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Clinical trials of live oral rotavirus vaccines: the Finnish experience
1Department of Biomedical Sciences, University of Tampere, Finland.
Insights
Live oral rotavirus vaccines, including bovine and rhesus-derived strains, demonstrated significant protection against severe rotavirus diarrhea in young children. Optimal efficacy was observed when vaccines were administered before the epidemic season.
Area of Science:
- Pediatrics
- Vaccinology
- Infectious Diseases
Background:
- Rotavirus is a leading cause of severe diarrhea in young children globally.
- Live oral rotavirus vaccines have been developed to prevent rotavirus gastroenteritis.
- Previous studies have evaluated the efficacy of various rotavirus vaccine candidates.
Purpose of the Study:
- To evaluate the clinical efficacy of live oral rotavirus vaccines of bovine (RIT 4237) and rhesus (RRV-1) origin, as well as reassortants expressing human serotypes, in young children.
- To assess vaccine effectiveness over two rotavirus seasons and up to 2-3 years of age.
- To determine the impact of vaccination timing on vaccine efficacy.
Main Methods:
- Clinical trials conducted between 1983 and 1989 in Finland.
- Vaccination administered before the rotavirus epidemic season.
- Follow-up of vaccinees for up to 2-3 years, covering two epidemic seasons.
- Evaluation of protection rates against rotavirus-associated diarrhea and severe rotavirus disease.
Main Results:
- Protection rates against all rotavirus-associated diarrhea varied from 0% to 67%.
- Vaccine efficacy against severe rotavirus disease was higher, reaching up to 100%.
- All tested vaccines showed efficacy against non-rotavirus-associated diarrhea, indicating a broader clinical benefit.
- Candidate vaccines significantly reduced severe diarrhea in Finnish children aged 0-3 years.
Conclusions:
- Live oral rotavirus vaccines, including bovine and rhesus-derived strains and reassortants, are effective in reducing severe diarrhea in young children.
- The clinical benefit of these vaccines extends beyond rotavirus-specific protection.
- Administration in the autumn before the rotavirus epidemic season is recommended for optimal vaccine efficacy.
Abstract:
Live oral candidate rotavirus vaccines of bovine (RIT 4237) or rhesus (RRV-1) origin and reassortants of RRV-1 expressing human serotype 1 (DxRRV) or serotype 2 (DS1xRRV) VP7 protein were evaluated for clinical efficacy in young children in successive trials from 1983 to 1989. In each study, the vaccinations were given before a rotavirus epidemic season and the follow-up of vaccinees covered two rotavirus epidemic seasons lasting up to 2-3 years of age. Serotype 1 rotavirus was predominant in each season. Protection rates against all rotavirus-associated diarrhoea ranged from 0 to 67% but were higher, up to 100%, against more severe rotavirus disease. All tested vaccines also showed efficacy for diarrhoea not apparently associated with rotavirus; therefore the clinical benefit of the vaccinations was greater than could be deduced from efficacy rates for rotavirus-associated diarrhoea alone. Each of the candidate vaccines could significantly reduce severe diarrhoea in Finnish children in the first 2 to 3 years of life. For optimal efficacy, the vaccines should be administered in the autumn before the regular epidemic season of rotavirus.