key: cord-0998459-12p1jha1 authors: Mun, Eunchan; Kim, Young-Man; Han, Boksoon; Jeong, Jinsook; Kim, Wonsool; Lee, Changhwan title: A case series of flight attendants at risk of COVID-19 in South Korea in 2020 date: 2021-01-22 journal: Ann Occup Environ Med DOI: 10.35371/aoem.2021.33.e1 sha: f3477676ca659dcbab07fa8c04a99575f5b63a2e doc_id: 998459 cord_uid: 12p1jha1 BACKGROUND: Coronavirus disease 2019 (COVID-19) has infected many individuals worldwide. Individuals in contact with unspecified people during their work, may be at risk of occupational exposure. On June 22, 2020, 1,435 overseas patients were identified in the Republic of Korea. Considering the influx of overseas patients, aircraft-mediated COVID-19 transmission is a major concern. CASE PRESENTATION: We presented two flight attendants diagnosed with COVID-19 who shared the crew's resting area and ground transportation, and discussed the risks experienced by flight attendants. CONCLUSIONS: Biosafety guidelines for cabin crews should be intensified, and their COVID-19 risks must be further investigated. Policymakers must consider comprehensive surveillance systems for workers with high risks of occupational exposures and transmissions, such as flight attendants. HEPA: high-efficiency particulate air; IATA: International Air Transport Association; ROK: Republic of Korea. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. The authors declare that they have no competing interests. public welfare. We examined two flight attendants infected with COVID-19 using public information, and discussed their risks for COVID-19. A 25-year-old woman working for Korean Air as a cabin crew member became ill on February 21, 2020, with symptoms of cough and a mild fever. She was examined for COVID-19 on February 24, 2020 and was confirmed positive the next day ( Table 1) . A 36-year-old woman who worked on the same flights (KE012 and KE017) showed symptoms including coughs, a mild fever, and myalgia on March 6, 2020. She was diagnosed with COVID-19 on the same day ( Table 1) . After the first flight attendant was diagnosed with COVID-19, a 2-week self-quarantine period was imposed on all crew members, including the second flight attendant. Of the 30 crew members, only she was diagnosed with COVID-19 on the eleventh day of quarantine. She did not have any known epidemiological links to COVID-19, other than contact with the first flight attendant. During both flights (KE012 and KE017, A380), the second flight attendant worked on the upper deck (prestige class), and the first flight attendant worked on the main deck (first and economy class) ( Table 2) . They shared the crew's resting area and ground transportation after the first flight attendant had developed symptoms. Korean Air shut down its Incheon Operation Center on February 25, 2020 and disinfected the aircrafts. All 30 crew members entered self-quarantine for 2 weeks, which was later extended by an additional week after the second flight attendant was diagnosed with COVID-19 (Fig. 1 ). The study was approved by the Institutional Review Board of Kangbuk Samsung Hospital (KBSMC 2020-06-044), which exempted the requirement of informed consent owing to the use of public information. Occupationally, flight attendants contact many unspecified individuals and visit countless locations. Contacts may be encountered during the flights or on the ground before and after flights, including at airline operation centers, airports, accommodations, transportations, and local stopover areas. In the aircrafts, flight attendants encounter random passengers in cabins and may be in close contact with other flight attendants, especially in the galleys and the crew's resting areas. Therefore, they can contract COVID-19 by inter-transmission (via external environments), as in case A; or intra-transmission (among themselves), as in case B. In particular, the aircraft cabins, where flight attendants contact random individuals and their belongings, as well as stopover sites and the crew's resting areas, where flight attendants relax and are unsupervised, pose the highest exposure risks. Generally, cabin air quality has a high purity level because the recirculated air passes through high-efficiency particulate air (HEPA) filters. The International Air Transport Association (IATA) considers the risk of COVID-19 transmission among passengers to be very low for several reasons: 1) passengers are seated facing forward and not toward each other, 2) the back of seats serve as a physical barrier, 3) passenger movements are limited onboard, and 4) the direction of air flow is from the ceiling to the floor [3] . However, this risk assessment neglects the possibility of transmission via contaminated surfaces and also underestimates people's onboard activities. The cases of in-flight transmission of COVID-19 between passengers and crew members have recently been reported [4] . The Centers for Disease Control and Prevention (CDC) and Federal Aviation Administration (FAA) recommend that crew members with known exposure to COVID-19 do not work for 14 days, even if they have no symptoms. Besides the risk of in-flight transmission, transmission from the external environment may also be significant considering that flight attendants' activities extend beyond the cabin environment. The CDC and FAA recommend providing crew members with private ground transportations for travelling back and forth hotels near the airport, and that their rooms are sanitized in advance of the crew's arrival. However, current guidance lacks surveillance for asymptomatic infections through uncertain or undetermined transmission routes [5] . Considering the substantial occupational risks of flight attendants, in addition to general risks that the public is exposed to, surveillance should not only rely on self-reports of symptoms or exposures to COVID-19. Authorities should consider mandatory COVID-19 testing of all flight attendants prior to take-off, regardless of symptoms or exposures to COVID-19. International air travel of travelers has been collapsing for several months during the COVID-19 pandemic. Recently, some nations and airlines are preparing to resume operations. As flight attendants repeatedly contact many unspecified individuals, their protection against COVID-19 risks is of utmost importance. By protecting the flight attendants, another COVID-19 wave may also be prevented. Biosafety guidelines for cabin crews should be intensified, and their COVID-19 risks must be further investigated. Policymakers must consider comprehensive surveillance systems for workers with high risks of occupational exposures and transmissions, such as flight attendants. World Health Organization. Coronavirus disease (COVID-19) pandemic International Air Transport Association. Biosafety for Air Transport. Biosafety for air transport: a roadmap for restarting aviation In-flight transmission of SARS-CoV-2 COVID-19: updated interim occupational health and safety guidance for air carriers and crews The authors would like to thank HJK, III, and EJN for advice on the occupational characteristics of flight attendants.