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Field trial of rhesus rotavirus vaccine in infants
C Christy1, H P Madore, M E Pichichero
1Department of Pediatric, University of Rochester School of Medicine and Dentistry, NY.
Insights
The rhesus rotavirus vaccine (RRV) showed mild side effects and good immunogenicity in infants. However, it did not reduce rotavirus illness, possibly due to serotype mismatch, suggesting a need for polyvalent rotavirus vaccines.
Area of Science:
- Pediatrics
- Vaccinology
- Virology
Background:
- Rotavirus is a leading cause of severe gastroenteritis in infants globally.
- Development of effective rotavirus vaccines is crucial for public health.
- Rhesus rotavirus vaccine (RRV) was investigated for its efficacy and safety.
Purpose of the Study:
- To evaluate the safety and immunogenicity of an orally administered rhesus rotavirus vaccine (RRV) in infants.
- To assess the efficacy of RRV in preventing rotavirus-associated illnesses.
- To identify factors influencing vaccine response, such as breastfeeding status and circulating rotavirus serotypes.
Main Methods:
- A placebo-controlled study involving 176 infants aged 2 to 4 months.
- Infants received either 10(4) plaque-forming units of RRV or a placebo.
- Safety was assessed by monitoring adverse events, including febrile reactions and loose stools.
- Immunogenicity was determined by measuring serum neutralizing antibody responses.
- Rotavirus-associated illnesses and circulating serotypes were monitored.
Main Results:
- RRV was well-tolerated but mildly reactogenic, with increased rates of mild fever and loose stools compared to placebo.
- The vaccine induced a significant seroresponse (≥4-fold rise in antibodies) in 67% of recipients.
- Breastfed infants showed a lower seroresponse rate compared to non-breastfed infants.
- Despite good immunogenicity, the overall incidence of rotavirus-associated illnesses was similar between vaccine and placebo groups.
- Circulating rotaviruses were predominantly serotype 1, while RRV is serotype 3, suggesting a potential serotype mismatch.
Conclusions:
- Orally administered RRV is safe and immunogenic in infants but did not demonstrate efficacy in preventing rotavirus illness in this study population.
- The lack of efficacy may be attributed to a mismatch between the vaccine serotype (3) and the predominant circulating wild-type serotype (1).
- These findings highlight the importance of considering circulating rotavirus serotypes and suggest that a polyvalent rotavirus vaccine may be necessary for broad protection.
Abstract:
Orally administered rhesus rotavirus vaccine (RRV) was evaluated in a placebo-controlled study in 176 infants (ages 2 to 4 months). Eighty-eight infants received a dose of 10(4) plaque-forming units of the vaccine, and 88 received the placebo. RRV was well-tolerated but mildly reactogenic in the 10 days after vaccination. There were mild febrile reactions (greater than or equal to 38 degrees C rectally) in 40% of the vaccinees and in 16% of the placebo recipients (P = 0.001). More of the vaccinees had loose stools than did the placebo recipients (P less than 0.05). RRV was immunogenic and induced a 4-fold or greater rise in serum neutralizing antibody responses in 67% of the vaccinees; however, breast-fed infants were less likely to develop a seroresponse than infants who were not breast-fed. Despite the good immunogenicity of RRV the overall incidence of rotavirus-associated illnesses was similar between the vaccine and placebo recipients. The failure of RRV in Rochester may be related to the fact that the circulating rotaviruses were predominantly serotype 1 and RRV is a serotype 3 rotavirus. Because the serotypes of rotavirus that predominate may vary from year to year, a polyvalent preparation may be necessary to provide effective vaccination against rotaviruses.