Although a third U.S. dairy worker has been confirmed to be infected with the H5N1 bird flu, many dairy farms are still unwilling to use even freely offered personal protective equipment (PPE). This is cause for alarm. Working with a pathogen assigned a biosafety level of 3 — meaning it “can cause serious or potentially lethal disease through respiratory transmission” — with at best BSL 2 level protections is playing with fire.
This lack of protection leaves farmworkers who interact with potentially infected animals, including dairy cows, chickens, and alpacas, at risk for infection with a virus that has killed half of the people in whom it was diagnosed. And the more H5N1 is able to interact with and infect people, the greater the risk that it might accumulate the handful of mutations it needs to become capable of human-to-human transmission, a stepping stone to a possible epidemic.
The single most effective way to ward off a potential crisis of H5N1 bird flu and to protect farmworkers is to ensure they have usable and effective PPE. While several experts have rightfully called for widespread testing of farm animals and workers, many farm owners and workers have been reluctant to test due to concerns of losing work, the undocumented status of many workers in this sector, and financial loss. Even if uptake of testing did improve, it would still identify infections only after they occur. Workers would still be in danger and H5N1 would still be given chances to evolve and potentially leap to human transmissibility. Using PPE to seal the human-animal interface from spillover infections is the only way to protect workers and eliminate the chance for H5N1 to crossover in the first place.
Species in the wild, into whom H5N1 has recently crossed, have little interaction with humans. Dairy cattle, chickens, and alpacas, however, are farm animals with whom humans interact on a daily basis. Dairy farms, in particular, pose a unique and heightened risk. The milking process requires workers to spend up to 12 hours a day in direct close contact with cows. Udders have high viral loads and spew infected milk that can readily get into eyes, noses, and mouths, or onto hands and surfaces from where infection could get seeded. There is also the possibility that some H5N1 virus is airborne and causes infection via inhalation. It’s no surprise that all three H5N1 bird flu cases detected in the U.S. have been among dairy workers.
The Centers for Disease Control and Prevention recently issued recommendations for farmworkers to use PPE but, given the stakes, a more urgent and rigorous federal effort is needed to ensure that dairy and other animal workers use PPE that is effective and matched to their workflow and conditions.
This is a solvable engineering and cost problem. Greater efforts should be made to understand and target the particular reasons why workers are not using PPE. With the CDC recommendations as a starting point, infection control experts should go through farmworkers’ entire workflow and, with their input, identify the best options for PPE that is adequately protective yet also practically wearable.
The highest infection risk seems to be via the face — either infectious milk or secretions getting into the eyes, nose, or mouth, or possibly airborne inhalation. The CDC advises using N95 or elastomeric respirators with goggles or face shields. But the conditions in milking parlors make disposable N95s ineffective when they get wet, and cause goggles and face shields to fog. Elastomeric respirators and goggles remain somewhat effective when wet, but, like disposable N95s, are difficult to wear for long stretches, especially in the heat.
A better option for full head protection could be powered air-purifying respirators (PAPRs), which provide constant filtered airflow into an enclosed hood or helmet. Some PAPRs also have a temperature control. While these devices cost somewhere between $1,000 and $3,000 apiece, similar battery-powered industrial helmets could provide analogous filtration and protection without the potentially cumbersome tubing of a PAPR for about $500.
Hands and forearms also need to be reliably protected to prevent infection via breaks in the skin or by later touching the face. Impermeable gloves with sleeves could be used with strict protocols for donning, doffing, and hand-washing.
Securing the face and hands may eliminate most transmission risk. Fluid-resistant aprons could also be used to limit splashing on the rest of the body and clothing. Whole-body suits would be more thoroughly protective, but their impermeability may cause them to be difficult to wear in the heat and not worth pursuing if they offer little added infection prevention. If full body protection does, however, seem to be necessary, air or water-cooling garments as well as mandatory cooling breaks could be considered to mitigate the risks of heat stress.
There are approximately 150,000 dairy workers in the U.S. Doing extremely simplistic back-of-the-envelope projections, even if it cost $2,000 to protect each worker, the total bill of about $300 million would pale in comparison to the costs of responding to an epidemic of H5N1 bird flu, not to mention the broader economic and social toll of such a crisis.
These costs should be borne by the federal government. Expecting farm owners to foot this bill would kill any chance of it happening, and would unfairly lay on them a public societal responsibility. State governments should be tasked with coordinating with farm owners on distributing PPE and training workers on its use. The gravity and rationale of reliably using PPE should also be made clear to farm owners and workers. Once the potentially catastrophic implications are understood, many would likely be willing to do what they could — even when burdensome — to help avert a crisis.
The U.S. is at a crucial juncture with the H5N1 threat. But it has the opportunity to prevent its crossover into humans if animal farm workers get the protection they need, and use it.
Ranu Dhillon is an instructor and global health physician at Harvard Medical School and Brigham and Women’s Hospital in Boston who served as a special adviser to the government of Guinea during the 2013-2016 West African Ebola epidemic. Devabhaktuni Srikrishna is the founder of www.patientknowhow.com, which curates patient educational content on YouTube, including information on N95 masks and high-quality alternatives.