Positive effect of meningococcal C vaccination on serogroup replacement in Neisseria meningitidis

Clonal Distribution of Invasive Neisseria meningitidis Serogroup C Strains Circulating from 1976 to 2005 in Greater São Paulo, Brazil

“…Capsular switching may occur naturally, and immunization with vaccines that target serogroup capsules could potentially favor the emergence of serogroup B ST-11 complex strains as reported in Canada and Spain, where serogroup B ST-11 complex strains have emerged since the introduction of serogroup C conjugate vaccines (1,24,33). In GSP, only two serogroup B 2a:P1.5,2 ET-5 complex strains were found, 16 and 20 years after the AC vaccination campaign, when similar prevalence of MD caused by serogroups B and C was reported (26).…”

Detección de cepas de Neisseria meningitidis resistentes a rifampicina en el Uruguay

“…Se utilizaron dos cepas de referencia como control: la cepa del serogrupo B, H44/76, que ha sido totalmente secuenciada (9) y la cepa 1103 del serogrupo C, que había sido caracterizada como representativa de un clon que se diseminó en el Uruguay en la década de 1990 (10).…”

“…Los REFERENCIAS casos por B:2a:P1.5 notificados presentaron una tasa de letalidad y una frecuencia de casos secundarios mayor que la de los casos ocasionados por otros meningococos B, aunque estas diferencias no son estadísticamente significativas (12). En el Uruguay, se realizó en 1996 una campaña de vacunación con vacuna A-C polisacárida en respuesta a un brusco incremento en el número de casos de meningitis bacterianas ocasionado por la diseminación de dos clones de N. meningitidis del serogrupo C en la década de 1990 (10). Entre 2001 y 2002, se realizó otra campaña de vacunación con vacuna B-C, también en respuesta a un brote en la ciudad de Santa Lucía, cercana a Montevideo.…”

B:2a:P1.5 Meningococcal Strains Likely Arisen from Capsular Switching Event Still Spreading in Spain

“…In response, a mass immunization campaign focusing on members of the population that were between 18 months and 19 years old was implemented, first with the polysaccharide AϩC vaccine in most of the country during 1997 and then with the new C conjugate polysaccharide vaccines introduced into the Spanish routine vaccination schedule in 2000 (4). The efficacy of both interventions was quite high (6,15), but immune pressure might have the potential to select those organisms that have their capsules replaced (4,8,10). Although the frequency of the capsular switching event is not known in nature, in a population immunized against meningococci from serogroup C, replacement of serogroup C 2a:P1.5 ST11 by serogroup B 2a:P1.5 ST11 meningococci might easily occur.…”

“…Although the frequency of the capsular switching event is not known in nature, in a population immunized against meningococci from serogroup C, replacement of serogroup C 2a:P1.5 ST11 by serogroup B 2a:P1.5 ST11 meningococci might easily occur. In fact, since 2000 there have been two clusters associated with B:2a:P1.5 ST11 strains in northern Spain (7,10,12).…”