Vaccination of influenza a virus decreases transmission rates in pigs

Romagosa, Anna; Allerson, Matt; Gramer, Marie; Joo, Han Soo; Deen, John; Detmer, Susan; Torremorell, Montserrat

In the NV group, all contact pigs became infected and R 0 (95% confidence interval) was estimated at 10.66 (6.57-16.46). In contrast, the estimate of R was 1.00 (0.39-2.09) in the HE group, and 0 in the HO group. A Before contact (-2 dpc) and at necropsy (i.e. + 7 dpc for the control group/+14 dpc for the vaccinated groups). a,b Statistically significant differences (p < 0.05). statistically significant reduction in R value was observed in the vaccinated groups (p < 0.05). The difference in transmission rate (β) was also statistically significant between the NV and HE groups (p < 0.0001). Transmission in the HO vaccinated pigs could not be detected in any of the replicates. Transmission in the HE group was observed in all replicates and although R was above 1 in two of the four replicates, R was not statistically significant below 1. However, there were statistically significant differences between HE transmission rate β replicates with differences observed between replicates 1, 2, 3 versus 4 (p < 0.001).