Onset of and duration of immunity after vaccination with Porcilis PRRS

Onset of immunity

Seroconversion can be demonstrated two weeks after vaccination, with maximum titres against PRRSV infection obtained at approximately four weeks post-vaccination. However in some test systems it might take up to 7 weeks before seroconversion is detected (Gangl et al. 2004).

The timing of all challenges in the various experiments were carried out at four weeks post-vaccination. At the time of challenge all piglets were completely protected.

Duration of immunity

Experiments have demonstrated that, after vaccination at 5 to 6 weeks of age, piglets are protected against PRRSV infection throughout the finishing period. The level of protection after this period was still maximal, and no viraemia was detected after challenge. Protection probably extends over a longer period than that tested.

See the results of the trials in the graphs below.