A couple of months ago a video was posted on social media that messenger RNA (mRNA) vaccine technology was being used on cattle. Of course, this was and is false information, but did raise multiple concerns and statements were released from NCBA to confirm that this technology is not being used on cattle. These statements also confirmed that a mRNA vaccine is not approved for use in cattle, and this type of vaccine is not even commercially available for use. I even received questions on this topic at some of the Master Beef meetings that occurred around that time. With concerns such as these, it would be a good time to cover some of the basics of vaccines so that you can have an understanding if you are approached with questions.

Modified-live virus vaccines (MLV)

MLV vaccines contain a weakened or attenuated form of a live virus (antigen). Because the virus has been altered, it should not cause clinical disease, but will very closely mimic a true infection.

Once the vaccine is administered, the virus will replicate within the animal’s system and create the opportunity for an immune response through the production of antibodies. These antibodies then respond to fight infection if exposed to the natural virus later. A MLV vaccine will typically come packaged as two separate bottles that require mixing.

Modified Live Vaccines (MLV)
Advantages:   -One initial dose may be sufficient, but boosters are sometimes required -Stimulate more rapid, stronger, and longer- lasting immunity than KV products -Less likely to cause allergic reactions and post-vaccination lumps -Usually less expensive than KV products	Disadvantages: -Risk of causing abortion or transient infertility, therefore, they should be administered 6-8 weeks prior to breeding. season -Must be mixed on-farm and used within about 30 minutes to 1 hour

Killed Vaccines

Killed vaccines contain an inactivated, or killed, antigen that is incapable of replicating in the animal’s system. Because the killed virus does not have that opportunity to replicate, killed vaccines usually require a booster dose. The killed vaccine requires more viral antigen, or pieces of the virus, to get enough immune system recognition after administration, and is prepared with an adjuvant to create an immune response. Typically, killed vaccines are packaged as a single bottle.

Killed Vaccines (KV) and Toxoids
Advantages:   -Available for many diseases -No risk of the vaccine organism spreading between animals -Minimal risk of causing abortion -No on-farm mixing required	Disadvantages:   -More likely to cause allergic reactions and post-vaccination lumps -Two initial doses required -Slower onset of immunity -Immunity is usually not as strong or long- lasting when compared to MLV products -Usually more expensive than MLV products

mRNA Vaccines

mRNA vaccines are a relatively new type of vaccine. An example of an mRNA technology vaccine is the COVID-19 vaccine. The vaccine contains genetic material, the messenger RNA, which tells the body how to make a protein. mRNA then provides a recipe that cells can use to make proteins. After injection, the cells in the muscle pick up the mRNA, make the protein, and display it on the cell’s surface. The immune system sees the protein and learns how to make an immune response against it. This protein causes an immune response, which teaches the body how to protect itself from a specific virus by producing antibodies against that virus.

It would be false information to say that mRNA vaccines for cattle do not exist. In fact, trial studies have been conducted on cattle at some research facilities. But here is the important thing to for you to know, none of the trial vaccines are USDA approved for use in cattle. That means the mRNA technology vaccines cannot be used. If you did not see the statement from NCBA, I have included it along with additional information.

“There are no current mRNA vaccines licensed for use in beef cattle in the United States. Cattle farmers and ranchers do vaccinate cattle to treat and prevent many diseases, but presently none of these vaccines include mRNA technology.”

• Research on mRNA vaccines for use in livestock has been ongoing for more than a decade, which suggests that at some point mRNA vaccines may be available for use in U.S. cattle. However, this will not happen before there has been sufficient research and significant layers of government review and approval.
• Modified-live vaccines containing RNA from viruses such as bovine viral diarrhea virus (BVDV), bovine respiratory syncytial virus (BRSV), rotavirus, and coronavirus have been licensed and used by U.S. producers for many years.
• No vaccines currently licensed in the U.S. for administration to cattle were produced using mRNA technology.
• Currently there are no mRNA vaccines licensed for use in cattle in the U.S. New prescription vaccines in swine can use RNA of specific viruses, which is similar to mRNA vaccines, but not exactly the same.
• Regardless of the vaccine technology, the components of vaccines are ‘digested’ or broken down by immune cells after they are given so the components do not persist in animal tissues for long periods of time.
• Following the withdrawal times on vaccine labels helps to ensure that meat from vaccinated animals is safe to consume.

If you have any questions concerning mRNA vaccines as compared to traditional, please feel free to contact me at, 865-974-3538, lstrick5@utk.edu, or askdrlew.tennessee.edu.

Resources: Pfizer.com

NCBA.com