Why Vaccination Is Central to FMD Control
Foot-and-Mouth Disease spreads with extraordinary speed. A single infected animal can contaminate an entire herd within days. Vaccination is widely recognised as one of the most effective strategies for reducing the impact of FMDV — both protecting individual animals and reducing the overall viral load in a population, which slows transmission.
However, FMD vaccination is not as straightforward as many other livestock vaccines. Understanding the nuances is essential for any farmer or herd manager operating in or near FMD-risk areas.
How FMD Vaccines Work
FMD vaccines are inactivated (killed) virus vaccines. They stimulate the animal's immune system to produce antibodies against the virus without using live FMDV. Key points:
- Vaccines must be matched to the specific serotype(s) circulating in a region — a vaccine against serotype O will not protect against serotype A.
- Protection is not lifelong. Boosters are required, typically every 6 to 12 months depending on the vaccine type and local risk level.
- Vaccinated animals may still become sub-clinically infected and act as carriers, which has implications for testing and disease-free status declarations.
Vaccination Schedules: General Guidance
Vaccination programs vary by country, local disease pressure, and species. The following is general guidance — always follow your national veterinary authority's recommendations:
- Primary vaccination: Two doses given 4–6 weeks apart provide foundational immunity.
- Booster doses: Administered every 6–12 months to maintain protective antibody levels.
- Young animals: Calves born to vaccinated mothers may have maternal antibodies that interfere with early vaccination — timing the first dose correctly is important, often at 4–6 months of age.
- Pre-outbreak vaccination: In zones bordering active outbreaks, emergency vaccination campaigns may be deployed to create a protective buffer.
Biosecurity Measures That Work Alongside Vaccination
Vaccination alone is not sufficient. A strong biosecurity plan is essential to maximise protection:
- Control farm access: Limit visitors, vehicles, and equipment entering livestock areas. Maintain visitor logs.
- Disinfect thoroughly: Use approved disinfectants on footwear, wheels, and equipment. FMDV is sensitive to acids and alkalis — citric acid and sodium carbonate solutions are commonly used.
- Quarantine new animals: All new animals should be isolated for at least 21 days before joining the main herd and confirmed free of disease.
- Avoid livestock markets during outbreaks: Markets and shows are high-risk gathering points where disease can rapidly spread between herds.
- Manage feed and water sources: Avoid feeding untreated food waste (swill feeding is banned in many countries for this reason).
Distinguishing Vaccinated from Infected Animals (DIVA)
Modern FMD control relies on the ability to differentiate between animals that are vaccinated but healthy and those that have actually been infected. This is known as the DIVA (Differentiating Infected from Vaccinated Animals) strategy. Special diagnostic tests — particularly those detecting antibodies to non-structural proteins (NSPs) of FMDV — allow veterinarians and authorities to make this distinction, which is critical for trade certifications and FMD-free status maintenance.
Working With Your Veterinarian
FMD vaccination programs should always be developed and supervised by a licensed veterinarian with knowledge of local disease risk. Your vet can:
- Advise on the correct vaccine serotype(s) for your region
- Ensure cold chain integrity (vaccines must be stored at 2–8°C)
- Conduct serological monitoring to check herd immunity levels
- Report any suspected adverse reactions or vaccine failures
Consistent vaccination, combined with strong biosecurity and active surveillance, gives your livestock the best possible protection against this devastating disease.