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Biomedical subjects

M E Ramsay

Publications and source records attributed to M E Ramsay.

At least 19 recordsLinked to original sources
PubMed2006

Changes in ascertainment of Hib and its influence on the estimation of disease incidence in the United Kingdom.

Enhanced surveillance for Hib infection, initially covering Wales and five English regions, began in 1990 and in 1995 was extended to the whole of England and Wales. To determine whether changes in the ascertainment of Haemophilus influenzae may have affected estimates of Hib disease incidence, data from January 1990 to December 2003 were analysed. A total of 8887 and 4020 (45%) cases of H. influenzae and Hib respectively were reported. The proportion of isolates that were serotyped increased over time, and therefore reported incidence may have underestimated the true incidence in the early years of the study. Adjusting for this under-ascertainment, the incidence in children aged <5 years declined from a peak of 28.3/100,000 in 1991 to 0.97/100,000 in 1998 and increased to 3.8/100,000 in 2003. Following the implementation of universal vaccination a dramatic decline in the true incidence of invasive Hib disease occurred. The observation of the subsequent resurgence was real but the highest incidence reached was 85% below the corrected incidence in the pre-vaccine era. Continued high-quality surveillance is needed in order to accurately monitor and detect changes in disease incidence.

Bacterial Capsules↗
PubMed2006

Hepatitis C virus: laboratory surveillance in England and Wales, 1992-2004.

Between 1992 and 2004, a total of 49,819 confirmed hepatitis C infections have been reported to the Health Protection Agency (HPA) by laboratories in England and Wales; the annual number of reports increased from 241 in 1991 to 8149 in 2004. Most reports with a known risk factor were in injecting drug users (87%, 12,438/14,221), but 71% (35,598/49,819) of the total had no reported identified risk. The age-sex distribution of the latter cases was similar to that in injecting drug users. Using names to assign ethnicity, individuals with South Asian names had an older age distribution and a different risk factor profile from non-South Asians. Using published age-specific prevalence data from 1996, it was estimated that around 28,1764 cases of hepatitis C infection exist in England and Wales, and that only 17% of these cases have been reported to the HPA. Surveillance reports continue to provide important information regarding trends in hepatitis C infection in specific risk groups.

Adolescent↗
PubMed2006

Sentinel laboratory surveillance of hepatitis C antibody testing in England: understanding the epidemiology of HCV infection.

This paper describes sentinel laboratory surveillance of hepatitis C antibody testing in England. Demographic and test result data were supplemented by follow-up questionnaires sent to the requesting clinician. Between October 2002 and September 2003 almost 75000 anti-HCV tests were performed in eight sentinel centres. More males were tested than females and over half of those tested were aged 25-44 years. Overall 5.7% (3333/58144, range 2.8-7.7%) individuals tested positive. Follow-up questionnaire data showed that 82% (1043/1277) of the positives had injecting drug use reported as the main risk exposure. The majority of negative individuals were undergoing routine screening as recommended for specific patient groups. Most individuals were asymptomatic. Antibody prevalence was estimated to be 34% in current injecting drug users and 42% in former injectors. Comparing positives to routine national surveillance suggests that only 53% (1782/3333) of diagnosed cases were reported. Sentinel laboratory data can provide valuable supplementary data to national surveillance.

Acute Disease↗
PubMed2006

Investigating the aetiology of and evaluating the impact of the Men C vaccination programme on probable meningococcal disease in England and Wales.

The aims were to (1) investigate the aetiology of probable meningococcal disease, where a clinical diagnosis is made in the absence of laboratory data, and (2) evaluate the impact of the Men C vaccination programme in England and Wales. Multiple linear regression analyses were carried out using data reported to Enhanced Surveillance of Meningococcal Disease (ESMD) and laboratory reports of isolates of organisms causing symptoms that mimic meningococcal disease. Confirmed meningococcal disease appeared to be a significant predictor of probable disease. Thus, an additional reduction in meningococcal disease attributable to the serogroup C vaccination campaign was evident in probable disease over and above that observed in confirmed cases alone. Enteroviruses were a significant contributor to cases of probable meningitis and influenza appeared to be a significant contributor to probable cases of septicaemia. This analysis confirms the success seen following the Men C vaccination campaign and gives an indication of the aetiologies of other causes of probable meningitis and septicaemia reported to ESMD.

Adolescent↗
PubMed2005

Changes in the epidemiology of epiglottitis following introduction of Haemophilus influenzae type b (Hib) conjugate vaccines in England: a comparison of two data sources.

Paediatric cases of epiglottitis declined markedly in England following the introduction of safe effective immunization against Haemophilus influenzae type b (Hib). With the recently described resurgence in Hib infections, a corresponding rise in the number of presentations of clinical epiglottitis in children was observed, although numbers were still well below those reported prior to vaccine availability. This was seen both in microbiology reports and hospital admissions data for England. In keeping with the more diverse aetiology of epiglottitis in adults, Hib vaccination had minimal impact on hospital presentations with upper airway infections in those aged 15 years and over, which showed an overall increasing trend over 10 years. The need for a high index of suspicion to allow early diagnosis of this life-threatening clinical presentation is reinforced.

Adolescent↗
PubMed2005

Survival of a national cohort of hepatitis C virus infected patients, 16 years after exposure.

The aim of this study was to describe the natural history of HCV after 16 years of infection, in a cohort of individuals who acquired their infections on a known date in the United Kingdom. A total of 924 HCV-infected transfusion recipients (cases) and 475 anti-HCV negative transfusion recipients (controls) were eligible for inclusion in the study. Survival was compared between cases and controls to see if there was any excess mortality attributable to HCV. The results show that all-cause mortality was not significantly different between cases and controls (hazard ratio 1.17, 95% CI 0.92-1.49, P=0.21). However, the risk of death directly from liver disease was higher in cases than controls (hazard ratio 2.71, 95% CI 1.09-6.75, P=0.03). Nearly 30% of those HCV-infected cases who died directly from liver disease were known to have consumed excess alcohol.

Adolescent↗
PubMed2005

Effect of different immunisation schedules on the excretion and reversion of oral poliovaccine strains.

Excretion of live oral poliovaccine and molecular markers of increased virulence in the viruses isolated were examined in children who were either previously immunised with inactivated or live vaccine or were unimmunised. There appeared to be some effect of previous immunisation with either live or killed vaccine at the second dose of live vaccine. Where an effect was seen it took the form of reduced rates of excretion, shorter time periods of excretion and more rapid and complete reversion of the excreted virus. The data are consistent with the view that poliovirus is able to escape the immune pressure in the gut to some extent by improving its general fitness rather than direct evasion of immunity.

5' Untranslated Regions↗
PubMed2005

Pathways of care and resource utilization in a national cohort of patients with transfusion-acquired hepatitis C.

The Hepatitis C Strategy and Action Plan for England recommend that all individuals testing positive for hepatitis C virus (HCV) should be referred to a specialist centre for assessment and care. One key aim is to reduce the number of people progressing to liver disease and therefore reduce the associated costs. The aims of this paper are to describe the care pathways and evaluate resource utilization in a cohort of 826 patients with transfusion-acquired hepatitis C enrolled in the HCV national register. We reviewed data extracted from patient notes to establish pathways of care since HCV-positive diagnosis through to May 2002, and to document all treatment, liver biopsy and hospital usage for each patient. Type of care was classified into specialist-interest in HCV-related care, other-hospital care or general practitioner (GP)-led care. Over 70% of patients were referred to specialist care following HCV diagnosis. Patients who were older or who had normal liver function were less likely to be referred to specialist-care. Between first diagnosis and May 2002, no patients were referred from GP to specialist-care. Less than half of this cohort had undergone liver biopsy and only 18% had been treated. Younger patients and those with abnormal liver function were more likely to have undergone liver biopsy and to have received treatment. Analysis of care histories of patients with transfusion-acquired hepatitis C suggest that changes are needed in the care and management of patients with HCV infection, if the recommendations of the HCV strategy and action plan are to be fully implemented.

Adult↗
PubMed2004

Long-term impact of vaccination on Haemophilus influenzae type b (Hib) carriage in the United Kingdom.

A recent resurgence in serious infections due to Haemophilus influenzae type b (Hib) has been observed in the United Kingdom. More information on Hib transmission in the population is required in order to better understand the mechanism of this increase. The Public Health Laboratory Service (subsumed into the Health Protection Agency since April 2004) conducted four cross-sectional studies of asymptomatic oropharyngeal Hib carriage in children attending day-care nurseries in England and Wales in 1992, 1994, 1997 and 2002. These demonstrated a marked reduction in the prevalence of Hib colonization over time since vaccine introduction (3.98% in 1992; 0.70% in 1994; 0% in 1997; 0% in 2002), which did not explain the increase in invasive disease reports from 1999 onwards. We believe that a reduction in antibody levels over the first 5 years of life in immunized children in recent years has fuelled the rise in reported cases in the absence of an obvious increase in transmission.

Child Day Care Centers↗
PubMed2004

Clusters of meningococcal disease in school and preschool settings in England and Wales: what is the risk?

AIMS: To assess the risk of further cases in educational settings in order to inform policy on managing cases and clusters of meningococcal disease. METHODS: Between 1 April 1995 and 31 March 2001, surveillance in preschool and school settings in England and Wales identified 114 clusters of meningococcal disease. Twenty clusters were reported in preschool settings, 43 in primary, 46 in secondary, and five in independent schools. Seventy three clusters (64%) consisted of two or more confirmed cases, of which 30 had two or more serogroup C cases. Following the introduction of the national meningococcal serogroup C vaccination programme in 1999, no serogroup C clusters were observed between April 2000 and March 2001. RESULTS: The relative risk of further cases in the four weeks after a single case compared with the background rate was raised in all settings, ranging from RR 27.6 (95% CI 15.2 to 39.9) in preschool settings to RR 3.6 (95% CI 2.5 to 4.6) in secondary schools. Absolute risk estimates ranged from 70/100 000 in preschool settings to 3.0/100 000 in secondary schools. The relative risk of clustering was similar for serogroup B and C strains. Most (68%) second cases occurred within seven days of the first case. CONCLUSIONS: Although there was a higher risk of further cases of meningococcal disease in schools and especially in preschool settings, it is not known whether widespread antibiotic use after single cases reduces risk of further cases and if there is a real risk of harm. Evidence of risk reduction is needed to inform public health policy.

Child↗
PubMed2003

Risk of vaccine failure after Haemophilus influenzae type b (Hib) combination vaccines with acellular pertussis.

An increase in invasive Hib disease incidence in the UK has coincided with the distribution of combination vaccines that contain acellular pertussis (DTaP-Hib). These vaccines have been associated with reduced immunogenicity of the Hib component, although there is little agreement on the clinical relevance of this finding. We retrospectively compared vaccine formulations given to fully vaccinated Hib cases with those administered to fully immunised age-matched controls using conditional logistic regression. More cases than controls received all three doses of their infant primary course as DTaP-Hib, compared with two or three doses of another Hib vaccine (conditional odds ratio 6.77 [95% CI 3.26-14.07]).

Diphtheria-Tetanus-Pertussis Vaccine↗
PubMed2003

Antibody to Haemophilus influenzae type b after routine and catch-up vaccination.

Since 1999, the number of cases of Haemophilus influenzae type b (Hib) disease in the UK has risen. We investigated the role of population immunity in this change by testing more than 2600 serum samples from children aged 1-15 years. After the introduction of the routine Hib conjugate vaccination programme for infants, median antibody titres rose significantly in 1-year-olds. Individuals who received their first dose of vaccine at age 1-4 years in the original catch-up campaign initially had much higher concentrations of antibody than those who had been immunised in infancy. A second catch-up campaign in children aged 6 months to 4 years should be highly effective in boosting immunity and reducing disease in the short term.

Adolescent↗
PubMed2003

Tetanus in England and Wales, 1984-2000.

A review of national tetanus surveillance in England and Wales during 1984-2000 was undertaken to evaluate the surveillance system and national vaccination policy. Hospital Episode Statistics for tetanus in England for fiscal years 1989/90-1995/6 were also examined to estimate under-reporting. A total of 175 cases of tetanus were reported, giving an annual incidence of 0.20 per million, the lowest levels ever recorded. The highest incidence was in those aged over 64 years (0.66 per million) with no significant sex difference. Twenty (11%) cases were reported in people who were eligible for routine childhood vaccination. Outdoor injuries were the commonest reported exposure risk. Tetanus case under-reporting was estimated as 54-64%. We conclude that GPs should ensure that all their patients are fully vaccinated, targeting those born before 1961. High childhood tetanus vaccination coverage remains a priority. As the disease becomes rarer, enhanced tetanus case surveillance is essential for tetanus immunization policy evaluation.

Adolescent↗
PubMed2003

Estimation of the risk of hepatitis B virus, hepatitis C virus and human immunodeficiency virus infectious donations entering the blood supply in England, 1993-2001.

BACKGROUND AND OBJECTIVES: The frequency of hepatitis B virus (HBV), hepatitis C virus (HCV) or human immunodeficiency virus (HIV) infectious donations entering the blood supply in England is too low to monitor using observational studies. The expected frequency of infectious donations can be estimated and these estimates may be used to contribute to monitoring of blood safety and used in the design of strategies to decrease the risk of transfusion-transmitted infections. MATERIALS AND METHODS: The prevalence and incidence of hepatitis B surface antigen (HBsAg), and antibodies to HCV and HIV (anti-HCV and anti-HIV, respectively) in donors in England, between 1993 and 2001, were used together with data about the length of negative 'window-periods' of current assays for each of these markers and data about test performance, to estimate the number of infectious donations that enter the blood supply. The risks were calculated separately for donations from new donors and from repeat donors, and for the three time periods 1993-95, 1996-98 and 1999-01. RESULTS: The estimated frequency of infectious donations entering the blood supply in England, between 1993 and 2001 was 1 in 260,000 for HBV and 1 in 8 million for HIV. For HCV, the frequency of infectious donations was 1 in 520,000 during 1993-98 and fell to 1 in 30 million during 1999-2001 when all donations were tested for HCV RNA. The frequency of HBV- and HCV-infectious donations entering the blood supply fell over these 9 years: the frequency of HIV-infectious donations remained essentially unchanged. The risk from donations from new donors was found to be approximately sevenfold higher than the risk from donations from repeat donors. CONCLUSIONS: The risks of HBV-, HCV- or HIV-infectious donations entering the blood supply in England are very low, and have decreased since 1993. Although the accuracy of these estimates is imperfect, mainly owing to uncertainty in some assumptions and to small numbers of infections, they provide some quantification of the risk of HBV, HCV or HIV transmission by transfusion, and allow comparison of the magnitude of these risks for each infection and over time. The methods we have used have been developed and improved from previously published methods.

Blood Donors↗
PubMed2003

Hib vaccination in infants born prematurely.

AIMS: To document the immunogenicity and persistence of antibody to polyribosyl-ribitol phosphate (PRP) as well as the clinical protection against invasive Haemophilus influenzae type b (Hib) disease in premature infants immunised at the routine schedule. METHODS: Blood was obtained at 2, 5, 12, and 64 months of age from a cohort of prematurely born infants (<or=32 weeks gestation). Anti-PRP antibody concentrations were compared with those of a control cohort of infants born at full term and vaccinated at the same schedule. Hib vaccine failures occurring between October 1992 and October 2000 were reported by paediatricians through an active, prospective, national survey in the UK and Republic of Ireland. The number of prematurely born children with vaccine failure was compared with the corresponding number born at term. RESULTS: Twenty seven prematurely born infants were followed to 5 years of age. Compared with term infants they had a significantly lower geometric mean concentration of anti-PRP antibody and/or a significantly lower proportion above one or both of the conventional protective antibody concentrations (0.15 and 1.0 micro g/ml) at all ages. A total of 165 cases of invasive Hib disease were identified over eight years of national surveillance. Eighteen were premature (<37 weeks); approximately 12 would be expected. The relative risk of UK premature infants developing disease compared with term infants was 1.5 (95% CI 0.9 to 2.6). CONCLUSIONS: Premature infants develop lower antibody concentrations than term infants following Hib conjugate vaccination. Premature infants may also have an increased risk of clinical vaccine failure, but interpretation is limited by the small number of premature infants developing invasive Hib disease over eight years of national surveillance. Overall, vaccination with Hib conjugate vaccines affords a high level of protection to premature babies.

Antibodies, Bacterial↗
PubMed2003

A national survey of genitourinary medicine clinic attenders provides little evidence of sexual transmission of hepatitis C virus infection.

OBJECTIVE: To determine the prevalence and genetic diversity of hepatitis C virus in genitourinary medicine clinic attenders and to assess the extent of sexual transmission of the virus. METHODS: A cross sectional, unlinked, anonymous survey in 14 genitourinary medicine clinics situated in England, Wales, and Northern Ireland. Serum specimens from genitourinary medicine clinic attenders, retained as part of the Unlinked Anonymous Prevalence Monitoring Programme (UAPMP) serum archive, were tested in small pools, for the presence of antibody to hepatitis C virus (anti-HCV). The main outcome measures were prevalence of antibodies to hepatitis C virus and identification of hepatitis C virus genotypes. RESULTS: Testing of 17,586 specimens from 1995 showed an adjusted prevalence of anti-HCV in genitourinary medicine clinic attenders of 1.03% (95% CI: 0.89 to 1.16) overall and 0.65% (95% CI: 0.51 to 0.78) among those who did not report injecting drug use. Prevalence in injecting drug users attending genitourinary medicine clinics was 36.9% in both 1995 and 1996. Heterosexual injecting drug users had a higher prevalence of anti-HCV than homosexual/bisexual injectors. The most common hepatitis C genotypes were types 3a and 1a. There was a high degree of concordance between genotype and serotype. CONCLUSIONS: The low prevalence of anti-HCV in genitourinary medicine clinic attenders who deny injecting drugs suggests that the majority of hepatitis C infections have been acquired in adult life, mostly by injecting drug use, and that the hepatitis C virus is rarely transmitted sexually. The use of needle exchanges may explain the relatively low prevalence observed in the injecting drug users.

Adult↗