Effect of Booster Vaccination with Inactivated Porcine Epidemic Diarrhea Virus on Neutralizing Antibody Response in Mammary Secretions

Abstract

Porcine epidemic diarrhea virus (PEDV) causes acute diarrhea, dehydration in pigs, and high mortality rates in piglets <3 weeks of age. Maternal immunity protects piglets, but information on vaccination before or after natural infection in endemically exposed sow herds is limited. Currently, the recovery goal in sow units infected with PEDV is to become fully naive again or use natural virus infection to develop immune gilts through a feedback program before introduction into the sow herd. Since neutralizing antibodies in the gut are critical for protection against enteric viral infections such as PEDV, we evaluated the effect of a conditionally licensed, adjuvanted inactivated PEDV vaccine on neutralizing antibody levels in milk and colostrum in both naive and previously naturally exposed sow herds. The results illustrate that intramuscular vaccination increased neutralizing antibody titers, and anti-PEDV IgA and IgG in milk and colostrum of sows that were previously infected. Thus, inactivated PEDV vaccines may provide increased protection to piglets nursing on previously infected sows against exposure to PEDV through increased delivery of lactogenic neutralizing antibodies to the enteric site of infection.

Host Factors Affecting Generation of Immunity Against Porcine Epidemic Diarrhea Virus in Pregnant and Lactating Swine and Passive Protection of Neonates

“…Using oral prime/parenteral booster vaccine approaches is also a promising strategy for generating protective lactogenic immunity. In a field study, PEDV seropositive sows given an IM injection of a conditionally licensed, adjuvanted inactivated PEDV vaccine had increased neutralizing antibody titers and anti-PEDV IgA and IgG antibodies in colostrum and milk [118]. However, because this study was on a commercial swine farm, piglets were not PEDV challenged.…”

Vaccination against coronaviruses in domestic animals

“…For example, neutralizing antibody titers in sows milk and colostrum increased fivefold in vaccinated sows with preexisting immunity. This antibody response was not however seen in naïve sows [35].…”

Swine enteric coronavirus disease: A review of 4 years with porcine epidemic diarrhoea virus and porcine deltacoronavirus in the United States and Canada

“…Subsequent to feedback administration or natural exposure, killed vaccines may effectively booster immunity and could provide an alternative for repeated virulent SECD exposure through the oral route. In Gillespie, Song, Inskeep, Stone, and Murtaugh (), PEDV‐neutralizing antibodies in milk and colostrum were significantly increased (approximately fivefold) in vaccinated sows with pre‐existing immunity compared to non‐vaccinated sows with pre‐existing immunity. However, this same response to an inactivated vaccine was not seen in naïve sows (Gillespie et al., ).…”

“…In Gillespie, Song, Inskeep, Stone, and Murtaugh (), PEDV‐neutralizing antibodies in milk and colostrum were significantly increased (approximately fivefold) in vaccinated sows with pre‐existing immunity compared to non‐vaccinated sows with pre‐existing immunity. However, this same response to an inactivated vaccine was not seen in naïve sows (Gillespie et al., ). Overall, use of feedback and vaccines in the field vary considerably in practice and a standardized procedure for stimulating and maintaining uniform SECD immunity throughout the herd is a much‐needed resource for the industry.…”