One-dose PCV2 vaccine matches two-dose regimen

A recent study shows that a single dose of FLEXcombo® vaccine is as efficacious as a two-dose protocol.
calendar icon 3 January 2019
clock icon 4 minute read

More is not always better when it comes to vaccinating swine herds to protect against porcine circovirus Type 2 (PCV2). A recent study shows that a single dose of FLEXcombo® vaccine, which protects against PCV2 and Mycoplasma hyopneumoniae, is as efficacious as a two-dose protocol, [1] and it reduces pig handling and stress, as well as labour and time.

PCV2 is a slow-mutating DNA virus, with the latest mutation, labelled PCV2d, documented in 2012. Since this discovery, researchers have conducted several studies and confirmed that existing PCV2 vaccines are effective against this strain. [2]

One dose versus two

Our Boehringer Ingelheim (BI) researchers conducted a head-to-head field comparison to determine if there was a difference in efficacy between a single dose of FLEXCOMBO vaccine and a two-dose protocol of a competitor’s vaccine. The study measured average daily weight gain (ADWG), as well as mortality and culling rates following field exposure to PCV2d, and noted any injection-site swelling.

In the study, pigs were about 21 days at weaning, and randomly assigned to one of three groups. The T1 group received a single dose of FLEXCOMBO vaccine on day 1. The T2 group received first and second doses of the competitor’s vaccine on days 1 and 22, respectively. Weights were measured on days 0, 71 and 153.

Comparable performance

Pigs in both vaccinated groups showed no clinical signs of porcine circovirus–associated disease. Study data showed no significant differences in ADWG, mortality or culling between the single- and two-dose treatment groups. The only difference observed was that pigs receiving two vaccine doses had significantly greater injection site swelling (33 percent) versus the one-dose protocol (0 percent).

Study Results – Weight

a,b Means with different superscripts indicate difference at P ≤ 0.05 (Student’s t).

Study Results – Average Daily Gain

a,b Means with different superscripts indicate difference at P≤0.05 (Student’s t).

Study Results – Percent Mortality

a,b Means with different superscripts indicate difference at P ≤ 0.05.

Study Results – Percent Cull

a,b Means with different superscripts indicate difference at P ≤ 0.05.
*Cull rates based on pigs weighing less than 225 pounds on day 153.

Study Results – Percent Injection-Site Swelling

a,b Means differ (Pearson Chi-square).

FLEXCOMBO is used successfully in many top swine operations across the United States, and has been proven efficacious in at least 23 challenge studies against all known PCV2 isolates.3 Its ImpranFLEX® adjuvant technology is specifically designed for a one-dose, low-volume vaccine that delivers fast onset of immunity and reliable protection all the way to slaughter.


[1] Fano E, Schaefer N, Schmaling E, et al. Comparison of efficacy between two PCV2 vaccination protocols under PCV2d field exposure. Paper presented at the AASV Annual Meeting; February 2017; Denver, Colorado.

[2] Opriessnig T, Gerber PF, Xiao CT, et al. Commercial PCV2a-based vaccines are effective in protecting naturally PCV2b-infected finisher pigs against experimental challenge with a 2012 mutant PCV2. Vaccine 2014;32(34):4342–4348.

[3] Payne B, Jacobs A, Dvorak C, et al. PCV2 vaccine cross-protection: Identification of sequences in successfully vaccinated field cases, in Proceedings. AASV Annual Meeting 2016;202–206.

FLEX Family is a trademark and FLEXcombo and ImpranFLEX are registered trademarks of Boehringer Ingelheim Vetmedica GmbH. ©2017 Boehringer Ingelheim Vetmedica, Inc.

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