease professor from Korea University Ansan Hospital — believed that it was because of the usage of face masks.
The health officials revealed that the outbreak of this particular cluster was originated from an infected person sitting in the cafe next to the air conditioner. The air conditioning system helped disperse contagious aerosol particles across the enclosed space, contaminating the air and common surfaces as well.
Yonhap News Agency reported the Korea Centres for Disease Control and Prevention (KCDC) chief Jeong Eun-kyeong as saying that the patrons did not wear masks in the store and that the humid summer weather had also contributed to the poor air ventilation.
“Many of the visitors didn’t wear masks, and there seems to be no proper air ventilation at the store even though air conditioners were in operation due to humid weather.”
Emphasising that COVID-19 transmission may not necessarily occur via aerosol transmission, Jeong suggested that droplet transmission was indeed possible in the confined space. The coronavirus can also spread via direct contact by touching common surfaces like tables, chairs and doorknobs.
“Even if infections did not occur via aerosol transmission, droplet transmission is also possible in a confined space, and the virus could have spread via hand contact.”
In regards to this particular Starbucks case, four employees who were on duty were not infected.
Choi cautioned that people should refrain from touching surfaces in between taking off and putting on face masks as it would contaminate the masks and potentially infecting the individual.
Apart from that, it was advised that buildings should keep their windows and doors open to ventilate the air. People were also warned to avoid having meals or drinks indoors.
Instead, they were advised to take their food and drinks home or to other private places.
Despite acknowledging face masks that have better filters would be more effective in preventing infection, however, wearing a mask regardless of the type is “the best protection” as reported by Arirang News.