Coronavirus: infection shield to keep medical staff safe ‘increases risk 500pc’

Australian scientists have exposed a potentially lethal flaw in shields used to protect medical staff treating COVID-19 patients.

A diagram of a proposed Covid box.

Australian scientists have exposed a potentially lethal flaw in shields used to protect medical staff treating COVID-19 patients, forcing the world’s premier health regulator, the US Food and Drug ­Administration, to revoke authorisation of the devices.

The acrylic barrier enclosures, known as aerosol boxes, are supposed to protect doctors and nurses treating people on ventilators but were found to send the infection risk rocketing by 500 per cent or more. The FDA’s action will spur hospitals across the globe to scrap the devices, though few if any are believed to be in use in Australia.

As many as six local manufacturers are believed to be making aerosol boxes and some have been donated for trial in Melbourne hospitals.

Infectious disease specialist Peter Chan blew the whistle after examining an aerosol box delivered to the intensive care unit of Box Hill hospital in the city’s east. Five coronavirus sufferers were intubated there this week.

The devices enclose the ­patient’s head and upper body, with care administered through arm ports designed to contain viral particles expelled by coughing. On May 1, the FDA issued what is known as an umbrella emergency use authorisation for their use in COVID-related intubation and airway clearance.

But in a study for the ­Monash School of Public Health, Dr Chan’s team found that far from protecting workers, the aerosol boxes directed jets of virus-laced air at their faces, increasing the level of exposure fivefold.

“We were surprised to find airborne contamination of the doctor increased substantially using the aerosol box compared with all other devices and with no device use,” Dr Chan said. “Spikes of airborne particles were clearly seen, coinciding with patient coughing.

“We believe that they represent particles escaping from the arm access holes in the aerosol box.”

A second Monash University research team, led by Jonathan Begley and David Brewster, found the boxes often ripped the gloves and protective gear of medical staff using the arm holes. The barrier, though see-through, also ­obstructed doctors while intubating patients, a delicate procedure to place a breathing tube down the throat.

Withdrawing its emergency use authorisation, the FDA cited the Australian findings as ­“preliminary evidence” that the devices could do more harm than good. Healthcare providers “should be aware of potential risks of complications associated with their use so they can take appropriate precautions”, the agency said. “Based on this information, the FDA is revoking the current umbrella EUA for passive protective barrier enclosures issued in May … the devices covered by the umbrella EUA are not approved and no longer authorised by FDA for any indication.”

Dr Chan said thousands of aerosol boxes were in use overseas, particularly in the US and South America.

He said the lesson was that personal protective equipment for COVID healthcare workers needed to be as closely evaluated as new treatments and vaccines.

“If this box was sold as a product, and therefore regulated, it would likely need to be immediately recalled,” he said. “Healthcare workers might be continuing to increase their exposure to COVID-19 while thinking they are protecting themselves.”