Each year, livestock producers give thousands of injections to calves and cows. The vast majority of those injections go off without a problem.
However, there are times when producers may accidentally inject the vaccines or antibiotics into themselves or other helpers.
So what happens when a product, meant for a 1,000-pound cow, winds up inside a 200-pound human?
The results can be deadly.
“Some of these vaccines are toxic to humans. When people show up at their doctor there may be little that can be done,” said Dr. Donal O’Toole, with the University of Wyoming veterinary sciences department.
“There are also alarming reports of people having to have surgery done or get fingers amputated,” he continued. He related the account of a Wyoming veterinarian who accidentally injected himself with an anti-brucellosis vaccine and has “major problems” dealing with it ever since.
When accidental injections occur, producers should always seek medical advice immediately and show the package insert, data sheet, or vaccine label to the physician so they can take necessary steps to avert negative side effects.
“Actually take the vaccine box and data sheet with you,” said O’Toole. “Physicians are great but they don’t know about veterinary vaccines.”
If a data sheet is not available, the physician can find the information on the manufacturer’s Web site.
Dr. Bob Meyer, Wyoming Assistant State Veterinarian, agreed with the importance of seeking medical advice.
“Always contact a physician right away. Don’t wait. And take all the information with you. At the very least, with any accidental injection, the producer may need a tetanus booster to guard against the introduction of a contaminant,” Meyer noted.
For that reason, producers should also wash the site but avoid squeezing the injection site. That may actually force the vaccine deeper into the tissues.
A big problem with accidental injections is the adjuvant used in the vaccine.
There are adjuvants in human vaccines as well as animal vaccines. An adjuvant is a foreign toxin that is intentionally included in the vaccine to stimulate the immune system.
If a vaccine has an adjuvant in it, it may cause a lump or bump at the injection site. Many of the adjuvants in cattle vaccines are oil-based. Bovine, oil-based vaccines are most often used when treating bacterial problems, such as E. coli.
“That oil is very persistent and is meant to last in the body for weeks or months to stimulate a robust immune response in cattle,” O’Toole explained.
If that oil-based vaccine is accidentally injected into a human, it can cause swelling, stiffness and reduced blood flow at the site for long periods of time, even months.
In cattle, oil-based adjuvant vaccines are given in the neck area because the adjuvant can damage the muscle tissue and reduces the quality of the meat at the injection site.
Humans who suffer from accidental injections of those vaccines may suffer muscle and tissue damage around the site. In extreme cases, surgery may have to be done to get the oil out.
“Especially if the self-injection was deep into the muscle or around a tendon, it can be difficult to get the oil out without causing permanent damage,” said O’Toole. “If the vaccine can cause a lump on cattle, or if they are a killed vaccine product, producers need to be careful.”
Some vaccines are classified as modified live virus vaccines (MLVs).
This means they carry a small amount of the living disease agents that have been modified so that disease is not produced in vaccinated livestock.
Most of these live agents will not produce the disease in humans if an accidental injection occurs.
That is because the disease is not zoonotic, meaning it will not produce disease in humans.
However, Meyer said some live agents used in livestock may produce disease in humans if they are accidentally injected into the human body. As a result, a person could become very ill with the very disease they are trying to prevent in their livestock.
Meyer also used the example of an anti-brucellosis vaccine, which is a live, bacterial vaccine.
Because brucellosis can be contracted by both cattle and humans, the vaccine is restricted for use only by a veterinarian.
“If a veterinarian was accidentally injected with it, they could develop a case of brucellosis, or undulant fever, which is a very difficult disease to deal with,” said Meyer.
Still, there are veterinary products that can be dangerous to humans in other ways. Death from cardiotoxic effects can occur in people who accidentally inject themselves with an antibiotic called tilmicosin. This is a common antibiotic used to treat “shipping fever.”
“Tilmicosin just trashes the human heart,” said O’Toole.
Different vaccines are potentially harmful to certain groups of people.
Some products should not be handled by women or by people with poor immune systems. Other vaccines can cause allergic reactions in handlers who have allergies to compounds used in the vaccines.
“Some vaccines can cause anaphylactic shock in people who are allergy-prone,” cautioned O’Toole. Since not all the compounds used in a vaccine will be listed on the box, it can be risky for anyone with chemical sensitivities to handle a vaccine.
Accidental self-injections can occur anywhere on the body, although fingers and hands are the most common sites.
In the case of accidental injection or exposure, some reactions may appear fairly rapidly while others may take a few days to develop. For that reason, producers should always contact their physician, even if nothing appears to be happening.
Reactions may include redness, swelling and stiffness at the site of the accidental injection. Nausea, dizziness, anxiety, headache, an abnormal taste in the mouth, lightheadedness, chest pain, difficulty breathing, or increased heart rates are considered medical emergencies and should be dealt with immediately.
Do not wait until the last few cattle are run through the chute.
Even if they have given thousands of injections without a problem, handlers should always use caution to guard against accidental self-injection.
Vaccines change and so do their effects. Never become complacent when administering vaccines and be sure to have proper training.
Because toxins can enter the human system through needlesticks, existing cuts or abrasions, puncture wounds, direct skin contact, and even through the nose, eyes or mouth, handlers should guard against exposure by wearing needle-puncture-resistant gloves and safety glasses.
Handlers of vaccines should never hold syringes in their mouths.
“They also should not stuff loaded syringes in their overalls or their pockets,” said O’Toole.
Caps should be kept on needles until they are ready to be used.
Furthermore, all vials and needles used in the vaccination process should be placed into an approved sharps box so they don’t have to be gathered up later.
Picking up used needles or syringes from the ground later increases the risk of handlers being stuck or exposed during the cleanup process, and stepping or kneeling on a needle. All vials, needles and leftover vaccines should be disposed of by an approved method.
All animals should be properly restrained before administering the injection.
Even then, the jostling of animals can cause accidental human injections. For that reason, handlers should always take a visual on the location of their co-workers. They should also pay attention to where their own fingers are. It does not take much for a needle to pass through a fold of skin and pierce the handler or an assistant.
Avoid using automatic injection tools. These can inject a full dosage into a human body before there is even time to react. Many people will feel a needle prick from a hand-held syringe and jerk back, often before a full dose can be administered. With automatic injection tools, there is no time to respond.
Always read the insert directions and follow them exactly. Any medicine that is not administered in the recommended way can have unwanted consequences.
As an added measure of safety, persons with known allergies or women who are pregnant should not be giving injections to livestock or handling the vaccines and syringes.
“Most of all, take it easy,” said O’Toole. “Don’t be in a big hurry. The animals will get stressed, you’ll get stressed, and that’s when mistakes will happen. Trying to rush through the job is just asking for trouble.”