Vaccine company Valneva SE has shared positive results for its VLA1553 vaccine against chikungunya in adolescents. This progress, supported by Cepi – a foundation that seeks to accelerate the development of vaccines to counter emerging epidemics – and the European Union, aims to expand the use of the vaccine, already approved in the United States for adults.
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Valneva SE, a biotechnology company focused on vaccine development, recently announced promising results for its chikungunya virus vaccine VLA1553. These results come from phase 3 of their study, focused on adolescents, and add to initial safety data published in August 2023.
Extend the vaccine to the adolescent population
The project, funded by the Coalition for Epidemic Preparedness Innovations (CEPI for Coalition for Epidemic Preparedness Innovations, in English) and supported by the European Union’s Horizon 2020 program, is carried out in collaboration with the Butantan Institute, in Brazil. This study, named VLA1553-321, targets adolescents and aims to expand authorization for use of the vaccine to this age group.
This approach follows the recent approval of the vaccine for adults by the Food and Drug Administration (FDA) in the United States. This approval of the vaccine in the United States is based on phase 3 studies carried out on more than 4,000 adults. The results of these studies were published in 2022 and 2023, confirming the effectiveness and safety of the vaccine. These data along with the positive results on batch consistency and antibody persistence at twelve months were instrumental in obtaining regulatory approval.
In Europe, initial safety data was included in the dossier submitted to the European Medicines Agency (EMA) in October 2023.
Promising results
The study demonstrated that a single administration of VLA1553 induced a strong immune response in adolescents aged 12 to 18 years. These results confirm the effectiveness of the vaccine previously observed in adults.
The primary endpoint of the trial was met, with 98.8% of participants developing protective antibodies 28 days after vaccination. This performance far exceeds the FDA’s requirements, which stipulate a seroconversion rate greater than 70% to consider the study successful.
The vaccine showed high immunogenicity, with levels of neutralizing antibodies in adolescents comparable to those seen in adults who have already contracted the virus. Tolerability of VLA1553 was generally good in adolescents, whether previously infected with chikungunya or not, presenting a safety profile similar to that observed in adults.
The trial involved 754 adolescents, with data collected through 29e day post-vaccination. An independent safety data monitoring board regularly reviewed the data throughout the trial, without identifying any major safety concerns. The majority of adverse reactions observed were mild or moderate and resolved within a few days.
