New insights about vaccine effectiveness: Impact of attenuated PRRS-strain vaccination on heterologous strain transmission
| Autor: | Jiexiong Xie, Andrea Doeschl-Wilson, Ivan Trus, Richard I. Bailey, Maria Belén Barrio, Margo Chase-Topping, Christopher Pooley, Helen Brown, Sylvie Gueguen, Kelly Rediger, Hans Nauwynck, Vasiliki Bitsouni, Caroline Bonckaert |
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| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Swine
030231 tropical medicine Population Basic Reproduction Number Porcine Reproductive and Respiratory Syndrome Heterologous Biology Antibodies Viral Vaccines Attenuated Porcine reproductive and respiratory syndrome Bayesian Virus Serology law.invention 03 medical and health sciences 0302 clinical medicine law Animals Transmission Porcine respiratory and reproductive syndrome virus 030212 general & internal medicine Viremia education education.field_of_study R0 General Veterinary General Immunology and Microbiology Vaccination Public Health Environmental and Occupational Health Bayes Theorem Viral Vaccines Virology Virus Shedding Infectious Diseases Transmission (mechanics) Molecular Medicine Viral load Horizontal transmission |
| Zdroj: | Chase-Topping, M, Xie, J, Pooley, C, Trus, I, Bonckaert, C, Rediger, K, Bailey, R, Brown, H, Bitsouni, V, Barrio, M B, Gueguen, S, Nauwynck, H & Wilson, A 2020, ' New insights about vaccine effectiveness: Impact of attenuated PRRS-strain vaccination on heterologous strain transmission ', Vaccine . https://doi.org/10.1016/j.vaccine.2020.02.015 |
| Popis: | Vaccination is the main tool for controlling infectious diseases in livestock. Yet current vaccines only provide partial protection raising concerns about vaccine effectiveness in the field.Two successive transmission trials were performed involving 52 pigs to evaluate the effectiveness of a Porcine Reproductive and Respiratory Syndrome (PRRS) vaccinal strain candidate against horizontal transmission of a virulent heterologous strain. PRRS virus, above the specified limit of detection, was observed in serum and nasal secretions for all but one pig (the exception only tested positive for serum), indicating that vaccination did not protect pigs from becoming infected and shedding the heterologous strain. However, vaccination delayed the onset of viraemia, reduced the duration of shedding and significantly decreased viral load throughout infection. Serum antibody profiles indicated that 4 out of 13 (31%) vaccinates in one trial had no serological response (NSR).A Bayesian epidemiological model was fitted to the data to assess the impact of vaccination and presence of NSRs on PRRS virus transmission dynamics. Despite little evidence for reduction in the transmission rate, vaccinated animals were on average slower to become infectious, experienced a shorter infectious period and recovered faster. The overall PRRSV transmission potential, represented by the reproductive ratio R0 was lower for the vaccinated animals, although there was substantial overlap in the credibility intervals for both groups. Model selection suggests that transmission parameters of vaccinated pigs with NSR were more similar to those of unvaccinated animals. The presence of NSRs in a population, however, seemed to only marginally affect the transmission dynamics.The results suggest that even when vaccination can’t prevent infection, it can still have beneficial impacts on the transmission dynamics and contribute to reducing a herd’s R0. However, biosecurity and other measures need to be considered to decrease contact rates and lower R0 below 1. |
| Databáze: | OpenAIRE |
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