Transmission of SARS‐CoV‐2 during a 2‐h domestic flight to Okinawa, Japan, March 2020

Abstract

Background Coronavirus disease (COVID‐19), caused by severe acute respiratory syndrome coronavirus (SARS‐CoV‐2), has rapidly spread globally. Potentially infected individuals travel on commercial aircraft. Thus, this study aimed to investigate and test the association between the use of face masks, physical distance, and COVID‐19 among passengers and flight attendants exposed to a COVID‐19 passenger in a domestic flight. Methods This observational study investigated passengers and flight attendants exposed to COVID‐19 on March 23, 2020, on board a flight to Naha City, Japan. Secondary attack rates were calculated. Whole‐genome sequencing of SARS‐CoV‐2 was used to identify the infectious linkage between confirmed cases in this clustering. The association between confirmed COVID‐19 and proximity of passengers' seats to the index case and/or the use of face masks was estimated using logistic regression. Results Fourteen confirmed and six probable cases were identified among passengers and flight attendants. The secondary attack rate was 9.7%. Twelve of 14 SARS‐CoV‐2 genome sequences in confirmed cases were identical to that of the index case or showed only one nucleotide mutation. Risk factors for infection included not using a face mask (adjusted odds ratio [aOR]: 7.29, 95% confidence interval [95% CI]: 1.86‐28.6), partial face mask use (aOR: 3.0, 95% CI: 0.83‐10.8), and being seated within two rows from the index patient (aOR: 7.47, 95% CI: 2.06‐27.2). Conclusion SARS‐CoV‐2 was transmitted on the airplane. Nonuse of face masks was identified as an independent risk factor for contracting COVID‐19 on the airplane.

Increased airborne transmission of COVID-19 with new variants, Implications for health policies

“…These equations funded on the well mixed room hypothesis are the basis of the famous Wells-Riley model and are convenient for a very large number of indoor situations. However, inhomogeneous infection patterns are reported for a number of well-documented transmission events in closed spaces, especially in restaurants [14-16] but also in other places such as aircrafts [17]. Generally, in these specific well studied cases, inhomogeneity was created by the mechanical ventilation system of air conditioning (hereafter AC) with recirculation, inducing locally larger air velocity.…”

The emission and dynamics of droplets from human expiratory activities and COVID-19 transmission in public transport system: A review

“…Table 6 lists the 22 studies on COVID-19 transmission and/or prevalence on airplanes. Among them, 13 studies reported in-flight transmission rates ranging from 0% to 10% with a median of 0.36% [ 7 , 12 , [77] , [78] , [79] , [80] , [81] , [82] , [83] , [84] , [85] , [86] , [87] ]. The highest transmission rate of 10% was reported on a domestic flight in Japan where 14 passengers were infected [ 87 ].…”

Recent progress on studies of airborne infectious disease transmission, air quality, and thermal comfort in the airliner cabin air environment

“…They concluded that there was potential COVID‐19 transmission in airplane cabins. Toyokawa et al 5 studied passengers and flight attendants exposed to COVID‐19 during a flight on March 23, 2020. By using whole‐genome sequencing of SARS‐CoV‐2 to identify the infectious linkage, they found a secondary attack rate of 9.7%.…”

“…A study by Boeing 3 showed that the global risk of COVID‐19 transmission during air travel was 1 in 1.7 million. However, other studies have reported an attack rate of 9.7% to 62% 4,5 . The flying public has reasonable doubts about the ability of modern airliners to protect them from infection by airborne diseases such as COVID‐19.…”

“…However, other studies have reported an attack rate of 9.7% to 62%. 4,5 The flying public has reasonable doubts about the ability of modern airliners to protect them from infection by airborne diseases such as COVID-19. Airborne infectious diseases are not the only source of concern for the flying public.…”