Meta-analysis of brucellosis vaccinology in natural hosts

Pereira

Transbounding Emerging Dis

et al. 2021

This systematic review and meta-analysis aimed to recalculate the efficacy of Brucella abortus S19 and RB51 vaccine strains and discuss the main variables associated with controlled trials to evaluate bovine brucellosis vaccine efficacy (VE). The most commonly used vaccine strain was S19, at a dose of 10 10 colony forming units (CFU), followed by RB51 at 10 10 CFU. The most commonly used challenge strain was B. abortus 2308, at a dose of 10 7 CFU, by the intraconjunctival route. Regarding the meta-analysis, trials were grouped according to the vaccine strain and dose to recalculate protection against abortion (four groups) or infection (five groups) using pooled risk ratio (RR) and VE. Regarding protection against abortion (n = 15 trials), the S19 vaccine at 10 9 CFU exhibited the highest protection rate (RR = 0.25, 95% confidence

Section: Discussionmentioning

confidence: 99%

Efficacy of Brucella abortus S19 and RB51 vaccine strains: A systematic review and meta‐analysis

Pereira

Transbounding Emerging Dis

et al. 2021

“…Albeit a systematic review has been published on the efficacy of brucellosis vaccines in natural hosts, in this study the efficacy was not recalculated according to the vaccine's target species, type of vaccine (attenuated, vector, DNA, etc.) and dose used (Carvalho et al, 2020). Moreover, from this study, it was also not possible to identify the trials used for meta-regression and the methodological quality employed was not optimal [inclusion / exclusion criteria and number of studies evaluated in each category (type of vaccine, host and dose) were unclear].…”

Section: Discussionmentioning

confidence: 96%

Efficacy of Brucella abortus S19 and RB51 vaccine strains: a systematic review and meta-analysis

Dorneles¹,

Oliveira²,

Pereira³

et al. 2021

Preprint

This systematic review and meta-analysis aimed to recalculate the efficacy of these two vaccine strains, and to discuss the main variables associated with controlled trials to evaluate bovine brucellosis vaccines efficacy. The most used vaccine strain was S19, at the dose of 10 colony forming units (CFU), followed by the vaccine strain RB51 at 10 CFU. The most used challenge strain was B. abortus 2308, at the dose of 10 CFU by intraconjunctival route. For the meta-analysis, trials were grouped according to the vaccine strain and dose to recalculate protection against abortion (four groups) or infection (five groups), using pooled risk ratio (RR) and vaccine efficacy (VE). For protection against abortion (n = 15 trials), S19 vaccine at 10 CFU exhibited the highest protection rate (RR = 0.25, 95% CI: 0.12 to 0.52; VE = 75.09%, 95% CI: 48.08 – 88.05), followed by RB51 10 (RR = 0.31, 95% CI: 0.16 to 0.61; VE = 69.25%, 95% CI: 39.48 – 84.38). For protection against infection (n = 23 trials), only two subgroups exhibited significant protection: S19 at 10 CFU (RR = 0.28, 95% CI: 0.14 to 0.55; VE = 72.03%, 95% CI: 57.70 – 81.50) and RB51 at 10 CFU dose (RR = 0.43, 95% CI: 0.22 to 0.84; VE = 57.05%, 95% CI: 30.90 – 73.30). In conclusion, our results suggest that the dose of 10 CFU for S19 and 10 CFU for RB51 are the most suitable for the prevention of abortion and infection caused by B. abortus.

“…Likewise, some recent meta-analyses of controlled experiments use publications that do not meet the requisites in Table 2 and apply elaborated statistics to data that are not amenable to quantification and statistical comparisons because of their qualitative character. Through this methodology, inactivated vaccines are superior to the live reference vaccines [ 144 ], a conclusion that disregards why these vaccines were discarded many years ago [ 35 , 145 ]. Other meta-analyses “suggest that the dose of 10 9 CFU for S19 and 10 10 CFU for RB51 are the most suitable for the prevention of abortion and infection …” and that the study “provides very relevant information for brucellosis control and eradication … that can drive adjustments in vaccination schemes and brucellosis control modelling” [ 146 ].…”

Section: The Conundrums Of Animal Brucellosismentioning

confidence: 99%

Facing the Human and Animal Brucellosis Conundrums: The Forgotten Lessons

2022

Brucellosis is a major zoonotic disease caused by Brucella species. Historically, the disease received over fifty names until it was recognized as a single entity, illustrating its protean manifestations and intricacies, traits that generated conundrums that have remained or re-emerged since they were first described. Here, we examine confusions concerning the clinical picture, serological diagnosis, and incidence of human brucellosis. We also discuss knowledge gaps and prevalent confusions about animal brucellosis, including brucellosis control strategies, the so-called confirmatory tests, and assumptions about the primary-binding assays and DNA detection methods. We describe how doubtfully characterized vaccines have failed to control brucellosis and emphasize how the requisites of controlled safety and protection experiments are generally overlooked. Finally, we briefly discuss the experience demonstrating that S19 remains the best cattle vaccine, while RB51 fails to validate its claimed properties (protection, differentiating infected and vaccinated animals (DIVA), and safety), offering a strong argument against its current widespread use. These conundrums show that knowledge dealing with brucellosis is lost, and previous experience is overlooked or misinterpreted, as illustrated in a significant number of misguided meta-analyses. In a global context of intensifying livestock breeding, such recurrent oversights threaten to increase the impact of brucellosis.