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Randomized controlled field trial to assess the immunogenicity and safety of rift valley fever clone 13 vaccine in livestock.

Njenga MK, Njagi L, Thumbi SM, Kahariri S, Githinji J, Omondi E, Baden A, Murithi M, Paweska J, Ithondeka PM, Ngeiywa KJ, Dungu B, Donadeu M, Munyua PM - PLoS Negl Trop Dis (2015)

Bottom Line: Although livestock vaccination is effective in preventing Rift Valley fever (RVF) epidemics, there are concerns about safety and effectiveness of the only commercially available RVF Smithburn vaccine.Vaccinated cattle (N = 42) did not develop IgM antibodies but 67% developed neutralizing IgG antibodies.There was no evidence of teratogenicity in vaccinated or placebo animals.

View Article: PubMed Central - PubMed

Affiliation: Division of Global Health Protection, United States Centers for Disease Control and Prevention-Kenya, Nairobi, Kenya; Paul G. Allen School for Global Animal Health, Washington State University, Pullman, Washington, United States of America.

ABSTRACT

Background: Although livestock vaccination is effective in preventing Rift Valley fever (RVF) epidemics, there are concerns about safety and effectiveness of the only commercially available RVF Smithburn vaccine. We conducted a randomized controlled field trial to evaluate the immunogenicity and safety of the new RVF Clone 13 vaccine, recently registered in South Africa.

Methods: In a blinded randomized controlled field trial, 404 animals (85 cattle, 168 sheep, and 151 goats) in three farms in Kenya were divided into three groups. Group A included males and non-pregnant females that were randomized and assigned to two groups; one vaccinated with RVF Clone 13 and the other given placebo. Groups B included animals in 1st half of pregnancy, and group C animals in 2nd half of pregnancy, which were also randomized and either vaccinated and given placebo. Animals were monitored for one year and virus antibodies titers assessed on days 14, 28, 56, 183 and 365.

Results: In vaccinated goats (N = 72), 72% developed anti-RVF virus IgM antibodies and 97% neutralizing IgG antibodies. In vaccinated sheep (N = 77), 84% developed IgM and 91% neutralizing IgG antibodies. Vaccinated cattle (N = 42) did not develop IgM antibodies but 67% developed neutralizing IgG antibodies. At day 14 post-vaccination, the odds of being seropositive for IgG in the vaccine group was 3.6 (95% CI, 1.5 - 9.2) in cattle, 90.0 (95% CI, 25.1 - 579.2) in goats, and 40.0 (95% CI, 16.5 - 110.5) in sheep. Abortion was observed in one vaccinated goat but histopathologic analysis did not indicate RVF virus infection. There was no evidence of teratogenicity in vaccinated or placebo animals.

Conclusions: The results suggest RVF Clone 13 vaccine is safe to use and has high (>90%) immunogenicity in sheep and goats but moderate (> 65%) immunogenicity in cattle.

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Proportion of sheep positive for anti-RVF antibodies following vaccination with RVF Clone 13 vaccine.Left panel (bottom) shows proportion of sheep showing IgG antibodies following vaccination within 14 to 366 days post-vaccination. The right panel (bottom) shows proportion of sheep that produced anti-RVF IgM antibodies. The top panel on the left and right are the placebo-treated animals.
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pntd.0003550.g004: Proportion of sheep positive for anti-RVF antibodies following vaccination with RVF Clone 13 vaccine.Left panel (bottom) shows proportion of sheep showing IgG antibodies following vaccination within 14 to 366 days post-vaccination. The right panel (bottom) shows proportion of sheep that produced anti-RVF IgM antibodies. The top panel on the left and right are the placebo-treated animals.

Mentions: Among the 3 study farms, a total of 404 animals were enrolled in the study; 151 goats, 85 cattle and 168 sheep. Of these, 170, 87, and 147 animals were enrolled in group A, B and C, respectively (Fig. 1). Vaccinated cattle (N = 42) did not develop any anti-RVF virus IgM antibodies but 67% developed anti-RVF virus IgG antibodies that were maintained in 43.6% of the animals through day 365 post-vaccination (Fig. 2). In vaccinated goats (N = 72), 72% developed IgM antibodies and 97% developed IgG antibodies that were maintained in all animals through day 365 (Fig. 3). In vaccinated sheep (N = 78), 84% developed IgM and 91% IgG antibodies that were maintained in 52.6% of the animals by day 365 (Fig. 4). At day 14, the odds of being seropositive for IgG in the vaccine group were significantly higher (P < 0.05) in vaccinated animals when compared to the placebo group, with an odds ratio of 4 in cattle, 90 in goats, and 40 in sheep (Table 1). The IgM antibody response between placebo and vaccinated groups in cattle and goats was statistically insignificant. However in sheep, IgM response was significantly higher in vaccinated as compared to placebo group of animals (Table 1).


Randomized controlled field trial to assess the immunogenicity and safety of rift valley fever clone 13 vaccine in livestock.

Njenga MK, Njagi L, Thumbi SM, Kahariri S, Githinji J, Omondi E, Baden A, Murithi M, Paweska J, Ithondeka PM, Ngeiywa KJ, Dungu B, Donadeu M, Munyua PM - PLoS Negl Trop Dis (2015)

Proportion of sheep positive for anti-RVF antibodies following vaccination with RVF Clone 13 vaccine.Left panel (bottom) shows proportion of sheep showing IgG antibodies following vaccination within 14 to 366 days post-vaccination. The right panel (bottom) shows proportion of sheep that produced anti-RVF IgM antibodies. The top panel on the left and right are the placebo-treated animals.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4355591&req=5

pntd.0003550.g004: Proportion of sheep positive for anti-RVF antibodies following vaccination with RVF Clone 13 vaccine.Left panel (bottom) shows proportion of sheep showing IgG antibodies following vaccination within 14 to 366 days post-vaccination. The right panel (bottom) shows proportion of sheep that produced anti-RVF IgM antibodies. The top panel on the left and right are the placebo-treated animals.
Mentions: Among the 3 study farms, a total of 404 animals were enrolled in the study; 151 goats, 85 cattle and 168 sheep. Of these, 170, 87, and 147 animals were enrolled in group A, B and C, respectively (Fig. 1). Vaccinated cattle (N = 42) did not develop any anti-RVF virus IgM antibodies but 67% developed anti-RVF virus IgG antibodies that were maintained in 43.6% of the animals through day 365 post-vaccination (Fig. 2). In vaccinated goats (N = 72), 72% developed IgM antibodies and 97% developed IgG antibodies that were maintained in all animals through day 365 (Fig. 3). In vaccinated sheep (N = 78), 84% developed IgM and 91% IgG antibodies that were maintained in 52.6% of the animals by day 365 (Fig. 4). At day 14, the odds of being seropositive for IgG in the vaccine group were significantly higher (P < 0.05) in vaccinated animals when compared to the placebo group, with an odds ratio of 4 in cattle, 90 in goats, and 40 in sheep (Table 1). The IgM antibody response between placebo and vaccinated groups in cattle and goats was statistically insignificant. However in sheep, IgM response was significantly higher in vaccinated as compared to placebo group of animals (Table 1).

Bottom Line: Although livestock vaccination is effective in preventing Rift Valley fever (RVF) epidemics, there are concerns about safety and effectiveness of the only commercially available RVF Smithburn vaccine.Vaccinated cattle (N = 42) did not develop IgM antibodies but 67% developed neutralizing IgG antibodies.There was no evidence of teratogenicity in vaccinated or placebo animals.

View Article: PubMed Central - PubMed

Affiliation: Division of Global Health Protection, United States Centers for Disease Control and Prevention-Kenya, Nairobi, Kenya; Paul G. Allen School for Global Animal Health, Washington State University, Pullman, Washington, United States of America.

ABSTRACT

Background: Although livestock vaccination is effective in preventing Rift Valley fever (RVF) epidemics, there are concerns about safety and effectiveness of the only commercially available RVF Smithburn vaccine. We conducted a randomized controlled field trial to evaluate the immunogenicity and safety of the new RVF Clone 13 vaccine, recently registered in South Africa.

Methods: In a blinded randomized controlled field trial, 404 animals (85 cattle, 168 sheep, and 151 goats) in three farms in Kenya were divided into three groups. Group A included males and non-pregnant females that were randomized and assigned to two groups; one vaccinated with RVF Clone 13 and the other given placebo. Groups B included animals in 1st half of pregnancy, and group C animals in 2nd half of pregnancy, which were also randomized and either vaccinated and given placebo. Animals were monitored for one year and virus antibodies titers assessed on days 14, 28, 56, 183 and 365.

Results: In vaccinated goats (N = 72), 72% developed anti-RVF virus IgM antibodies and 97% neutralizing IgG antibodies. In vaccinated sheep (N = 77), 84% developed IgM and 91% neutralizing IgG antibodies. Vaccinated cattle (N = 42) did not develop IgM antibodies but 67% developed neutralizing IgG antibodies. At day 14 post-vaccination, the odds of being seropositive for IgG in the vaccine group was 3.6 (95% CI, 1.5 - 9.2) in cattle, 90.0 (95% CI, 25.1 - 579.2) in goats, and 40.0 (95% CI, 16.5 - 110.5) in sheep. Abortion was observed in one vaccinated goat but histopathologic analysis did not indicate RVF virus infection. There was no evidence of teratogenicity in vaccinated or placebo animals.

Conclusions: The results suggest RVF Clone 13 vaccine is safe to use and has high (>90%) immunogenicity in sheep and goats but moderate (> 65%) immunogenicity in cattle.

Show MeSH
Related in: MedlinePlus