Model predicts effectiveness of livestock vaccines

Scientists at The Roslin Institute have developed an epidemiological model to investigate the effectiveness of vaccines for preventing, mitigating or eliminating infectious diseases in livestock. When appropriately applied, even imperfect vaccines can prevent, eliminate or largely reduce the prevalence of viruses, the model shows.

The goal of effective vaccination is not only to protect individuals from disease, but to decrease the risk and severity of disease outbreaks, and ultimately eradicate the disease. The model shows that combining diverse vaccine properties may have a multiplicative effect and thus be considerably more effective. This could be used to prevent outbreaks if the vaccine is applied as a preventive measure, or to eliminate disease spread if applied during outbreaks.

The model was used to investigate the effectiveness of vaccines to combat Porcine reproductive and respiratory syndrome virus (PRRSV), although many of the principles apply to other viruses and pathogens.

Vaccines have mostly failed to stop the spread of PRRSV. The new model shows that the control or even elimination of the disease through vaccination may well be within reach, as long as the vaccine sufficiently speeds up recovery and reduces virus replication. The findings of the study are published in PLOS ONE.

A wiki-page aiming to provide scientists, veterinarians and the public with insight into the diverse factors influencing vaccine effectiveness in livestock has been developed by the scientists, as part of the European research project SAPHIR (Strengthening Animal Production and Health through Immune Response).

The wiki contains an interactive modelling app that illustrates how different types of vaccine and vaccination strategies may together influence how diseases spread.

Article: Bitsouni, V., Lycett, S., Opriessnig, T., Doeschl-Wilson, A. (2019). Predicting vaccine effectiveness in livestock populations: A theoretical framework applied to PRRS virus infections in pigs. PLoS ONE 14(8):e0220738, doi: 10.1371/journal.pone.0220738

Wiki: Vaccine Effectiveness In The Field

[SOURCE: The Roslin Institute]