How Anti-Vaccine Conspiracies Threaten the Equine Industry

Katelin Parsons, , Comments Off on How Anti-Vaccine Conspiracies Threaten the Equine Industry
Vaccination is one of the most effective methods for prevention of equine infectious diseases. Vaccines help protect horses from potentially life-threatening diseases, but some owners are choosing not to vaccinate — and encouraging others to do the same.

Despite indisputable evidence that vaccines reduce the risk of severe illness and death, a rising number of horse owners are opting not to vaccinate their horses. In the wake of recent events, some owners have declared their anti-vax stance on social media. This is alarming and could threaten our industry as well as the lives of our horses.

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Why is it necessary to vaccinate horses?

It is necessary to vaccinate horses, especially horses that travel and compete, because vaccines are proven to prevent the spread of infectious diseases. Vaccines work by stimulating the immune system to create antibodies that fight off disease. Most vaccines contain antigens, which are markers – generally proteins or polysaccharides – that are found on the outside of bacterial cells and viruses. The immune system recognizes antigens as a threat and responds by creating antibodies to fight the perceived infection. The immune system also creates memory cells that can combat natural infections in the future. The antibodies and memory cells remain in the horse’s system for months, providing immunity against the targeted disease.

An illustration from the World Health Organization on how antibodies respond to specific antigens.

The type of vaccines needed by a particular horse depend upon several factors, including its age, exposure risk and geographic location. For example, vaccines for Influenza, Rhinopneumonitis and Strangles, often are required for horses that travel off the farm. Encephalomyelitis and West Nile, two infections that can lead to death, are transmitted by mosquitos. All horses need an annual vaccine for those diseases. All horses also should receive a yearly Rabies vaccine because it is almost always fatal and can be transmitted to humans. Additional vaccines for Rotavirus are highly recommended for pregnant mares to prevent them from aborting their foals. A veterinarian can advise on the best vaccination schedule for a particular horse.

Since 2015, the United States Equestrian Federation has required all horses entering the grounds of USEF sanctioned competitions to have documentation of Equine Influenza Virus and Equine Herpes Virus (Rhinopneumonitis) vaccinations. This rule was created in response to an Equine Herpes outbreaks that could have been prevented by vaccines. The Fédération Equestre Internationale (FEI) also requires proof of Influenza immunization. In addition to competitive organizations, some states have legal requirements for equine vaccination. Most equine insurance companies also require horses to be vaccinated in order for coverage to apply.

An illustration from the WHO showing how a new antibody is created in response to vaccine can recognize an actual threat later.

Why are people choosing not to vaccinate their horses?

Although the efficacy of vaccines in reducing the severity of illnesses is undeniable, a growing number of horse owners are electing not to vaccinate their horses. The reasons for their refusal to vaccinate vary. Some are worried about side effects from vaccines, but many just do not believe in them.

Here are some common misconceptions about vaccines:

  • Opinion: The side effects of vaccines are too risky.
  • Fact: The risk posed by infectious diseases is far greater than the risk posed by vaccinations. According to the American Association of Equine Practitioners (AAEP), the possibility of adverse reactions exists with the administration of any vaccine. Severe reactions that require veterinary treatment are rare. Most horses experience mild, short-term reactions like soreness at the injection site, a slight fever, or temporary lethargy. To reduce the risk of adverse reactions, vaccinations should be administered by a licensed veterinarian. Precautions, such as administering vaccinations over a three-to-four-week period, rather than all at once, should be taken for animals whose immune status may be compromised due to disease or immunosuppressive medications.
  • Note: Adverse events should be reported to the USDA Center for Veterinary Biologics at (1-800) 752-6255.

 

  • Opinion: Antibodies last a lifetime so annual or bi-annual vaccination is not necessary.
  • Fact: Antibodies do not last a lifetime. The protection provided by vaccines gradually declines over time. Although recent peer-reviewed studies suggest that horses can maintain protective antibody levels for up to three years after receiving vaccines for Rabies and Tetanus, these studies are not definitive. Further research is needed to determine if it is safe to increase the duration between doses of those vaccines. For now, annual vaccinations for Rabies and Tetanus and other potentially fatal diseases are still highly recommended to maintain a consistent level of immunity.
  • Note: If a horse owner wants to measure the level of immunity in their horse, they can have their veterinarian draw blood for a titer test. A titer test measures the number of antibodies in a horse’s blood that fight a specific disease. The results indicate the strength of the horse’s immune response and whether the horse has been exposed to particular diseases. There are instances where titer tests will be recommended by veterinarians for making vaccination decisions. These tests often cost between $70 to $100. In cases where they are not necessary, it is more cost-effective simply to vaccinate.

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  • Opinion: If they choose not to vaccinate their horses, it should not matter because horses that are vaccinated should be protected. The fact that horse owners with vaccinated horses are worried about their horses being unvaccinated is just proof that vaccines do not work.
  • Fact: To achieve effective herd immunity in horses, a significant portion of the population needs to be vaccinated. Experts generally recommend a vaccination rate of around 70-80% to adequately protect even vaccinated horses. The exact percentage can vary depending on the specific disease and local conditions. If the vaccination rate drops, all horses — vaccinated and unvaccinated — could be at risk of contracting potentially fatal diseases.

A core vaccine chart from the American Association of Equine Practitioners and the Equine Disease Communication Center

What can we do?

The horse owners who believe that vaccinations are ineffective or toxic because of some articles or posts that they read on the internet are not likely to be persuaded by peer-reviewed, scientific evidence. So, what can we do to protect our horses?

First, we should keep immunizing our horses based on recommendations by veterinarians. Even though herd immunity is required for most vaccinations to protect populations of horses, they are still our best defense against fatal diseases.

Another possible solution would be to encourage more organizations to take the same stance as USEF and FEI. If more events require proof of vaccination, more owners might choose to vaccinate their horses. Competing and attending events are privileges that individuals choosing to put others’ animals at risk should not get to enjoy.

Finally, be sure to practice good bio-security measures when traveling with your horses:

  • Do not allow nose-to-nose contact
  • Don’t share water buckets, feed bins, or hay with horses that aren’t stabled with your horse
  • Don’t allow public grazing
  • Maintain a safe distance from other horses
  • Disinfect any stalls that your horse will be using while away from home before they enter
  • Remove any used bedding in stalls when away from home and replace it with clean bedding

Unfortunately, this anti-vaccine movement will mean that we will have to stay vigilant. Outbreaks of preventable diseases may become more common. We will have to readily share information about local and regional outbreaks so that we know when to keep our horses at home. You can visit the Equine Disease Communication Center for information on how to report a disease.

Let’s all be smart and do what we can to prevent disinformation from impacting the equestrian sports that we enjoy.

Sources: Equine Disease Communication Center, American Association of Equine Practitioners, Equine Disease Communication Center, Tennessee Equine Hospital, PennState Extension, World Health Organization