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Encouraging results from a rotavirus vaccine trial in Latin American infants

Lancet

Two doses of an oral live attenuated human rotavirus vaccine are effective against severe rotavirus gastroenteritis for up to two years when given to Latin American infants during the first two years of life. These are the conclusions of the authors of an Article in this week's edition of The Lancet.

Professor Miguel O'Ryan, Institute of Biomedical Sciences, Faculty of Medicine, University of Chile, and colleagues did a double-blind, placebo-controlled phase III study of 15 183 healthy infants from ten Latin American countries. The infants were randomly assigned to receive two oral doses of RIX4414 or placebo. The endpoints measured were vaccine efficacies from 2 weeks after dose two until 1 year of age, during the second year, and for the combined two year period from 2 weeks after dose two until about 24 months of age.

Fewer cases of severe rotavirus gastroenteritis were recorded for the combined 2-year period in the vaccine group (32 [0·4%] of 7205) than in the placebo group (161 [2·3%] of 7081); vaccine efficacy was 80·5-82·1% against the wild-type G1 rotavirus strain, 77·5% against pooled non-G1 strains, and 80·5% against pooled non-G1 P[8] strains. Vaccine efficacy for hospital admission for rotavirus gastroenteritis was 83·0% and for admission for diarrhoea of any cause was 39·3%. Intussusception (invagination of one part of the intestine into the other) was not reported during the second year of follow-up.

The investigators conclude: "Inclusion of this vaccine in routine paediatric immunisation schedules can be expected to greatly reduce the burden of rotavirus disease worldwide."

In an accompanying Comment, Professor Keith Grimwood, Queensland Paediatric Infectious Disease Laboratory, Discipline of Paediatrics and Child Health, Royal Children's Hospital and University of Queensland, Brisbane, Australia, says: "WHO is awaiting efficacy data from low-income countries of Africa and Asia, where much greater strain diversity exists and where 413 000 rotavirus deaths occur every year compared with 15 000 in Latin America and 200 in Europe."

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Professor Miguel O'Ryan, Institute of Biomedical Sciences, Faculty of Medicine, University of Chile. T) +56 27355855

Comment Professor Keith Grimwood, Queensland Paediatric Infectious Disease Laboratory, Discipline of Paediatrics and Child Health, Royal Children's Hospital and University of Queensland, Brisbane, Australia. T) +61 7363 65558

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