Transmission of SARS-CoV-2 on aircraft: A scoping review

IntroductionThe assessment of empirical epidemiological data is needed to assess the transmissibility of SARS-CoV-2 in aircraft settings. This review summarises reported contact- tracing data and evaluates the secondary attack rates (SAR) and factors associated with SARS- CoV-2 transmission in aircraft, to provide insight for future decision making in the context of future respiratory pandemics. MethodsThis scoping literature review assessed studies published between December 2020 to November 2023 in Ovid Medline, Embase and Cochrane Library databases. The inclusion criteria were based on the PCC framework (P-Population, C-Concept, C-Context). The study population was restricted to passengers and crew (population) to assess transmission (concept) in an aircraft setting (context). ResultsThirty-one studies which assess SARS-CoV-2 transmission in 521 domestic and international flights were included in this systematic review. The SAR reported in the studies with an identified index case ranged from 0% to 16%. Significant variation in the reporting across studies was noted. Overall, the studies reported that using face masks or respirators by passengers and crew members during flight seemed to be a possible strategy for mitigating SARS-CoV-2 transmission while sitting within close proximity to index cases ([≤]2 seats in every direction) was associated with a higher SAR. ConclusionsOur results are consistent with sporadic clusters happening onboard aircraft. Close proximity to COVID-19 cases within the aircraft was associated with a higher SAR. Our findings further underscore the need for a systematic approach to examining and reporting SARS-CoV-2 transmission onboard aircraft. This evidence may assist policymakers and transportation authorities in the development of emergency preparedness measures and travel guidance during the post-pandemic COVID-19 era.