A team of U.S. scientists has recently assessed the risk of severe respiratory disease coronavirus syndrome 2 (SARS-CoV-2) among passengers present inside an aircraft cabin. The results show that the risk of viral transmission of air during long flights is minimal. The study is currently available on the medRxiv * preprint server.
Background
Since its inception in December 2019, SARS-CoV-2, the causative pathogen of coronavirus 2019 (COVID-19), has caught more than 92.68 million people and has claimed more than 1.98 million lives worldwide. world. To contain the release of SARS-CoV-2, a number of control measures, such as regional or national locks, restriction of movement or travel, and physical speed, etc., were partially implemented by most government agencies. of countries. As a result, many countries have suffered severe socio-economic disasters. In the final stages of the pandemic, control measures were taken to support the economy and overcome the crisis.
Following lifts in travel restrictions, air services have resumed in many countries, raising the question of the risk of viral transmission during travel. Due to the potential transmission of SARS-CoV-2 in the air, the risk of infection is expected to be higher in enclosed or poorly ventilated areas. Therefore, it is believed that passengers or airline employees who are present inside an aircraft cabin for a long time may be at greater risk for SARS-CoV-2 infection.
Routine study design
In this study, the scientists have tried to quantify the risk of SARS-CoV-2 infection among passengers traveling through two large aircraft (Boeing 767 and 777 airframes). They have used fluorescent and DNA-tagged microspheres to study the dispersion and deposition of aerosol particles released from a simulated SARS-CoV-2 carrier. In particular, they have measured the level of aerosolas within the breathing zone of co-passengers seated in the same row with the simulated passenger or in rows in front or behind the store. They met these dimensions at various locations inside the aircraft, as well as placing the simulated passenger in several locations.
Important comments
Boeing 777
By measuring the percentage of grain dropping into the breathing zones, the scientists found that the largest dispersion occurs in a chair next to the infected simulated passenger. Seats placed in front of the store have been found to have a lower exposure rate, but seats behind the store have a higher exposure rate.
On further analysis, they have observed that the mixing of pollutants within a series occurs rapidly and that the flow of pollutants is directed toward the side of the aircraft where the valve is outflowed. In segments of the first level where there are gaps between wide seats, the level of exposure is found to be lower than in the economy sector.
Boeing 767
According to the findings, exposure risk in Boeing 767 is lower than Boeing 777. However, the same aircraft shares similar features of exposure risk. The flow of pollutants towards the aircraft is not lower in Boeing 767. The flow of pollutants emitted from the aft seat is directed towards the aft, but monitoring forward flow for contaminants released from the center front seat.
Performing similar experiments using a symbolic infectious source with or without a mask, approximately 15% reduction in the count of the numbers was observed in experiments performed with a mask.
Investigate meaning
The findings of the study suggest that there may be a limited risk of exposure to aerosols containing SARS-CoV-2 inside an aircraft due to rapid mixing, dilution and removal. A lower level of aerosol is observed in the farthest region of the aircraft, which indicates a lower risk for exposure. However, it is important to consider that the findings of the study are based on the simulation of a single source of infection, and therefore, the dynamics of transmission may vary in situations with multiple infectious carriers. In addition, the study focuses on aerosols and small granular material 1–3 µm. Transmission dynamics of large respiratory droplets were not included in the study.
* Important message
medRxiv publish preliminary scientific reports that are not peer-reviewed and, therefore, should not be seen as final, guiding health-related clinical practice / behavior, or be treated as information established.