Rotavirus vaccines: A story of success

AbstractBy January 2015, rotavirus vaccination had been implemented in national vaccination programmes in 75 countries worldwide. Two live oral rotavirus vaccines are internationally available: human, monovalent vaccine and human–bovine pentavalent reassortant vaccine. Since January 2014, another live, oral human–bovine monovalent vaccine has been available in India. After implementation of rotavirus vaccines in childhood immunization programmes, there has been an over 90% reduction of rotavirus hospitalizations in industrialized and resource-deprived countries. Additionally, in Latin America, significant reduction of rotavirus-associated deaths has been recorded. Still, numerous countries do not recommend rotavirus mass vaccination because of assumed lack of cost-effectiveness and potential risk of intussusception, which is estimated at 1 per 50 000–70 000 doses of rotavirus vaccines. Cost-effectiveness of vaccination is affected in some countries by high price. Inclusion of herd protection and indirect costs in calculations for cost-effectiveness results in clear benefit: costs saved by health systems due to reduced rotavirus gastroenteritis hospitalizations far exceed the costs for implementation of rotavirus vaccination. There have been objections that high rotavirus vaccination coverage could put selective pressure on certain rotavirus strains against which protection after vaccination is less distinct. However, data now strongly suggest that even if there might be a relative increase of some specific genotypes after the use of rotavirus vaccines, this is not an absolute increase in incidence from certain genotypes and does not affect the overall effectiveness of rotavirus mass vaccination, which resulted in a major decrease of severe cases of rotavirus gastroenteritis in both industrialized and resource deprived countries

Genetic Variation of Bordetella pertussis in Austria

Contains fulltext : 155346.PDF (publisher's version ) (Open Access)In Austria, vaccination coverage against Bordetella pertussis infections during infancy is estimated at around 90%. Within the last years, however, the number of pertussis cases has increased steadily, not only in children but also in adolescents and adults, indicating both insufficient herd immunity and vaccine coverage. Waning immunity in the host and/or adaptation of the bacterium to the immunised hosts could contribute to the observed re-emergence of pertussis. In this study we therefore addressed the genetic variability in B. pertussis strains from several Austrian cities. Between the years 2002 and 2008, 110 samples were collected from Vienna (n = 32), Linz (n = 63) and Graz (n = 15) by nasopharyngeal swabs. DNA was extracted from the swabs, and bacterial sequence polymorphisms were examined by MLVA (multiple-locus variable number of tandem repeat analysis) (n = 77), by PCR amplification and conventional Sanger sequencing of the polymorphic regions of the prn (pertactin) gene (n = 110), and by amplification refractory mutation system quantitative PCR (ARMS-qPCR) (n = 110) to directly address polymorphisms in the genes encoding two pertussis toxin subunits (ptxA and ptxB), a fimbrial adhesin (fimD), tracheal colonisation factor (tcfA), and the virulence sensor protein (bvgS). Finally, the ptxP promoter region was screened by ARMS-qPCR for the presence of the ptxP3 allele, which has been associated with elevated production of pertussis toxin. The MLVA analysis revealed the highest level of polymorphisms with an absence of MLVA Type 29, which is found outside Austria. Only Prn subtypes Prn1/7, Prn2 and Prn3 were found with a predominance of the non-vaccine type Prn2. The analysis of the ptxA, ptxB, fimD, tcfA and bvgS polymorphisms showed a genotype mixed between the vaccine strain Tohama I and a clinical isolate from 2006 (L517). The major part of the samples (93%) displayed the ptxP3 allele. The consequences for the vaccination strategy are discussed