Airport Alert: Harvard Issues "Curb to Curb" Report on Airport's Efforts to Mitigate COVID-19

February 11, 2021

Harvard's Aviation Public Health Initiative (APHI) today issued a comprehensive report on the risk of coronavirus transmission in airports, after completing a "curb-to-curb" study on airport operations.  They found that overall, the probability of being infected in an airport is very low. 

According to APHI, airports have made "consistent and impressive commitments to reduce the risks of disease transmission in their facilities" between passengers, employees, concessionaires, contractors, and visitors through layered, interlinked, risk-mitigation strategies that, when used together, can effectively control the risk of exposure. The report highlights enhanced cleaning and frequent disinfection regimens; upgrades to ventilation delivery and air handling systems (including increasing filtration efficiency); adoption of various means to encourage physical distancing (e.g., floor decals, barriers, signage, communication); promoting compliance with wearing masks or face coverings; and use of technology to support contactless procedures in certain circumstances. It concludes that these protective efforts must remain in place as air travel volumes increase and even as more and more people get vaccinated to reduce the transmission of this disease. 

The release of the report by Harvard's APHI is likely to generate renewed interest from the public and media in efforts individual airports have taken since the beginning of the pandemic to enhance public health. We recommend that you prepare for inquiries and take the opportunity to highlight the proactive steps your airport has taken to mitigate risk and promote public health in your facilities. 

In response to the report, AAAE President and CEO Todd Hauptli said:

"The assessment from Harvard's Aviation Public Health Initiative highlights the numerous, proactive steps and investments that airports across the country have undertaken to mitigate against the risk of transmission and safeguard the health and safety of the traveling public and all who work and travel through the airport environment. As public entities, airports are laser-focused on public health and have taken meaningful action to enhance cleaning and sanitization, promote training and education for employees, ensure proper distancing and the use of masks, upgrade ventilation systems, invest in touchless technology, and deploy other innovations to protect traveler and worker health and improve the airport experience. The report makes clear that there is no one-size-fits-all approach that works in all instances given the nature of the virus and the complexity and diversity of airports across the country, but the recommendations and strategies provided will be helpful as airports continue to evaluate and enhance the multiple layers of protection they have deployed."  

This report is the second by Harvard to assess the risk of transmission in air travel. The first report was issued in October 2020 and focused on the risks on aircraft. APHI acknowledged that the airport environment is much more complex, as compared to aircraft when it comes to studying transmission risks and mitigation efforts.

Information Collected from Airports: 

To better understand the airport environment, Harvard developed a questionnaire that focused on "airport operations in a public health emergency; screening of passengers, visitors, and employees; cleaning and disinfection; ventilation; physical distancing from pre-departure to arrivals; innovations, and behavioral issues." A total of 25 airports, 23 within the United States (U.S.) and two internationally, responded to the questionnaire. The sample of U.S. airports reflected different areas of the country, airport sizes, and international and domestic facilities. Based on their responses, Harvard interviewed a subset of these airports. 

APHI found that while information developed for addressing the pandemic was helpful to airports, the absence of federal guidance early in the crisis and variable state and local practices in the U.S., meant that each airport has largely been responsible for determining its approach to COVID-19 response protocols and the evolving science. Among the airports surveyed and interviewed, most commented on a desire to see greater consistency across the industry through federal requirements, noting this would help passengers know what is expected of them, improve passenger confidence and compliance, and enable targeted financial investments in support of faster industry-wide recovery.

Airports surveyed also expressed concerns about how to maintain physical distancing as travel volumes increased, tenant compliance with coronavirus related protocols, and the risk of airport employees catching the virus elsewhere and bringing it to work.

Areas of Potential Concern Identified in the Study: 

During its review of airport interventions to decrease the spread of the coronavirus from all known pathways, Harvard identified some potential areas of concern. Specifically:

  • Eating in gate areas: In some states, airport restaurants were required to close seated dining (even if properly spaced) in line with state or local rules. Food pickup and delivery to the gate were the only options available to travelers. The unintended consequence of this policy resulted in increased congestion at seated areas in departure gates and the mixing of unmasked (face mask removed to eat or drink) with masked travelers. APHI noted this as an example of where one precautionary measure could potentially exacerbate overall transmission risks. As a result, the Harvard researchers strongly discouraged eating at gate hold areas or other locations where crowding can occur.  

  • Physical barriers: Installing physical plastic or acrylic barriers at customer-facing service areas and passenger queuing areas can reduce the spread of exhaled virus plumes, however, they must be appropriately designed, sized, and ventilated to achieve this goal. APHI researchers expressed concern that barriers designed to separate queuing lines might create plastic ‘canyons' that inhibit airflow. While these barriers might offer some protection to others waiting in adjacent lines, a passenger in front or behind an infectious person is likely to experience concentrations higher than they would have in an open well-mixed space. Harvard does not recommend the installation of these partitions at queues where passengers are checking in, at security checkpoints, or customs and immigration inspection lines without first conducting a detailed analysis of the adequacy of the air change in those spaces as well as how air is mixed in the breathing zone of passengers waiting in these lines. These concerns may be alleviated in airports with high ceilings and with good vertical air mixing. 

  • Disinfection Devices: As part of their review of ventilation and filtration systems, APHI stated that airport ventilation systems are critical in reducing airborne transmission risk and highlighted several technologies that could help manage these risks. However, Harvard does not recommend airports install disinfection devices in their air ducts at this time because there has not been any third-party verification of their efficacy in preventing the spread of the novel coronavirus through mechanical ventilation systems. Further, the APHI researchers advised that disinfecting devices that emit ozone into the air should not be used in occupied settings under any circumstance because ozone can damage respiratory systems.   

  • Body temperature screening: The report opined that "it is unlikely that body temperature screening for COVID-19 in airport settings will be useful to mitigate risk" and is of marginal value Unlike other infectious diseases, like Ebola, only about one-third of infected persons develop a fever, most persons in the incubation phase when they are most contagious do not display any symptoms, and those symptoms can be masked by taking medicine to conceal a fever. If an airport chooses to check temperatures, it should be part of a multi-layered approach to detect sick travelers, consistent with guidance issued by FAA and ICAO last year. 

  • Behavioral compliance: The report noted that behavioral compliance is a particular challenge in the airport environment. The report recommended strategies that encourage compliance, including convincing vaccinated people to continue preventative behaviors for the duration of the crisis, as central to countering risks of transmission as people navigate the airport environment. 

COVID Testing: 

The Harvard researchers did not offer an opinion on mandatory COVID testing before travel. The report stated that "testing regimes should be framed as part of a broader evaluation of the need to reduce risk across many daily, routine activities…In the setting of air travel, viral testing should be viewed as a public health screening measure rather than a diagnostic clinical tool, with the more limited but important goal of identifying infected travelers and keeping them out of airports and off the aircraft." APHI recommended that pre-travel testing should be performed as close to travel as possible, namely the same day or one-day prior, using a test with appropriate sensitivity and specificity. However, they acknowledged a number of roadblocks to implementing a program requiring testing of all travelers. Specifically, they questioned the current supply and availability of quality tests; how to ensure that these limited supplies do not negatively affect others, such as schools and healthcare; the need for appropriate testing protocols that ensure the integrity of sample collection from the traveler; as well as considerations of costs, logistics and privacy issues.

Yesterday in a virtual meeting with DOT Secretary Pete Buttigieg, AAAE President and CEO Todd Hauptli joined other industry leaders in urging the rejection of a mandatory domestic testing requirement. AAAE has also joined other industry groups in circulating a white paper on the implications of domestic COVID-19 testing requirements for aviation.  

Links to Harvard's Report: 

  • Highlights and Summary. This document includes APHI's key findings on health screening and testing, disinfection and cleaning, physical barriers, physical distancing, ventilation, airport vehicles, combined mitigation efforts, behavioral strategies, as well as recommendations to airport operators, passengers, and employees. 

  • APHI Phase Two Report: Assessment of Risks of SARS-CoV-2 Transmission During Air Travel and Non-Pharmaceutical Interventions to Reduce Risk