Vaccine
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Should a highly pathogenic avian influenza virus, such as the H5N1 virus type currently circulating in birds, become transmissible among humans, an effective vaccine, rapidly available in vast quantities, would be the best tool to prevent high case-fatalities and the breakdown of health and social services. The number of vaccine doses that could be produced on demand has risen sharply over the last few years; however, it is still alarmingly short of the 13 billion doses that would be needed if two doses were required to protect fully the world's population. Most developing countries would be last in the queue to benefit from a pandemic vaccine. ⋯ To this end, the influenza vaccine technology transfer initiative was launched in 2007 and, to date, vaccine manufacturers in 11 developing countries have received grants to acquire the capacity to produce inactivated or live attenuated influenza vaccine for their populations. In addition, a centralized 'hub' has been established to facilitate training in the new technologies for scientists and regulators in the countries. This supplement of Vaccine is devoted to showcasing the interim results of the WHO initiative and the impressive progress made by the developing country manufacturers.
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To identify the rate of serious adverse events attributable to yellow fever vaccination with 17D and 17DD strains reported in active and passive surveillance data. ⋯ The databases in each country used different definitions, protocols, surveillance mechanisms for the initial identification and reporting of cases, and strategies for the clinical and laboratory follow up of cases. The pharmacovigilance databases provide three sets of estimates: a low estimate from the Brazilian and Australian data, a medium estimate from the US VAERS data, and a higher estimate from the UK and Swiss data. The estimates from the active surveillance data are lower (and strongly influenced by the Brazilian data) and the estimates from the passive surveillance studies are also lower (strongly influenced by the London Hospital for Tropical Diseases data from the early 1950s). Sophisticated pathology, histopathology and tests such as PCR amplicon sequencing are needed to prove that serious adverse events were actually caused by the yellow fever vaccine, and the availability of such diagnostic capability is strongly biased towards recent reports from developed countries. Despite these variations in the estimation of serious harm, overall the 17D and 17DD yellow fever vaccine has proven to be a very safe vaccine and is highly effective against an illness with high potential mortality rates.
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The 14,543 spontaneous reports of suspected adverse reactions received in EudraVigilance from 1 November 2009 to 30 April 2010 for three centrally authorized Influenza A/H1N1 vaccines marketed in the European Economic Area (Celvapan, Focetria and Pandemrix) were extracted to evaluate the effectiveness of recommendations to strengthen pharmacovigilance systems during the pandemic and illustrate methods of signal detection used by the European Medicines Agency in this context. The number of vaccinees on 30 April 2010 was estimated to be at least 37,166,000 with a reporting rate of 391 per million vaccinees. 81.4% of reports were received in a period of 2 months ending 31 December 2009. Reports for A/H1N1 vaccines had fewer missing values for date of birth, age, case narrative, vaccination date and reaction onset date than reports involving human papilloma virus vaccines in a pre-pandemic period but more missing batch numbers (46.6%), with earlier notification by health care professionals to national authorities (median of 7 days since reaction onset date) and by national authorities to EudraVigilance (4 days). ⋯ Observed-to-expected analyses were affected by uncertainties regarding the numbers of vaccinated individuals and age-specific background incidence rates. Imbalance analysis used by the Agency may overcome some of these limitations but needs further development. A multinational vaccine health outcome resource is needed to assess the burden of vaccine preventable diseases and the epidemiology of potential adverse outcomes, and to quickly evaluate safety signals, estimate the utilization, benefits and risks of vaccines and evaluate the effectiveness of public health measures.
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Vaccines with acceptable efficacy profile against the H1N1 A/California/7/2009 virus are needed for use in children. The two studies presented here evaluated the immunogenicity and the reactogenicity/safety of A/H1N1/2009 vaccines containing either 3.75 μg haemagglutinin antigen (HA) and AS03(A)-adjuvant (3.75 μg HA/AS03(A) study) (N=210 [53, 57 and 100 in the 3-5, 6-9 and 10-17 years age strata, respectively]) or 1.9 μg HA and AS03(B)-adjuvant (1.9 μg HA/AS03(B) study) (N=244 [61, 65 and 118 in the 3-5, 6-9 and 10-17 years age strata, respectively]), given as two-dose series. Although the haemagglutination inhibition antibody titres were higher in the 3.75 μg HA/AS03(A) study, both vaccine dosages were highly immunogenic and exceeded regulatory acceptance criteria after the first and the second doses. ⋯ Geometric mean titres increased from 456.5 to 1538.5 and from 297.9 to 1106.7 between the first and the second doses in the 3.75 μg HA/AS03(A) study and the 1.9 μg HA/AS03(B) study, respectively. Despite an observed slight increase of the reactogenicity following the second dose in the 3.75 μg HA/AS03(A) study, the vaccines safety profiles were considered clinically acceptable. In conclusion, both dosages of the AS03-adjuvanted A/H1N1/2009 pandemic influenza vaccines were highly immunogenic and well-tolerated in children and adolescents.
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Asymptomatic carriage of the opportunistic pathogen Streptococcus pneumoniae is known to precede the development of invasive disease. Young children are one of the major reservoirs for pneumococci and worldwide over 700,000 children under two years old die due to invasive pneumococcal disease each year. Heptavalent conjugate vaccine (PCV-7) was introduced into the UK childhood immunisation schedule in September 2006. Our objective was to assess the emergence of colonising serotypes in young children in the three years following PCV-7 implementation. ⋯ Although the overall pneumococcal carriage rate remained stable between 2006 and 2009, we observed a significant decrease in the serotype coverage of PCV-7 and PCV-13. PCV-7 was highly successful in reducing carriage of vaccine serotypes. However, the increase in the proportion of non-vaccine serotypes found both in our study and causing invasive disease currently in the UK, underlines the importance of continued surveillance of carriage and disease.