Table 3. The five most frequently reported occupations or jobs with mass outbreaks# of COVID-19 by country as of July 31, 2021.

Country	The five most frequent occupations/workplaces with mass outbreaksa	Major risk factors for causing mass outbreaksb
India	Wholesale market	Lack of awareness
	Religious sites	Overcrowding
	Slums	Lack of use of PPE
	Wholesale market vendors	Poor hygiene practice
		Non-compliance with regulations
Indonesia	Military school	Information not available
	Health care workers	Exposure to infected patients Overcrowding Group cycling activities
	Cigarette factory	Exposure to infected workers Lack of PPE
	Electronics factory	Exposure to infected workers Lack of ventilation
	Offices (government offices, offices in high-rise buildings, etc.)	Overcrowding, insufficient ventilation Poor indoor air quality
	Garment	Exposure to infected workers Poor indoor air quality
Japanc	Health care workers (licensed 5,749)	Exposure to infected patients/poor infection control
	Social insurance, social welfare, and care services such as childcare professionals (unlicensed) (321)	Poor infection control
	Health care industry (unlicensed) (238)	Exposure to infected patients/poor infection control
	Transport and postal activities such as bus, taxi, or truck drivers (216)	Poor infection control
	Industries unable to be classified (147)	Poor infection control
Malaysia	A factory with migrant workers making gloves	Migrant workers living in dense shared quarters
	Vehicle workshops	Overcrowding of work premises – inadequate physical distancing
	Construction	Non-compliance with government SOP
	Public institutions, including hospitals (health care workers)	Poor ventilation
	Supermarkets	Close proximity
New Zealand11)	NZ does not break down cases by occupation, but by clusters	Mainly overseas links and social gatherings outside of work
Republic of Korea12)	Health care workers	Exposure to infected patients/lack of PPE/poor infection control
	Workplaces with migrant workers	-
	Call center	Lack of PPE/lack of ventilation/dense working area/poor infection control
	Retailer: logistics	Share PPE/lack of ventilation/dense working area/poor infection control
	Detention center	Lack of PPE/lack of ventilation/dense facility/poor infection control
	Food and dining facility/religious facility/army.	Lack of ventilation/frequent contact/poor infection control
	Others	-
Republic of Philippines	Health care workers and police/military personnel	Client interaction
	Public/company transport facilities, manufacturing/production areas, canteens while eating, lounges/rest areas	Areas where workers converge
	Designated smoking areas	Non-use of PPE
Taiwan	Workplaces with migrant workers	Exposure from original countries/poor infection control of workers
	Health care workers	Exposure to infected patients/lack of PPE/poor infection control
	Pilots	Exposure from flied countries/dense working area/poor infection control
	Entertainment sites	Dense facility/Poor infection control
	Quarantine hotel workers	Exposure to infected patients/dense working area/poor infection control
Thailand	Construction worker camps	Unaware of COVID-19, No PPE
	Cold storage factory	Migrant workers in the community. Crowded places, which are high-risk areas, Lack of PPE
	Shoe factory	Poor infection control, Lack of PPE
	Workplaces with migrant workers	Migrant workers in the community. Crowded places, which are high-risk areas, Lack of PPE
	Entertainment site	Poor infection control, Lack of PPE

Abbreviation : PPE, personal protective equipment.

^aThe ranking of clusters was qualitatively determined by the authors based on either news media or official reports by the health authority.

^bListed qualitatively by the authors in each country and summarized by country.

^cReleased by the Japanese government as of July 31, 2021.