While effective vaccines for COVID-19 should have heralded the benefits of mRNA vaccines, fear and misinformation about their supposed dangers circulated at the same time. These misconceptions about mRNA vaccines have recently spilled over into worries about whether their use in agricultural animals could expose people to components of the vaccine within animal products such as meat or milk.
In fact, a number of states are drafting or considering legislation outlawing the use of mRNA vaccines in food animals or, at minimum, requiring their labeling on animal products in grocery stores. Idaho introduced a bill that would make it a misdemeanor to administer any type of mRNA vaccine to any person or mammal, including COVID-19 vaccines. A Missouri bill would have required the labeling of animal products derived from animals administered mRNA vaccines but failed to get out of committee. Arizona and Tennessee have also proposed labeling bills. Several other state legislatures are discussing similar measures.
I am a researcher who has been making vaccines for a number of years, and I started studying mRNA vaccines before the pandemic started. My research on using mRNA vaccines for cattle respiratory viruses has been referenced by social media users and anti-vaccine activists who say that using these vaccines in animals will endanger the health of people who eat them.
But these vaccines have been shown to reduce disease on farms, and it’s all but impossible for them to end up in your food.
Traditional animal vaccine approaches
In food animals, several types of vaccines have long been available for farmers to protect their animals from common diseases. These include inactivated vaccines that contain a killed version of a pathogen, live attenuated vaccines that contain a weakened version of a pathogen and subunit vaccines that contain one part of a pathogen. All can elicit good levels of protection from disease symptoms and infection. Producing these vaccines is often inexpensive.
However, each of these vaccines has drawbacks.
Inactivated and subunit vaccines often do not produce a strong enough immune response, and pathogens can quickly mutate into variants that limit vaccine effectiveness. The weakened pathogens in live attenuated vaccines have the remote possibility of reverting back to their full pathogenic form or mixing with other circulating pathogens and becoming new vaccine-resistant ones. They also must be grown in specific cell cultures to produce them, which can be time-consuming.
There are also several pathogens – such as porcine reproductive and respiratory syndrome virus, foot and mouth disease virus, H5N1 influenza and African swine fever virus – for which all three traditional approaches have yet to yield an effective vaccine.
Another major drawback for all three of these vaccine types is the time it takes…