Browsing by Author "Rosenqvist, Einar"

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    Immunogenicity of Fractional Doses of Tetravalent A/C/Y/W135 Meningococcal Polysaccharide Vaccine: Results from a Randomized Non-Inferiority Controlled Trial in Uganda
    (PLoS neglected tropical diseases, 2008) 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.; Røttinge, John-Arne; Piola, Patrice; Caugan, Dominique A.
    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. 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 non-immune prior to vaccination. Non-inferiority was not shown for any of the fractionate doses for serogroup C. Safety and tolerability data were favorable, as observed in other studies. While the advent of conjugate A vaccine is anticipated to largely contribute to control serogroup A 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.
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    Pharyngeal carriage of Neisseria meningitidis in 2–19-year-old individuals in Uganda
    (Transactions of The Royal Society of Tropical Medicine and Hygiene, 2006) Caugant, Dominique A.; Fogg, Carole; Bajunirwe, Francis; Piola, Patrice; Twesigye, Rogers; Mutebi, Fred; Frøholm, L. Oddvar; Rosenqvist, Einar; Batwala, Vincent; Aaberge, Ingeborg S.; Rottingen, John-Arne; Guerin, Philippe J.
    In southern Uganda, only sporadic cases of serogroup A meningococcal disease have been reported since 2000. As part of an immunogenicity study of the tetravalent meningococcal polysaccharide vaccine, nasopharyngeal swab samples were collected twice, 4 weeks apart, from 2–19-year-old healthy individuals in Mbarara, Uganda. Only 15 (2.0%) of the 750 individuals carried meningococci asymptomatically. Most of the strains were non-serogroupable and none were serogroup A. However, two individuals carried a serogroup W135 strain, sequence type (ST)-11, similar to the clone that was responsible for the epidemic in Burkina Faso in 2002. Our study further demonstrates the geographical spread of serogroup W135 ST-11 strain and thus the potential epidemic risk.
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    Pharyngeal carriage of Neisseria meningitidis in 2—19-year-old individuals in Uganda
    (Transactions of the Royal Society of Tropical Medicine and Hygiene, 2006) Caugant, Dominique A.; Fogg, Carole; Bajunirwe, Francis; Piola, Patrice; Guerin, Philippe J.; Twesigye, Rogers; Mutebi, Fred; Frøholm, L. Oddvar; Rosenqvist, Einar; Batwala, Vincent; Aaberge, Ingeborg S.; Rottingen, John-Arne
    In southern Uganda, only sporadic cases of serogroup A meningococcal disease have been reported since 2000. As part of an immunogenicity study of the tetravalent meningococcal polysaccharide vaccine, nasopharyngeal swab samples were collected twice, 4 weeks apart, from 2—19-year-old healthy individuals in Mbarara, Uganda. Only 15 (2.0%) of the 750 individuals carried meningococci asymptomatically. Most of the strains were non-serogroupable and none were serogroup A. However, two individuals carried a serogroup W135 strain, sequence type (ST)-11, similar to the clone that was responsible for the epidemic in Burkina Faso in 2002. Our study further demonstrates the geographical spread of serogroup W135 ST-11 strain and thus the potential epidemic risk.