Mounting evidence shows that PCV2d is now the predominant genotype circulating in U.S. swine herds and globally, and it is responsible for the majority of clinical PCVAD cases. This shift reinforces the importance of optimizing protection based on the genotype pigs are most likely to encounter in today’s production systems.^1-3

Diagnostic data from the Iowa State University Veterinary Diagnostic Laboratory and global surveillance efforts confirm a steady shift in PCV2 genotype prevalence over time, with PCV2d now accounting for approximately 75% of U.S. diagnostic cases. Similar trends have been reported internationally, suggesting this shift is not temporary or regionally isolated.^1-2

Beyond surveillance data, new research has strengthened the link between PCV2d and clinical disease expression. In a multistate investigation evaluating oral fluid surveillance alongside confirmed PCVAD cases, PCV2d was detected in nearly 77% of PCV2-positive production sites. More notably, sequencing of confirmed PCVAD cases revealed that over 82% were associated with PCV2d, compared to much lower detection rates for other genotypes. These findings suggest that PCV2d is not only widespread, but also a key driver of PCVAD, regardless of geography or production system.³

Disease rarely occurs in isolation

Complicating PCV2 control further is the reality that pigs rarely face a single pathogen challenge at a time. Coinfections — particularly with porcine reproductive and respiratory syndrome virus (PRRSV) — are common, and can significantly amplify clinical disease, mortality and performance losses.^4–5

A controlled challenge study evaluating pigs exposed to both PCV2d and PRRSV provides insight into how vaccine genotype influences outcomes under complex disease pressure. In this study, pigs vaccinated with a PCV2d-based vaccine experienced the lowest mortality, fewer treatments and reduced viral replication compared to pigs vaccinated with a PCV2a-based vaccine, with both groups outperforming non-vaccinated controls.^4–5

These results indicate that homologous protection — vaccinating against the genotype pigs are most likely to encounter — can help optimize immune response, particularly amid a coinfection challenge.

Take the guesswork out of your PCV2 vaccination protocol

Taken together, research findings, surveillance data and clinical‑case investigations point to a consistent conclusion: PCV2d defines today’s PCV2 risk landscape — and vaccination strategies should reflect that reality.

PCV2a-based vaccines have historically served the industry well and played a major role in controlling disease. However, as genotype prevalence has changed, questions have emerged about whether optimizing immunity through genotype-matched protection could offer added benefits under today’s disease pressure.

INGELVAC CIRCOFLEX® AD vaccine combines both PCV2a and PCV2d antigens in one single dose, taking the guesswork out of PCV2 protection. Built on the trusted foundation of the INGELVAC CIRCOFLEX® vaccine, this vaccine:

• Delivers robust protection, as demonstrated through significant reductions in viremia, fecal shedding, and lymphoid depletion and colonization.⁶
• Can be administered to pigs as young as 2–3 weeks of age.
• Uses the same proven-safe IMPRANFLEX® adjuvant platform producers already trust.

Talk to your Boehringer Ingelheim representative or click here to learn how INGELVAC CIRCOFLEX® AD can help simplify PCV2 protection while addressing today’s most relevant genotype threats with broader, optimized protection.

References

¹ Pineyro P, Ribeiro Braga E, Zeller MA, Gauger P C, Trevisan G, Leite F. Genotypic diversity of porcine circovirus 2 (PCV2) on a global scale and within the United States, in Proceedings. Leman Conf 2025;129–130. 

² Franzo G, Tucciarone CM, Legnardi M, Drigo M, Segalés J. An updated phylogeography and population dynamics of porcine circovirus 2 genotypes: Are they reaching an equilibrium? Front Microbiol 2024;15:1500498. doi:10.3389/fmicb.2024.1500498.

³ Rodriguez-Torrado A, Morgan J, Waddell J, Pineyro P, Leite F. Investigation of porcine circovirus type 2 genotype d in U.S. swine populations and its association with clinical disease, in Proceedings. AASV Annu Meet 2026.

⁴ Kroeger M, Fano E, Sponheim A, Schwartz K, Leite F, Gomez-Duran O, Lecznieski L, Piñeyro P. Assessment of homologous and heterologous PCV2 vaccine efficacy in a PCV2d/PRRSV co-challenge model. Vaccine 2025;60:127303.

⁵ Cezar G, Leite F, Fano E, Phillips R, Waddell J, Dion K, Magalhães E, Trevisan G, Silva G, & Linhares D. Assessing the detection and interaction of Lawsonia intracellularis and porcine circovirus 2 in low and high performance wean-to-finish pig groups in different porcine reproductive and respiratory syndrome virus detection scenarios. Front Vet Sci 2025;11, 1535803. doi:10.3389/fvets.2024.1535803.

⁶ Kaiser T, Jarrett A, Escoe S, Hinds M, Leite F. Efficacy of a novel vaccine containing both PCV2a and PCV2d antigens, in Proceedings. Leman Conf 2025;65–66.

INGELVAC CIRCOFLEX® and IMPRANFLEX® are registered trademarks of Boehringer Ingelheim Vetmedica GmbH, used under license. ©2026 Boehringer Ingelheim Animal Health USA Inc., Duluth, GA. All rights reserved. US-SWN-0002-2026