Pediatric cell-based vaccine as good as egg-based vaccine for influenza, clinical trial

A pediatric quadrivalent inactivated cell-based flu vaccine (QIVc) is proving to be just as good in terms of immunogenicity and safety as an egg-based vaccine (QIV)—and is a step forward in pediatric vaccines. Young children have an elevated risk for complications from influenza, as this flu season in Canada is showing. While vaccination is the most effective intervention for preventing disease and associated complications, it could be even more effective if the match of the vaccine to circulating strains were better. But a problem has been that with egg-based vaccine production the match of the vaccine to circulating strains of virus may end up not being as good because strains of flu virus, especially H3N2, may mutate during production. This can lead to a product that is a poorer match and less effective. Read: Nose swab may help predict which children will have worse outcomes from RSV However, “cell-based influenza vaccine manufacturing avoids adaptive mutations of egg-based production, providing a truer match to the World Health Organization-selected strains for each influenza season,” said researchers in a study in Pediatrics. There, they provided details of a phase-3 randomized trial comparing a new cell-based vaccine to a standard one. “This is the first phase 3 safety and immunogenicity study to evaluate cell culture–derived influenza vaccine starting at 6 months of age, the youngest population for whom seasonal influenza vaccine is recommended,” the study stated. The study was conducted during the Northern Hemisphere 2019–2020 influenza season at 47 centres across the U.S. The goal was to evaluate safety and immunogenicity as compared with a U.S.-licensed QIV, and to show non-inferiority of the QIVc. Immunogenicity was determined via blood tests. Eligible subjects were randomly assigned to receive either QIVc or QIV and divided into two groups stratified by months of age: six to 23 months, and 24 to 47 months. Participants received two doses of the study vaccine if at least two doses of influenza vaccine had not been previously received either in the same or different influenza seasons, or if influenza vaccination history was unknown. Those who had influenza vaccination within six months before study entry were excluded. Blood samples were collected from each child before they underwent vaccination on day one, and again 28 days after the last vaccination in the study. A safety follow-up period was concluded 180 days after the final vaccination. The QIVc study vaccine used was Flucelvax Quadrivalent and the QIV was Afluria Quadrivalent. Doses and injection sites were adjusted according to age. The strains of flu covered by the vaccines were A/H1N1, A/H3N2; B/Yamagata, and B/Victoria. Final analyses were based on a total of 1,667 subjects with 1,092 randomized to receive the QIVc and 575 the QIV. Half the subjects were female, 37% overall were aged 6 to 23 months and 63% were aged 24 to 47 months. Overall, 66% of the cohort was Caucasian and about 28% were Black. Assays based on the blood samples revealed similar immune responses to the vaccines, and that the QIVc was indeed non-inferior to the standard vaccine. Adverse events (AEs) were similar for both groups too, with most being mild to moderate in severity. The most common local AEs were tenderness and erythema at the injection site, and the most common systemic AEs were irritability and sleepiness. Both vaccine groups had similar rates of fever, with fever of 38C or more reported for 6.8% and 6.9% of subjects in the QIVc and QIV groups, respectively. Temperatures of 40C or more reported in fewer than 1% of subjects in either group. “The primary immunogenicity endpoints of noninferiority of QIVc compared with a U.S.-licensed QIV were achieved for all 4 vaccine strains,” the study said. A commentary in the same issue of Pediatrics stated “By demonstrating the safety and immunogenicity of cell-based vaccines in young children, (the study) represents an important advancement for pediatric influenza vaccines.” It was written by Drs. Jennifer Nayoak and Mary Caserta, both from the University of Rochester, New York. They noted that “influenza virus is unique in that ongoing viral evolution presents challenges for the rational development of broadly protective influenza vaccines.” And that cell-based platforms are less conducive to mutations occurring. “QIVc will provide an additional influenza vaccine platform for the pediatric population and, importantly, a nonegg-based vaccine that might result in improved antigenic match in some influenza seasons. This could have important implications with regard to imprinting, or the establishment of lasting anti-influenza protective immunity in childhood,” they said. The FluWatch Report for October 30 to November 5, 2022, from the Public Health Agency of Canada (PHAC) shows that influenza outbreaks are occurring across the country. For pediatrics, the number of “weekly influenza-associated hospitalizations are well above levels typical of this time of year.”

Pediatric cell-based vaccine as good as egg-based vaccine for influenza, clinical trial

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