A new more affordable vaccine has been found effective against five of the six meningococcal bacteria strains that cause menengitis in Africa.
The new pentavalent vaccine against meningococcal disease, codenamed NmCV-5,has been found safe in trials, inducing a strong immune response across five strains of meningococcal bacteria: A, C, W, Y and X. There is currently no licensed vaccine for the X strain.
The latest trial was designed to provide the World Health Organisation (WHO) with the evidence needed to license the new vaccine for future epidemic control.
The results, published in the New England Journal of Medicine, on May 25 show that the immune responses generated by a single dose of NmCV-5 after 28 days were generally higher than those generated by currently used MenACWY-D. It also induced a strong immune response to the meningococcal X strain in 97 percent of participants.
Experts are upbeat that the successful trial of the NmCV-5 pentavalent vaccine could provide a “critical tool” for defeating epidemic meningitis across Africa by 2030.
If untreated, Meningococcal meningitis is associated with high fatality of up to 50 percent of infected patients.
The WHO estimates there were more than 2.5 million cases of meningitis worldwide, and that the disease caused nearly 250,000 deaths in 2019.
Developing affordable vaccines that provide broad coverage against meningococcal disease strains is a key part of the WHO Defeating Meningitis by 2030 Global Roadmap.
Subtypes
Meningococcal disease is caused by 12 different subtypes of meningococcal bacteria, with types A, B, C, W, X and Y causing most disease.
Existing vaccines protect against some of these groups: for instance, the Men A and Men C vaccines protect against A or C, while the MenACWY and MCV4 vaccines protect against serogroups A, C, W, and Y.
The Phase III trial compared the immune response generated by the new pentavalent vaccine NmCV-5 against that of the licensed quadrivalent MenACWY-D vaccine in 1,800 healthy 2-29-year-olds in Mali and The Gambia.
“After 28 days, across all ages, the immune responses generated by a single dose of NmCV-5 were generally higher than those generated by MenACWY-D,” said the research team.
In addition, NmCV-5 induced a strong immune response to the emerging meningococcal X strain for which there is currently no licensed vaccine.
The study team also found no safety concerns with NmCV-5.
Issues with supply and affordability have limited use of quadrivalent meningococcal vaccines across the ‘meningitis belt’, a swathe of sub-Saharan Africa at high-risk of epidemics of meningococcal and pneumococcal meningitis. In addition, meningococcal X has emerged with potential to cause epidemics across the ‘meningitis belt’, and a vaccine to prevent against this strain is urgently needed.
Building on the success of the Meningitis Vaccine Project, which developed MenAfriVac, a meningococcal A vaccine, the Serum Institute of India and PATH developed NmCV-5 with the goal of eliminating meningococcal disease in sub-Saharan Africa.
More cost-effective production methods should mean that NmCV-5 can be made available at lower cost than existing quadrivalent vaccines, overcoming a major stumbling block to it being widely available across the ‘meningitis belt’. The trial was designed to provide WHO with the evidence needed to license the new vaccine for future epidemic control.
“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 to interrupting and preventing devastating epidemics of meningitis in the meningitis belt. We hope it will ensure the goal of defeating epidemic meningitis by 2030, set out in the Global Roadmap, becomes a reality,” said Dr Ed Clarke, a paediatrician from the Vaccines and Immunity Theme at MRC Unit The Gambia at LSHTM and co-researcher.
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