An issue related to a healthy agricultural workforce that has surfaced is the notion that individuals who work with dairy or beef cattle have a natural resistance or immunity to COVID 19. There’s a belief that exposures to the broader family of coronaviruses, such as, types that causes scours in pre-weaned calves, winter dysentery in confined dairy cows, or associated with certain pneumonias in cattle, provide this resistance.
This is a false belief that could be providing the agricultural workforce with a false sense of security. At this time, there is no known resistance for any human to COVID-19, including farmers, their families or their employees.
Dr. Christopher Olsen, DVM PhD, Office of Global Health, School of Medicine and Public Health at UW-Madison says, “The virus SARS CoV2 that causes COVID-19 disease is only distantly related to common bovine coronaviruses. While not impossible for there to be some level of cross-recognition of this new virus by antibodies to bovine coronavirus (they are in the same overall subsection of the coronavirus family), I would expect it to be very limited.”
Dr. Tom Freidrich, Professor in the School of Veterinary Medicine at UW-Madison and Head of Virology at the National Primate Research Center in Wisconsin where they study the source of viruses and how they make us sick adds, “because bovine corona virus’s don’t appear to infect human cells, it’s unlikely exposure to these viruses would stimulate much of any immune response in people”. He adds “bovine corona viruses are not particularly closely related genetically to the COVID-19 virus, so even if people with exposure to cattle could have some immunity to bovine corona viruses, I don’t think it would give much protection against COVID-19.” Furthermore, Dr. Freidrich says while human corona virus infections are quite common and most of us likely have some immunity to human corona viruses that cause the common cold, this does not appear to protect people against COVID-19. Overall he says, “I strongly recommend everyone assume they are susceptible to COVID-19. There’s not only an individual risk of developing severe disease if you get it, but it’s very contagious and would be easy to pass on to others once you’re infected.”
The good news is we don’t have to worry about the safety of food being produced on farms according to Dr. Gregg Hanzlicek, Kansas State University Veterinary Diagnostic Lab Director. He notes, “Milk, eggs, beef pork…whatever the source of your protein, people do not have to worry because those products don’t carry COVID-19.”