A trial investigating a new vaccine targeting meningococcal disease, a leading cause of meningitis and blood poisoning, has concluded that the vaccine is safe and generates a robust immune response against five strains of meningococcal bacteria: A, C, W, Y, and X.
In the phase 3 trial, the immune response elicited by the new pentavalent vaccine NmCV-5 was compared to that of the licensed quadrivalent MenACWY-D vaccine among 1,800 healthy individuals aged 2-29 in Mali and The Gambia. After 28 days, the immune responses following a single dose of NmCV-5 were generally higher than those observed with MenACWY-D, across all age groups.
The trial also demonstrated that NmCV-5 provoked a strong immune response against the emerging meningococcal X strain, for which there is currently no licensed vaccine available. Importantly, no safety concerns were identified with NmCV-5.
Published in the New England Journal of Medicine, the study was led by a team of researchers from the Medical Research Council (MRC) Unit The Gambia at the London School of Hygiene & Tropical Medicine (LSHTM), in collaboration with researchers from Bamako in Mali.
Meningitis is estimated to have caused 250,000 deaths in 2019, and the World Health Organization (WHO) emphasizes the development of affordable vaccines that provide broad coverage against meningococcal disease strains as a crucial aspect of its Defeating Meningitis by 2030 Global Roadmap.
Supply and affordability challenges have restricted the use of quadrivalent meningococcal vaccines in the “meningitis belt,” a region in sub-Saharan Africa highly susceptible to meningococcal and pneumococcal meningitis epidemics. Furthermore, the emergence of the meningococcal X strain presents a pressing need for a vaccine to combat this particular strain.
Leveraging the success of the Meningitis Vaccine Project, which introduced MenAfriVac, a meningococcal A vaccine, the Serum Institute of India and PATH developed NmCV-5 with the aim of eradicating meningococcal disease in sub-Saharan Africa.
By employing more cost-effective production methods, it is anticipated that NmCV-5 can be made available at a lower cost than existing quadrivalent vaccines, thereby overcoming a significant hurdle to widespread adoption across the “meningitis belt.” The trial was designed to furnish the WHO with the requisite evidence for licensing the new vaccine for future epidemic control.
Dr. Ed Clarke, a paediatrician from the Vaccines and Immunity Theme at MRC Unit The Gambia at LSHTM and co-author of the study, expressed enthusiasm regarding the results, stating, “We expect NmCV-5 to provide children and young adults with reliable protection against meningitis caused by the meningococcal bacteria. The new vaccine will be a critical tool in interrupting and preventing devastating meningitis epidemics in the meningitis belt. We hope it will contribute to the realization of the goal of defeating epidemic meningitis by 2030, as outlined in the Global Roadmap.”
Dr. Ama Umesi, co-author from MRC Unit The Gambia at LSHTM, stressed the urgency of epidemic preparedness and the importance of accessible and affordable vaccines to counteract meningitis outbreaks, particularly in the meningitis belt region. She noted the potential transformative impact of meningitis vaccines in preventing catastrophic outcomes during outbreaks and expressed optimism regarding the availability of relevant vaccines for common strains within the region, thanks to collaborative multicenter trials.
The trial, conducted in June 2021, administered vaccinations to 1,800 participants who were divided into three age groups: 2-10 years, 11-17 years, and 18-29 years. All participants were of African descent, with females accounting for 50.7% of the cohort.