Inexpensive, oral bovine rotavirus vaccine effective for children
Three doses of a live, low-cost and heat-stable oral bovine rotavirus pentavalent vaccine could prevent cases of severe rotavirus gastroenteritis in 66.7% of children in Niger, according to a recent study published in The New England Journal of Medicine.
“Sub-Saharan Africa has the highest rate of death associated with rotavirus disease, but vaccination on a large scale presents challenges,” Sheila Isanaka, ScD, assistant professor of nutrition within the department of global health and population, T.H. Chan School of Public Health, Harvard University, and colleagues wrote. “Current prices of the two licensed vaccines [used by WHO] are probably unsustainable without external subsidies. In addition, the global supply of the vaccines is constrained, and unreliable transportation and storage systems make delivery of vaccines that require refrigeration difficult.”
For children younger than 5 years of age, rotavirus gastroenteritis is responsible for nearly 37% of global deaths. Since a significant number of these fatalities occur in sub-Saharan Africa, the researchers assessed the efficacy of a bovine rotavirus pentavalent vaccine (BRV-PV) manufactured by Serum Institute of India, and compared it with a placebo regarding resistance
Healthy infants were administered doses of the vaccine or a placebo at ages 6, 10 and 14 weeks, and Isanaka and colleagues used active and passive surveillance to monitor episodes of gastroenteritis. Those with gastroenteritis were graded on a Vesikari score, with higher scores given to those with more severe disease. The scores and outcomes of those who were administered the vaccine were compared with those who were given placebo to determine resistance against severe, lab-confirmed rotavirus gastroenteritis that scored 11 or greater on the scale.
Researchers included 3,508 children in this analysis. The vaccine demonstrated 66.7% efficacy, with 31 vaccinated and 87 unvaccinated children developing severe rotavirus gastroenteritis. In the intention-to-treat analysis, comparable results were found (69.1% vaccine efficacy). Between the vaccine and placebo groups, no significant difference was found concerning risk of adverse effects (68.7% in vaccine, 67.2% in placebo) or in the risk of serious adverse events (8.3% in vaccine, 9.1% in placebo).
Twenty-seven children who received the vaccine died compared with 22 children in the placebo group. No child involved had confirmed intussusception.
“In our trial, the vaccine efficacy in the intention-to-treat population, in which the vaccine administration schedule was more flexible than that in the per-protocol population, may more closely represent the efficacy under real-world conditions,” Isanaka and colleagues wrote. “The use of a reduced two-dose schedule with pentavalent vaccines has advantages with respect to cost and logistics, but evidence has been consistent with respect to the higher efficacy of a three-dose schedule.” — by Katherine Bortz
Disclosure: Monica M. McNeal reports grant support from Epicentre during the conduct of the study, and other support from Merck and GlaxoSmithKline outside the submitted work.