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Mixed RotaTeq, Rotarix vaccine schedules safe, effective in children
Vaccine schedules for infants who used two different rotavirus vaccines were safe and produced immune responses comparable to single-vaccine schedules, according to recent research in Pediatrics.
“Our study is the first to our knowledge to demonstrate that the two formulations of rotavirus vaccine may be administered interchangeably to infants when a shortage of one formulation occurs,” Andi L. Shane, MD, MPH, MSc, assistant professor in the department of pediatrics at Emory University School of Medicine, told Infectious Diseases in Children. “This is extremely important as there is an upper age limit to receive the first and last doses of rotavirus vaccines. If a rotavirus vaccine series is started by one formulation, comparable immunogenicity is expected if the series is completed with another formulation.”
Andi L. Shane
The researchers studied a cohort of 1,393 children aged 6 to 14 weeks, at multiple centers between 2011 and 2013. The two FDA-approved, commercially licensed rotavirus vaccines — RotaTeq (RV5, Merck) and Rotarix (RV1, GlaxoSmithKline) — were used in the study. Participants were randomly assigned to one of five study groups:
- a three-dose RV5 group;
- a two-dose RV1 group;
- a single dose of RV5 with two additional doses of RV1 group;
- two doses of RV5 with an additional single dose of RV1 group; and
- a single dose of RV1 with two additional doses of RV5 group.
The researchers conducted immunogenicity testing 1 month after the final dose was administered to each participant. Safety assessment was conducted throughout the study, and serious adverse events were recorded.
Study results showed that all mixed-vaccine groups produced immune responses that were noninferior when compared with the single-vaccine groups. The percentage of children responsive to at least one vaccine antigen ranged from 77% to 96%, across the entire study cohort. The two-dose RV1 group contained the lowest proportion of children with immune responses across all antigens tested, while the group administered RV1 then two doses of RV5 had the highest percentage of immune responses.
Shane and colleagues wrote that the mixed-vaccine groups produced a safety profile comparable to the single-dose groups. Only one hospitalization during the study period — an infant with gastroenteritis — was determined to be related to rotavirus vaccine. The researchers noted that this case resolved without any sequelae.
Kathryn M. Edwards
“Our study has clearly shown that there is not an inhibition in immunogenicity with the sequential schedule and supports that vaccines may be given interchangeably,” Kathryn M. Edwards, MD, professor of pediatrics at Vanderbilt University and an Infectious Diseases in Children Editorial Board member, Shane and colleagues wrote. “We have shown that, should the recommended rotavirus vaccine schedules administration not be possible, sequential mixed rotavirus formulation represents a safe and an immunogenic choice.”
According to Shane, these findings will ultimately ensure that more children are protected against the threat of rotavirus infection.
“Our findings increase the likelihood of completion of a rotavirus vaccine series within the licensing window in the setting of a shortage or unavailability of one of the rotavirus vaccine products,” Shane said in an interview.
Reassuring findings for general practitioners
In a related editorial, Carrie L. Byington, MD, of the department of pediatrics at the University of Utah and chair of the AAP’s Committee on Infectious Diseases, and Yvonne Maldonado, MD, of the department of pediatrics at Stanford University, wrote that Shane and colleagues’ study provides reassuring guidance for pediatricians administering vaccines in “real-world” scenarios.
“Despite the rigorous testing required for licensure, questions about vaccine administration in clinical settings may persist, particularly when there are multiple products licensed to prevent the same infection,” Byington and Maldonado wrote. “Expert opinion has led the [AAP’s Committee on Infectious Diseases] to advise providers that timely completion of immunization with any available licensed product is better than delaying immunization for a specific product.
Carrie L. Byington
Yvonne Maldonado
“[This study] supports this principle and reassures us that for rotavirus vaccines, immunization with a mixed series of vaccines is safe and results in an immune response that is noninferior to that generated by immunization with any single product.”
According to Byington and Maldonado, this study also highlights the need for government-funded vaccine research in areas where pharmaceutical companies have competing interests with researchers.
“Without these federally funded resources, it is unlikely that the evaluation of multiple rotavirus vaccine combinations would have been conducted,” they wrote. “Individual vaccine manufacturers have little or no incentive to test their licensed products in combination with those of other manufacturers. We must remember that our advocacy should also include working to ensure that the research infrastructure of the nation is strong and that adequate resources are devoted to investigations that will benefit the health of children.” – by David Costill
Disclosure: Edward reports serving as a data and safety monitoring board member for Novartis and receiving research funding from Novartis for unrelated vaccine studies. Please see the full study for a list of all other authors’ relevant financial disclosures.
