During the ongoing COVID-19 pandemic, the U.S. Department of Defense (DoD) has quickly and safely transported COVID-19-infected warfighters and civilians by aircraft to hospitals for care. Inside the aircraft, patients rested in biocontainment systems to prevent aerosolized severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19, from infecting the aircrew and contaminating the aircraft.
If aircraft contamination were to occur, the U.S. Air Force can use a modified Joint Biological Agent Decontamination System (JBADS) process, referred to as JBADS Lite, for hot-air decontamination. JBADS Lite provides rapid, effective decontamination of an aircraft’s interior for SARS-CoV-2 and other enveloped RNA viruses.
The Defense Threat Reduction Agency’s (DTRA) Chemical and Biological Technologies Department, in its role as the Joint Science and Technology Office (JSTO), generated data that allowed for successful implementation of JBADS Lite.
DTRA-JSTO had previously developed JBADS processes to more efficiently destroy persistent biological threat agents, such as Bacillus anthracis spores. Using an enclosure to house the aircraft, standard JBADS processes use a hot and humid environment of 170–190 degrees Fahrenheit, which are temperatures just below the safety limits for the equipment in the aircraft. The environment is sustained for three days until both the interior and exterior of the aircraft are disinfected. Lower temperatures and shorter times could disinfect aircraft interiors of other biological threats, such as viruses, but these temperatures and times were not known.
To explore decontamination procedures at reduced times and temperatures for viruses, DTRA-JSTO supported researchers at the Naval Surface Warfare Center Dahlgren Division (NSWCDD) from 2015 through 2017. Researchers developed laboratory decontamination processes using Phi6, a virus that poses no threat to humans. The Phi6 served as a surrogate for other human viruses, such as SARS-CoV-2, because such experiments are seldom performed using actual biological threat agents that can cause infections in humans. Using Phi6, NSWCDD researchers performed over 20,000 separate laboratory tests that showed that an environment of 143 degrees Fahrenheit at 90% relative humidity destroyed all detectable infectious Phi6 virus in one hour. Researchers next needed to validate their laboratory findings through demonstrations in the field on actual aircrafts.
In May 2020, NSWCDD researchers demonstrated the effectiveness of the JBADS Lite process on two aircrafts. The first demonstration used a derelict C-130 Hercules at Aberdeen Proving Ground, Maryland; the second demonstration used an operational U.S. Air Force C-17A Globemaster at Dover Air Force Base, Delaware. The demonstrations did not include enclosures for the aircrafts, so only an aircraft’s interior was exposed to the hot and humid air. Before decontamination, NSWCDD researchers placed high concentrations of infectious Phi6 on material coupons, or swatches of material used inside the aircraft. After the decontamination, researchers analyzed the material coupons for any remaining infectious virus. In both demonstrations, JBADS Lite achieved the targeted disinfection level: the amount of virus present inside the aircraft decreased by at least 10,000- fold or 99.99%. The decontamination process for the C-17A — setup, hot-air treatment of one hour, and breakdown — took three hours and 15 minutes, proving that the modified system is practical and effective for rapid disinfection.
The aircraft demonstrations are significant for two other reasons. First, they showed that JBADS Lite can reduce the survival of an infectious, enveloped RNA virus, such as SARS-CoV-2, by greater than 99.99% in less than four hours. The U.S. Department of Defense (DoD) can deploy JBADS Lite at a greater rate than the standard JBADS because the modified process needs lower temperatures to disinfect an aircraft’s interior of enveloped RNA viruses and does not need an equipment enclosure. Second, the field demonstrations were the first to use Phi6 as a surrogate for an enveloped RNA virus and develop methods for using the virus in a hot-air decontamination of an aircraft. Phi6 does not affect humans or animals, so its use by NSWCDD researchers sets a precedent for safe field demonstrations in the future.