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Background Two-dose varicella vaccination is recommended for optimal control of varicella in populations with high (>90%) 1-dose coverage. Optimal timing of the second dose may depend on whether breakthrough varicella results from primary vaccine failure (no protective immunity after vaccination) or secondary vaccine failure (waning protective immunity). Methods Published literature (1995 to 2012) on vaccine failure after varicella vaccination cited in PubMed and other online sources was reviewed. Results Nineteen publications detailed 21 varicella outbreaks with breakthrough varicella rates ranging from 0% to 42%; the publications showed no consistent trend between breakthrough varicella rate and time since vaccination. Conclusions Literature to date indicates a relatively high rate of primary vaccine failure and limited evidence of secondary vaccine failure among 1-dose varicella vaccine recipients, suggesting that a short interval between 2 doses might be preferable in countries considering implementation of universal varicella vaccination to reduce breakthrough varicella. However, any potential disruption to well-established vaccination schedules should be considered.

Pneumococcal infection is a major cause of morbidity and mortality worldwide. The burden of disease associated with S. pneumoniae is largely preventable through routine vaccination. Pneumococcal conjugate vaccines (e.g. PCV7, PCV13) provide protection from invasive pneumococcal disease as well as non-invasive infection (pneumonia, acute otitis media), and decrease vaccine-type nasopharyngeal colonisation, thus reducing transmission to unvaccinated individuals. PCVs have also been shown to reduce the incidence of antibiotic-resistant pneumococcal disease. Surveillance for pneumococcal disease is important to understand local epidemiology, serotype distribution and antibiotic resistance rates. Surveillance systems also help to inform policy development, including vaccine recommendations, and monitor the impact of pneumococcal vaccination. National pneumococcal surveillance systems exist in a number of countries in Central and Eastern Europe (such as Croatia, Czech Republic, Hungary, Poland, Romania and Slovakia), and some have introduced PCVs (Czech Republic, Hungary, Kazakhstan, Russia, Slovakia and Turkey). Those countries without established programs (such as Kazakhstan, Russia and Ukraine) may be able to learn from the experiences of those with national surveillance systems. The serotype distributions and impact of PCV13 on pediatric pneumococcal diseases are relatively similar in different parts of the world, suggesting that approaches to vaccination used elsewhere are also likely to be effective in Central and Eastern Europe. This article briefly reviews the epidemiology of pneumococcal disease, presents the latest surveillance data from Central and Eastern Europe, and discusses any similarities and differences in these data as well the potential implications for vaccination policies in the region.

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BackgroundGSK’s varicella vaccine contains human serum albumin (HSA) which is used to stabilize the virus and prevent immunogens from adhering to the injection vial walls. However, because HSA is derived from human blood, there is a theoretical risk that it might contain infectious agents which could be unsafe for humans. Given this concern, a study was undertaken to compare the immunogenicity and safety of a new formulation without HSA with the currently licensed varicella vaccine in the Czech Republic and Hungary.MethodsHealthy children aged 11–21 months received two doses of the varicella vaccine either with or without HSA. Antibody titres against varicella-zoster virus (anti-VZV) were measured 42 days after each dose, using an immunofluorescence assay (IFA, cut-off = 4dilution−1) and enzyme linked immunosorbent assay (ELISA, cut-off = 25 mIU/ml). Solicited local symptoms were recorded during a 4-day post-vaccination follow-up period; solicited general and unsolicited symptoms were recorded during a 43-day post-vaccination follow-up period and serious adverse event (SAEs) were recorded throughout the study.ResultsOf 244 children (mean age = 15.2 months [SD = 3.2]) vaccinated in the study, 233 (vaccine without HSA N = 117; vaccine containing HSA N = 116) formed the according-to-protocol immunogenicity cohort. Observed seroconversion/seroresponse rates were >98 and 100 %, 42 days after doses 1 and 2, respectively. The rates were within the same range in both groups, irrespective of the testing assay. The varicella vaccine without HSA was non-inferior to the licensed vaccine in terms of anti-VZV antibody Geometric Mean Titre/Concentration ratio (1.12 [95 % CI:0.86–1.46] by IFA; 1.12 [95 % CI:0.93–1.33] by ELISA) approximately six weeks after the first dose of the 2-dose vaccination course. The incidence of solicited and unsolicited symptoms was similar after both vaccines; low-grade fever was numerically higher after the first dose of the varicella vaccine without HSA. Seven SAEs were reported, none of which were fatal or considered to be vaccine-related.ConclusionsThe first dose of a new varicella vaccine without HSA was immunologically non-inferior to the licensed varicella vaccine. After two doses, both vaccines had acceptable safety profiles in children aged 11–21 months in the Czech Republic and Hungary.Trial registrationNCT00568334, registered on 5 December 2007 (www.clinicaltrials.gov).