They studied how it spreads, how vaccines work, how long immunity lasts, and how fast a campaign must move to outrun the next outbreak. They then engineered programmes that match the biology.
South Africa is doing something different. It is treating FMD as an administrative exercise. Doses imported. Provinces allocated. Targets announced. Percentages reported.
The virus does not follow government timelines. It does not pause for committee meetings or wait for provincial rollouts to catch up. It only cares whether the next animal is susceptible.
“80% of the national herd vaccinated over the next 12 months” sounds like progress. It is not the same thing as 80% of the national herd protected at the same time. Until South Africa understands that difference, it will not regain FMD-free status with vaccination.
Key terms
Duration of protective immunity. How long an animal is meaningfully protected after vaccination. Manufacturer data for the oil-based FMD vaccines being deployed in South Africa indicate approximately six months of protection.
Booster interval. The point at which the animal must be revaccinated to maintain protection. If practical protection lasts six months, the system must be built around a six-month rhythm.
Vaccination window. A short, defined period in which a target population is vaccinated together. A window has a start date and an end date. Its purpose is to create immunity across the population at the same time, as quickly as possible.
Vaccination cycle. The repeated rhythm of vaccination windows: a window, maintained protection, then another window before immunity wanes.
Vaccination coverage. WOAH defines this as the proportion of the target population to which vaccine was administered during a specified timeframe.
Population immunity. WOAH defines this as the proportion of the target population effectively immunised at a specific time.
Vaccination coverage tells us how many animals were injected. Population immunity tells us how many animals were protected at the same time. These are not the same number.
Vaccination windows are not optional
WOAH’s Terrestrial Animal Health Code requires vaccination campaigns to be designed so that the “majority of the target population is immunised within as short a time as possible.” This standard sits in Chapter 4.18 of the Code.
A campaign must have a start date, an end date, and the speed to interrupt viral circulation. This is not a stylistic preference. It is the operational expression of the WOAH standard.
A vaccination window concentrates immunity. The animals are protected together, at the same time, across the same geography.
The dossiers and control programmes of countries that have achieved FMD-free with vaccination status show what the standard means in practice. Their vaccination campaigns are typically completed in 30 to 60 days.
No country has achieved FMD-free with vaccination status by relying on a slow, rolling campaign.
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Vaccination cycles are not optional either
A vaccination programme is not one rollout. It is a repeating biological rhythm.
If the duration of protective immunity is around six months, the country needs repeated windows roughly six months apart.
The first window builds the immune wall. The second window renews immunity before it drops. Subsequent windows maintain protection.
One vaccination window may slow an outbreak. Repeated vaccination cycles maintain control.
Population immunity is the real target
Now the core problem.
The Government’s “80% over 12 months” target measures vaccination coverage over time. It does not measure population immunity at any single point in time.
80% vaccinated over 12 months is not 80% immune at the same time. By the time the last animals in the campaign are vaccinated, the first animals are already at the end of their six-month booster interval. Their protection is declining. The wall is being built at one end while it crumbles at the other.
Add the routine pressures of a real campaign. Missed herds. Weak records. Late provinces. Animals that fail to seroconvert. Doses mishandled in the cold chain.
FMD does not need a wide-open door. It finds the gap.
A cumulative vaccination target is not an immune wall.
Simplified illustrative comparison. Top: 80% coverage spread over 12 months never lifts population immunity to the threshold. Bottom: 90% in 8 weeks with a booster at six months builds and holds the wall. The vertical axis is the proportion of the herd protected at any given moment, not cumulative doses.
Why 90% must be vaccinated to reach 80% immunity
This is not an editorial extrapolation. OIE/WOAH guidance says it directly.
In its 2018 guidance the Organisation explains that because not all vaccinated animals respond fully to the vaccine, and because there will always be occasional problems delivering vaccine to individual animals, vaccination strategies should aim for at least 90% coverage of the target population, so that at least 80% achieves protective antibody levels. Post-vaccination monitoring is then used to verify this, and the strategy adjusted if measured protection falls significantly below 80% (WOAH, 2018, p. 1).
This is what every successful FMD control programme has built around.
Some animals will be missed. Some will not respond. Some records will be wrong. Some doses will be mishandled. Some herds will be late.
If the goal is 80% effective immunity, the vaccination target cannot be 80%. It must be closer to 90%.
That is the operational scale a serious national programme has to be built to deliver.
What Brazil’s model actually shows
Brazil shows the operating logic of a serious FMD campaign system. Tight vaccination windows. Repeated cycles. National coverage delivered in short, defined campaigns rather than rolling administrative drift.
That architecture is far closer to what South Africa needs.
The vaccine moved through regulated private channels. The state set the standards: which vaccine, which strains, what potency, what records, what audit. Producers were responsible for getting their animals vaccinated through approved channels within the defined window, with private service providers and veterinarians supporting delivery where required. Vaccination had to be declared and recorded. The state audited compliance and enforced penalties.
The state did not personally inject every animal. It did not procure or distribute every dose. It did something more important. It made the system work.
Brazil did not remove the state. It put the state in the right place: setting standards, enforcing compliance and auditing proof.
This is the architecture South Africa needs. The state holding the standards, the audit, the enforcement and the regulatory authority. The private sector carrying the load: manufacturers, importers, veterinarians, producers. Vaccine flowing from manufacturer to veterinarian to farmer, on a timetable that matches the biology of the virus.
What South Africa actually needs
South Africa’s problem is not that it has chosen vaccination. Vaccination-to-freedom is a legitimate WOAH pathway, used successfully by many of the world’s major livestock-producing nations.
The problem is that South Africa is treating vaccination as an administrative process when it is a biological control system.
FMD-free with vaccination will not be achieved by optimism, vaccine arrivals or a year-end percentage. It will be achieved when South Africa creates enough immunity, in enough animals, at the same time, before the virus finds the gaps.
That means vaccinating closer to 90% of the national herd in tight 8-week windows, repeated roughly six months apart, with the state setting standards and auditing the proof. Not a rolling campaign stretched across the year.
South Africa does not need a vaccination story. It needs an immunity system.
