Immunogenicity of Fractional Doses of Tetravalent A/C/Y/W135 Meningococcal Polysaccharide Vaccine: Results from a Randomized Non-Inferiority Controlled Trial in Uganda
![Thumbnail](/xmlui/bitstream/handle/123456789/1005/Immunogenicity%20of%20Fractional%20Doses%20of%20Tetravalent%20A_C_Y_W135%20Meningococcal%20Polysaccharide%20Vaccine.pdf.jpg?sequence=4&isAllowed=y)
View/ Open
Date
2008Author
Guerin, Philippe J.
Næss, Lisbeth M.
Fogg, Carole
Rosenqvist, Einar
Pinoges, Loretxu
Bajunirwe, Francis
Nabasumba, Carolyn
Borrow, Ray
Frøholm, Leif O.
Ghabri, Salah
Batwala, Vincent
Twesigye, Rogers
Aaberge, Ingeborg S.
Røttingen, John-Arne
Piola, Patrice
Caugant, Dominique A.
Metadata
Show full item recordAbstract
Background: Neisseria meningitidis serogroup A is the main causative pathogen of meningitis epidemics in sub-Saharan Africa. In recent years, serogroup W135 has also been the cause of epidemics. Mass vaccination campaigns with polysaccharide vaccines are key elements in controlling these epidemics. Facing global vaccine shortage, we explored the use of fractional doses of a licensed A/C/Y/W135 polysaccharide meningococcal vaccine.
Methods and Findings: We conducted a randomized, non-inferiority trial in 750 healthy volunteers 2–19 years old in Mbarara, Uganda, to compare the immune response of the full dose of the vaccine versus fractional doses (1/5 or 1/10). Safety and tolerability data were collected for all subjects during the 4 weeks following the injection. Pre- and post-vaccination sera were analyzed by measuring serum bactericidal activity (SBA) with baby rabbit complement. A responder was defined as a subject with a $4-fold increase in SBA against a target strain from each serogroup and SBA titer $128. For serogroup W135, 94% and 97% of the vaccinees in the 1/5- and 1/10-dose arms, respectively, were responders, versus 94% in the full-dose arm; for serogroup A, 92% and 88% were responders, respectively, versus 95%. Non-inferiority was demonstrated between the full dose and both fractional doses in SBA seroresponse against serogroups W135 and Y, in total
population analysis. Non-inferiority was shown between the full and 1/5 doses for serogroup A in the population nonimmune prior to vaccination. Non-inferiority was not shown for any of the fractionate doses for serogroup C. Safety and tolerability data were favourable, as observed in other studies.
Conclusions: While the advent of conjugate A vaccine is anticipated to largely contribute to control serogroup An outbreaks in Africa, the scale-up of its production will not cover the entire ‘‘Meningitis Belt’’ target population for at least the next 3 to 5 years. In view of the current shortage of meningococcal vaccines for Africa, the use of 1/5 fractional doses should be considered as an alternative in mass vaccination campaigns.
Collections
- Research Articles [432]