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Factors affecting antibody response of newborns to repeated administrations of the rotavirus vaccine RIT 4237
S Cadranel1, S Zeglache, T Jonckheer
1Department of Virology, University of Brussels, Belgium.
Insights
This study on the RIT 4237 rotavirus vaccine in newborns found that maternal antibodies, not gastric acidity, reduced vaccine effectiveness. A multiple-dose schedule is recommended for optimal immune response.
Area of Science:
- Pediatrics
- Immunology
- Vaccinology
Background:
- Rotavirus is a leading cause of severe diarrheal disease in infants globally.
- Oral live attenuated rotavirus vaccines require successful replication (vaccine
- take rate
- ) for immunogenicity.
- Maternal antibodies and gastric acidity are potential factors influencing vaccine take rate.
Purpose of the Study:
- To assess the safety and immunogenicity of repeated doses of RIT 4237, an oral live attenuated rotavirus vaccine.
- To investigate the impact of gastric acidity and maternal antibodies on the vaccine "take rate" in newborns.
- To determine the optimal dosing schedule for RIT 4237.
Main Methods:
- A prospective study involving 57 newborns receiving RIT 4237 orally on days 1, 30, and 60 of life.
- Safety assessed via adverse reaction monitoring.
- Immunogenicity evaluated by serum antibody neutralization assays pre- and post-vaccination.
- Gastric pH measured at vaccination times.
Main Results:
- No adverse reactions were reported.
- Cumulative vaccine response after three doses was 63.9% (23/36).
- Lower pre-vaccination antibody titers in responders suggested maternal antibody interference.
- No significant difference in gastric pH between responders and non-responders was observed.
Conclusions:
- Maternal antibodies, not gastric acidity, significantly interfere with RIT 4237 vaccine efficacy in newborns.
- A multiple-dose vaccination schedule is necessary to achieve optimal immune responses.
- Further research into strategies to overcome maternal antibody interference is warranted.
Abstract:
The safety and immunogenicity of repeated doses of RIT 4237, an oral live attenuated rotavirus vaccine of bovine origin, as well as the influence of gastric acidity and maternal antibodies on the vaccine "take rate" were studied in newborns. The vaccine was given orally on the first day of life, at 1 month, and at 2 months of age. Fifty-seven newborns entered the study but only 36 completed the trial. No adverse reaction was observed after vaccination. Immune responses were evaluated by titrating pre- and postvaccination serum antibodies to RIT 4237 by a neutralization technique. Eight of 43 (18.6%) tested infants responded to the first dose of vaccine. Subsequently another six and 11 infants responded to the second and third dose, respectively. The total cumulative response after the third dose was 23 of 36 vaccinees (63.9%). The geometric mean neutralizing antibody titers was lower in responders than in nonresponders before the first dose of vaccine indicating that maternal antibodies interfered with vaccine "take." Since the RIT 4237 strain is acid sensitive, gastric pH was measured at the time of each vaccination. Mean pH values in responders were not significantly different than those found in nonresponders. Therefore, vaccine failures cannot be due to inactivation of the rotavirus vaccine in the stomach but instead they can be attributed to high levels of maternal antibodies. At each vaccination, additional subjects seroconverted. Therefore, a multiple dose scheme is advisable to obtain an optimal immune response.