Jordan study finds strong FMD cross-immunity in sheep and goats
Bottom line
Version 1 — Brief
A new Frontiers in Veterinary Science field study reports that a commercially used polyvalent, inactivated foot-and-mouth disease vaccine generated strong neutralizing antibody responses in goats and sheep in Jordan, including against a heterologous serotype O field strain that had circulated in the country. The study followed naïve small ruminants given either one dose or a day-28 booster, and found broadly similar immunity against the vaccine-matched strain and the Jordan field strain, with stronger and longer-lasting responses in goats than in sheep. The work builds on Jordan’s 2022-2023 vaccination campaign and earlier vaccine-matching work tied to the O/ME-SA/PanAsia-2/ANT-10 lineage that circulated in Jordan in 2021. (frontiersin.org)
Why it matters: For veterinary professionals, the study offers field evidence that a commercially deployed vaccine can provide meaningful cross-immunity in small ruminants, not just in controlled lab settings. That matters in a region where FMD remains endemic or recurrent, recent SAT2 outbreaks have underscored ongoing pressure on control programs, and vaccine performance depends on both antigenic match and campaign execution. The data also reinforce a practical point for flock health planning: booster dosing appears especially important for maintaining protection in sheep, which showed lower and less durable responses than goats. (woah.org)
What to watch: Watch for follow-up post-vaccination monitoring, especially on durability, species-level differences, and how well current vaccine portfolios cover newer regional strains such as SAT2. (foot-and-mouth.org)
Key facts
- Study type
- Field study
- Location
- Jordan
- Species
- Goats and sheep
- Vaccine type
- Commercial polyvalent, inactivated foot-and-mouth disease vaccine
- Vaccine strains
- O1 Campos, plus two serotype A strains
- Challenge strains
- O BFS and O JORD
- Dosing
- Single dose or booster at day 28
- Main finding
- Robust neutralizing antibodies against both homologous and heterologous serotype O strains
- Species difference
- Goats had stronger and longer-lasting responses than sheep
Version 2 — Full analysis
A new field study from Jordan adds real-world evidence that a commercial foot-and-mouth disease vaccine can do more than protect against its matched strain. Writing in Frontiers in Veterinary Science, researchers found that vaccinated goats and sheep developed robust neutralizing antibodies not only against the homologous serotype O strain in the vaccine, but also against a heterologous serotype O field strain that had recently circulated in Jordan. (frontiersin.org)
That finding lands in a region where FMD control remains a moving target. WOAH describes FMD as a severe, highly contagious transboundary livestock disease with major production and trade consequences, and stresses that vaccine strains need to match viruses circulating in the field. In the Middle East, WOAH says recent outbreaks, including SAT2 in Jordan, Iraq, and Türkiye, continue to test surveillance and vaccination systems. Jordan’s own recent history helps explain the study’s importance: the paper notes circulation of serotype O O/ME-SA/PanAsia-2/ANT-10 in 2021, while reference-lab and ministry-linked reporting points to a major national vaccination push in late 2022 after outbreaks. (woah.org)
The study design was straightforward and practical. Researchers vaccinated naïve goats and sheep in Jordan with a polyvalent inactivated product containing one serotype O strain, O1 Campos, and two serotype A strains. Some animals received a single dose, while others got a booster 28 days later. Antibody responses were then measured by virus neutralization testing against both the vaccine-related O BFS strain and the Jordan field strain O JORD. The headline result was that immunity against the homologous and heterologous type O strains was very similar overall, confirming cross-reactivity under field conditions rather than only in vitro matching studies. (frontiersin.org)
The species split is one of the more useful operational takeaways. Goats mounted better responses than sheep, and the paper says singly vaccinated goats maintained positivity above 70% against the Jordan field strain across measured timepoints. Sheep responded, too, but with lower neutralizing titers and lower positivity rates, especially over time. Booster vaccination improved both titers and positivity in both species, and the authors conclude that following the manufacturer’s schedule is necessary to achieve stronger, longer-lasting immunity, particularly in sheep. (frontiersin.org)
There’s also an important bridge here between lab prediction and field performance. The Frontiers authors say their results corroborate earlier vaccine-matching work suggesting that vaccines with a high concentration of O1 Campos antigen could cross-protect against O/ME-SA/PanAsia-2/ANT-10. Independent reference-laboratory reporting from the WOAH/FAO network had already flagged Jordan’s 2022-2023 post-vaccination monitoring as showing higher post-vaccination titers in goats than sheep, with boosters lifting both homologous and heterologous titers. In that sense, the new paper turns a technical surveillance signal into a more complete field dataset. (frontiersin.org)
Why it matters: For veterinarians and animal health officials, this is less about a single paper and more about how to run smarter FMD programs in mixed small-ruminant populations. First, it supports the use of post-vaccination monitoring as a decision tool, not a box-checking exercise, especially where strain turnover and cross-border risk are constant. Second, it suggests species-specific expectations may matter in campaign design: goats may seroconvert more strongly, while sheep may need especially consistent booster compliance and follow-up sampling. Third, the study reinforces a broader control principle from WOAH: vaccine choice, antigenic matching, coverage, and timing all matter together. (woah.org)
Industry reaction was limited in publicly available sources, but the broader institutional context points in the same direction. Jordan’s earlier campaign involved millions of doses and collaboration among the ministry, FAO-linked experts, and reference laboratories, underscoring how outbreak response, vaccine registration, and immunologic follow-up are being tied more closely together. That coordination is likely to matter as countries in the region continue working through the Progressive Control Pathway for FMD and confront multiple circulating serotypes. (foot-and-mouth.org)
What to watch: The next questions are whether these findings translate into longer-term field protection, whether booster strategies should differ by species, and how existing commercial vaccines perform against newer regional threats, including SAT2 lineages that have recently affected Jordan and neighboring countries. (rr-middleeast.woah.org)