On 5 December 2019 the European Medicines Agency issued advice on the use of live attenuated PRRSV vaccines in pigs. The vaccines concerned are authorised and available throughout the EU, including in Ireland. The issue is the known recombination between strains of PRRS virus, that has been associated with clinical signs of disease in PRRS-naïve herds in Denmark in recent months.
The pig vaccines that contain live attenuated PRRSV and which are authorised for use in Ireland are as follows:
- Suvaxyn PRRS MLV lyophylisate and solvent for suspension for injection for pigs (EU/2/17/215/001-003); Zoetis Belgium SA.
- UNISTRAIN PRRS lyophilisate and solvent for suspension for injection for pigs (VPA 10846/013/001); Laboratorios Hipra S.A.
- Porcilis PRRS lyophilisate and solvent for suspension for injection for pigs (VPA 10996/128/001); Intervet Ireland Limited.
- ReproCyc PRRS EU lyophilisate and solvent for suspension for injection for pigs (VPA 10454/012/001); Boehringer Ingelheim Vetmedica GmbH.
- Ingelvac PRRSFLEX EU lyophilisate and solvent for suspension for injection for pigs (VPA 10454/008/001); Boehringer Ingelheim Vetmedica GmbH.
Problem Or Issue:
Recombination between strains of PRRS virus, including live type 1 PRRSV vaccine strains, is a known phenomenon that has been reported previously in the scientific literature. It has recently been reported in Denmark, where it has been associated with clinical signs of disease in PRRS-naïve herds in recent months. Following initial consideration of the matter, the EMA’s Committee for Veterinary Medicinal Products (CVMP) has made the following recommendations:
- In order to limit the potential risk of recombination between vaccine strains, the simultaneous or consecutive use of different live attenuated PRRSV vaccines should be avoided as much as possible while continuing to protect animal health.
- Increased monitoring of any suspected adverse event relating to clinical signs of PRRS, including the occurrence of relevant clinical signs of the disease in vaccinated herds, is recommended. Any suspected adverse event should be reported to the national competent authority for veterinary medicines or the marketing authorisation holder. Clinical signs of PRRS include reduced fertility, increased rate of abortions, reduced appetite, increased piglet mortality and respiratory distress
Actions To Be Taken:
Veterinary practitioners should, where possible, avoid using live attenuated PRRSV vaccines from different manufacturers in animals in the same herd.
Veterinary practitioners should monitor for clinical signs of PRRS in vaccinated pig farms. Any suspected adverse events should be reported to the HPRA or the marketing authorisation holder for the vaccines involved