The Porcine Circovirus Type 2 Bivalent Vaccine is now available—providing dual protection with a single dose, making pig farming even more hassle-free!

On November 6, 2018, Luoyang Huizhong Biotechnology Co., Ltd. (a wholly owned subsidiary of Placor Bioengineering Co., Ltd.), held a product launch event in Luoyang for its bivalent inactivated vaccine against porcine circovirus type 2 and Mycoplasma hyopneumoniae, which was developed over eight years with the support of the National Engineering Research Center for Veterinary Pharmaceuticals.

“The bivalent inactivated vaccine against Porcine Circovirus Type 2 and Mycoplasma hyopneumoniae” is a major scientific and technological achievement of Huizhong Biotechnology Co., Ltd., developed under the company’s business philosophy of “upright and prudent management” and its development strategy of “innovation shapes the future.” Leveraging the National Engineering Research Center for Veterinary Drugs as its technical platform, the product boasts independent intellectual property rights and has obtained a national registration certificate for new veterinary drugs. This breakthrough represents another significant milestone, following Huizhong Biotechnology’s adjuvanted inactivated vaccine against Porcine Circovirus Type 2 (SH strain II), achieved through sustained innovation and practical application.

In recent years, as China’s agricultural and pastoral industrialization reforms have deepened, the sustainable development of the country’s livestock sector has been strongly promoted, leading to substantial increases in both the diversity and numbers of livestock and poultry breeds. At the same time, the variety and incidence of livestock and poultry diseases have risen markedly. In clinical practice, mixed infections are common, with co-infection by porcine circovirus type 2 and Mycoplasma hyopneumoniae being particularly prevalent. Consequently, combination vaccines capable of preventing multiple diseases have become a major trend in the development of veterinary biologics and an urgently needed product for livestock producers. Although well‑established monovalent vaccines are available for each of these pathogens, their numerous formulations and complex immunization schedules pose challenges. A combined vaccine targeting porcine circovirus type 2 and Mycoplasma hyopneumoniae can address many of the limitations associated with using separate vaccines, delivering dual protection in a single dose while saving time and effort.

The “Porcine Circovirus Type 2 and Mycoplasma hyopneumoniae Bivalent Inactivated Vaccine” launched by Huizhong Bio this time boasts fully independent intellectual property rights, having been the first to complete product development and obtain a new veterinary drug certificate. A proprietary water-based adjuvant, combined with advanced vaccine‑production technology, ensures the quality of the bivalent formulation, enabling simultaneous protection against two pathogens while effectively mitigating risks associated with incompatibility between adjuvants and antigens, as well as poor stability and uniformity that can arise when single‑component vaccines are mixed.

1. Domestically isolated strains are better suited to Chinese pig farms: For Mycoplasma hyopneumoniae, the domestically isolated epidemic strain HN0613 is used. Nucleotide sequence analysis of the R1 region of the P97 gene reveals that its homology with domestic isolates is significantly higher than that with foreign strains. Both laboratory challenge studies and field use have demonstrated its excellent immunogenicity and protective efficacy, providing more comprehensive protection and greater suitability for Chinese pig farms.

2. Antigen purification without interference, resolving compatibility challenges: By optimizing the culture medium formulation and fermentation parameters, we overcame the technical hurdles associated with high‑density Mycoplasma fermentation, achieving a stable cell density of 5.0 × 10^9 CCU/mL. Employing tangential flow ultrafiltration and other purification processes, we completely removed porcine circovirus type 2 antibodies from the porcine serum used in Mycoplasma cultivation, attaining a contaminant protein removal rate of 99% and thereby preventing any interference with the immune response against circovirus, thus addressing the compatibility issue between the two antigens. For the circovirus antigen, we utilized PK15‑B1 susceptible clone cells, yielding a titers ≥ 1.0 × 10^7.0 TCID50 per dose. Through tangential flow ultrafiltration and related purification steps, the contaminant protein removal efficiency exceeded 99%, and the antibody titers in post‑vaccination pig sera were comparable to those of imported vaccines.

3. A specially formulated adjuvant is优选, enabling simultaneous use with two antigens: The adjuvant in this product (Freemix™‑Gel Adjuvant) is prepared as nanospheres using a colloidal high‑molecular‑weight crosslinked copolymer, with a positively charged surface. Through electrostatic adsorption, it effectively binds the negatively charged PCV2 and mycoplasma antigens, forming an antigen–adjuvant complex that is readily recognized and processed by immune cells. Over 90% of the nanoparticles have diameters below 1,000 nm, facilitating rapid recognition by antigen‑presenting cells, thereby initiating and activating a robust immune response and ensuring swift protective immunity following vaccination. Moreover, the nanoparticles feature a porous, network‑like internal structure that encapsulates both antigens, enabling sustained, slow release and providing an immunity duration exceeding four months.