Diphtheria in the postepidemic period, Europe, 2000-2009.

Diphtheria incidence has decreased in Europe since its resurgence in the 1990s, but circulation continues in some countries in eastern Europe, and sporadic cases have been reported elsewhere. Surveillance data from Diphtheria Surveillance Network countries and the World Health Organization European Region for 2000-2009 were analyzed. Latvia reported the highest annual incidence in Europe each year, but the Russian Federation and Ukraine accounted for 83% of all cases. Over the past 10 years, diphtheria incidence has decreased by >95% across the region. Although most deaths occurred in disease-endemic countries, case-fatality rates were highest in countries to which diphtheria is not endemic, where unfamiliarity can lead to delays in diagnosis and treatment. In western Europe, toxigenic Corynebacterium ulcerans has increasingly been identified as the etiologic agent. Reduction in diphtheria incidence over the past 10 years is encouraging, but maintaining high vaccination coverage is essential to prevent indigenous C. ulcerans and reemergence of C. diphtheriae.

Effectiveness of the typhoid Vi vaccine in overseas travelers from England.

BACKGROUND: Approximately 500 cases of enteric fever, caused by Salmonella enterica serovar Typhi and Paratyphi, are reported in the UK each year. The majority are associated with travel to the Indian subcontinent. The typhoid Vi vaccine protects against S. Typhi and is available to travelers from their general practice or private clinics. The effectiveness of this vaccine has been assessed previously in endemic regions of the world but not in travelers. METHODS: Data from the enhanced surveillance scheme concerning persons in England aged ≥2 years who traveled from the UK and contracted culture-confirmed enteric fever were used to calculate the effectiveness of the vaccine in travelers. A "case-case" case-control design was used, in which patients with typhoid comprised the "cases" and those with paratyphoid acted as "controls." RESULTS: The overall effectiveness of the vaccine, adjusted for age group, sex, ethnicity, birth in a typhoid-endemic country, and year (of receipt of specimen), was 65% (95% confidence interval 53%-73%). Effectiveness did not vary across subgroups of any of the factors in the model, but there was some evidence of waning effectiveness of the vaccine with increasing time since receipt (trend p = 0.05). CONCLUSIONS: The vaccine has been demonstrated to have a similar effectiveness in travelers as that found in endemic populations. It appears to be protective in all ages, including in young children (aged 2-5 years), a finding not consistently replicated in other studies. However, good hygiene practices are necessary in addition to vaccination to prevent infection. The "case-case" case-control design provides a valuable method of calculating the effectiveness of this vaccine in travelers, given the availability of paratyphoid controls, a population with similar demographics and risk exposures.

Childhood vaccination coverage by ethnicity within London between 2006/2007 and 2010/2011.

OBJECTIVES: To assess childhood vaccination coverage at first, second and fifth birthdays by ethnicity in London between 2006/2007 and 2010/2011 and identify factors relating to lower coverage. DESIGN: Data concerning receipt of diphtheria-containing vaccines were extracted from child health information systems (CHISs) and sent to the Health Protection Agency. SETTING: Nine London Primary Care Trusts (PCTs). PARTICIPANTS: Records for 315 381 children born April 2001-March 2010. MAIN OUTCOME MEASURES: Receipt of a full primary course of diphtheria-containing vaccines at first and second birthdays, and a primary course and preschool booster at fifth birthday. RESULTS: Consistently good vaccine coverage of the primary course (>88% at first birthday, >89% at second birthday) was achieved across the five largest ethnic groups. Coverage of the preschool booster at fifth birthday was >65% across the five largest ethnic groups. Lowest coverage was observed in smaller ethnic groups. Deprivation was not a strong indicator of coverage overall, and for most ethnic groups there was no relationship between deprivation and coverage. Coverage was significantly lower in children not assigned to a general practitioner practice in the CHIS. CONCLUSIONS: Smaller, less well-established ethnic groups within a PCT may require specific targeting to ensure children are fully immunised and to improve record keeping. Unregistered children need particular attention and may be missed by current scheduling processes in London. In order to monitor the impact of the current National Health Service (NHS) reorganisation on inequalities in access to healthcare data on country of birth, in addition to ethnicity, should be available for analysis.

Immunity to tetanus and diphtheria in the UK in 2009.

INTRODUCTION: This study aimed to estimate the immunity of the UK population to tetanus and diphtheria, including the potential impact of new glycoconjugatate vaccines, and the addition of diphtheria to the school leaver booster in 1994. METHODS: Residual sera (n=2697) collected in England in 2009/10 were selected from 18 age groups and tested for tetanus and diphtheria antibody. Results were standardised by testing a panel of sera (n=150) to enable comparison with a previously (1996) published serosurvey. Data were then standardised to the UK population. RESULTS: In 2009, 83% of the UK population were protected (≥0.1 IU/mL) against tetanus compared to 76% in 1996 (p=0.079), and 75% had at least basic protection against diphtheria (≥0.01 IU/mL) in 2009 compared to 60% in 1996 (p<0.001). Higher antibody levels were observed in those aged 1-3 years in 2009 compared to 1996 for both tetanus and diphtheria. Higher diphtheria immunity was observed in those aged 16-34 years in 2009 compared to 1996 (geometric mean concentration [GMC] 0.15 IU/mL vs. 0.03 IU/mL, p<0.001). Age groups with the largest proportion of susceptible individuals to both tetanus and diphtheria in 2009 were <1 year old (>29% susceptible), 45-69 years (>20% susceptible) and 70+ years (>32% susceptible). Low immunity was observed in those aged 10-11 years (>19% susceptible), between the scheduled preschool and school leaver booster administration. DISCUSSION: The current schedule appears to induce protective levels; increases in the proportions protected/GMCs were observed for the ages receiving vaccinations according to UK policy. Glycoconjugate vaccines appear to have increased immunity, in particular for diphtheria, in preschool age groups. Diphtheria immunity in teenagers and young adults has increased as a result of the addition of diphtheria to the school leaver booster. However, currently older adults remain susceptible, without any further opportunities for immunisations planned according to the present schedule.

Identifying regional variation in the prevalence of postpartum haemorrhage: a systematic review and meta-analysis.

OBJECTIVE: To provide regional estimates of the prevalence of maternal haemorrhage and explore the effect of methodological differences between studies on any observed regional variation. METHODS: We conducted a systematic review of the prevalence of maternal haemorrhage, defined as blood loss greater than or equal to 1) 500 ml or 2) 1000 ml in the antepartum, intrapartum or postpartum period. We obtained regional estimates of the prevalence of maternal and severe maternal haemorrhage by conducting meta-analyses and used meta-regression to explore potential sources of between-study heterogeneity. FINDINGS: No studies reported the prevalence of antepartum haemorrhage (APH) according to our definitions. The prevalence of postpartum haemorrhage (PPH) (blood loss ≥500 ml) ranged from 7.2% in Oceania to 25.7% in Africa. The prevalence of severe PPH (blood loss ≥1000 ml) was highest in Africa at 5.1% and lowest in Asia at 1.9%. There was strong evidence of between-study heterogeneity in the prevalence of PPH and severe PPH in most regions. Meta-regression analyses suggested that region and method of measurement of blood loss influenced prevalence estimates for both PPH and severe PPH. The regional patterns changed after adjusting for the other predictors of PPH indicating that, compared with European women, Asian women have a lower prevalence of PPH. CONCLUSIONS: We found evidence that Asian women have a very low prevalence of PPH compared with women in Europe. However, more reliable estimates will only be obtained with the standardisation of the measurement of PPH so that the data from different regions are comparable.

Density-dependent mortality of the human host in onchocerciasis: relationships between microfilarial load and excess mortality.

BACKGROUND: The parasite Onchocerca volvulus has, until recently, been regarded as the cause of a chronic yet non-fatal condition. Recent analyses, however, have indicated that in addition to blindness, the parasite can also be directly associated with human mortality. Such analyses also suggested that the relationship between microfilarial load and excess mortality might be non-linear. Determining the functional form of such relationship would contribute to quantify the population impact of mass microfilaricidal treatment. METHODOLOGY/PRINCIPAL FINDINGS: Data from the Onchocerciasis Control Programme in West Africa (OCP) collected from 1974 through 2001 were used to determine functional relationships between microfilarial load and excess mortality of the human host. The goodness-of-fit of three candidate functional forms (a (log-) linear model and two saturating functions) were explored and a saturating (log-) sigmoid function was deemed to be statistically the best fit. The excess mortality associated with microfilarial load was also found to be greater in younger hosts. The attributable mortality risk due to onchocerciasis was estimated to be 5.9%. CONCLUSIONS/SIGNIFICANCE: Incorporation of this non-linear functional relationship between microfilarial load and excess mortality into mathematical models for the transmission and control of onchocerciasis will have important implications for our understanding of the population biology of O. volvulus, its impact on human populations, the global burden of disease due to onchocerciasis, and the projected benefits of control programmes in both human and economic terms.