Obstetrics & Gynecology · Medical Literature
Safety and reproductive performance in sows after vaccination: a randomized controlled trial.
Abstract
Although reproductive vaccines are essential in swine herd health programs, evidence on their safety across different physiological stages remains limited. This study evaluated the clinical and reproductive safety of Porcilis® EPL in sows and gilts under commercial field conditions. In a randomized, blinded, controlled trial, 200 females were allocated to treated or control groups within five physiological categories, of which 190 completed the study. Sows received a single dose and gilts a two-dose protocol. Clinical parameters (body condition, rectal temperature, general health, feed intake) and injection-site reactions were monitored for 14 days post-vaccination. Reproductive outcomes, including conception, litter size, stillbirths, mummification, and neonatal viability, were recorded. PCR testing for PCV2, PCV3, and PPV was performed on non-viable piglets. The vaccine was well tolerated, with no systemic adverse reactions and only mild, self-limiting injection-site swellings in some treated females. Body condition and temperature profiles remained within physiological limits. Reproductive performance did not differ between groups (p > 0.05). Pathogen detection frequencies were similar across treatments, indicating that vaccination did not measurably alter fetal susceptibility to endemic PCV2, PCV3, or PPV. Porcilis® EPL showed excellent clinical and reproductive safety when administered during different physiological stages in sows and gilts. The vaccine did not affect fertility, gestational outcomes, or perinatal survival and did not measurably alter pathogen detection under field conditions with natural pathogen exposure, supporting its safe integration into breeding herd vaccination programs. PCR detection of PCV2, PCV3, and PPV was included as an exploratory epidemiological assessment to distinguish vaccine-specific effects from endemic pathogen circulation. No differences were observed between groups, supporting that Porcilis® EPL did not influence susceptibility to non-target pathogens.
Clinical relevance
Although reproductive vaccines are a cornerstone of swine herd health management, robust controlled safety data across distinct physiological stages (e.g., early gestation, late gestation, lactation, pre-breeding gilts) have been lacking, creating uncertainty for herd veterinarians advising on optimal vaccination timing. This randomized controlled trial addresses that evidence gap by evaluating both clinical and reproductive safety of Porcilis® EPL under commercial field conditions in a mixed population of sows and gilts. Given the significant economic and welfare consequences of vaccine-associated reproductive failure in breeding herds, these findings are directly relevant to swine practitioners and production veterinarians managing large commercial operations.
Key findings
1. A total of 200 females were randomized to treated or control groups across five physiological categories, with 190 completing the study, providing adequate power for safety assessment across reproductive stages. 2. No systemic adverse reactions were observed in any vaccinated animal; local injection-site reactions were limited to mild, self-limiting swellings in a subset of treated females, indicating a favorable local tolerability profile. 3. Body condition scores and rectal temperature profiles remained within physiological limits throughout the 14-day post-vaccination monitoring period in all treated animals, with no clinically significant deviations reported. 4. All reproductive outcomes assessed — including conception rate, total litter size, stillbirth rate, mummification rate, and neonatal viability — did not differ significantly between vaccinated and control groups (p > 0.05 for all parameters). 5. PCR detection frequencies for PCV2, PCV3, and PPV in non-viable piglets were similar between treatment and control groups, indicating that vaccination did not measurably alter fetal or neonatal susceptibility to these endemic pathogens. 6. The two-dose gilt protocol and single-dose sow protocol were both well tolerated, suggesting that dosing regimen differences based on prior immune experience did not differentially affect safety outcomes across physiological categories.
Practice implications
Porcilis® EPL can be confidently integrated into breeding herd vaccination programs across multiple physiological stages — including gestation and lactation — without expectation of adverse effects on fertility, litter size, stillbirth rates, or perinatal survival, supporting flexible scheduling aligned with herd management cycles. Clinicians should apply the approved species-specific dosing protocol: a single dose for previously exposed sows and a two-dose priming series for gilts, with post-injection monitoring for local swelling being sufficient given the absence of systemic reactions. The finding that pathogen detection rates for PCV2, PCV3, and PPV were unaffected by vaccination provides additional reassurance that the vaccine does not alter susceptibility to co-circulating non-target pathogens, though herd-level biosecurity and pathogen surveillance should continue independently of vaccination status.