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Biomedical subjects

C S Peckham

Publications and source records attributed to C S Peckham.

At least 19 recordsLinked to original sources
PubMed2002

Congenital toxoplasmosis in the United Kingdom: to screen or not to screen?

The United Kingdom National Screening Committee recently reviewed the evidence for prenatal and neonatal screening for toxoplasma infection and concluded that there was insufficient evidence to recommend screening in the United Kingdom. This issue will need to be revisited as new information or treatments become available. In this paper, the extent to which the research evidence on toxoplasma infection meets the criteria that need to be fulfilled for the introduction of screening in the United Kingdom is reviewed.

Female↗
PubMed2000

Disclosure of diagnosis and planning for the future in HIV-affected families in Europe.

Information relating to disclosure of infection status in families affected by HIV and the existence of plans for the future social care of children with infected parents was collected as part of a larger survey on clinical and psychosocial service use of these families. Parents and alternative carers of HIV-affected children in follow-up in 10 paediatric centres from seven European countries were surveyed. A total of 182 questionnaires were returned: most (73%) were completed by parents, of whom 92% were HIV-infected. Of the 226 children cared for by the respondents, most (62%) were HIV-infected. Disclosure of both the child's and the parent's infection status was rare and found to be associated with child's age in both cases. Infected children living with their parents were less likely to know their diagnosis than those living in alternative care. Uninfected parents and carers were significantly more likely to want professional help with disclosing to an infected child than infected parents. Infected parents also face difficult decisions regarding the issue of who will care for their children when they are unable to. Half of the infected parents had made long-term plans for their children's future social care. European parents were more likely to have made such plans than those from elsewhere (mainly Africa) and parents with plans had known about their HIV infection for significantly longer than those without. Increasing numbers of vertically infected children are reaching adolescence as a result of improvements in the management of paediatric HIV infection. As both disclosure and planning for the future social care of HIV-affected children have been found to be strongly associated with child's age, the changing epidemiology of paediatric HIV highlights the need for more information on these issues in order to support families more effectively.

Adolescent↗
PubMed2000

The public health applications of unlinked anonymous seroprevalence monitoring for HIV in the United Kingdom.

BACKGROUND: In order to monitor the epidemiology of human immunodeficiency virus (HIV), integrated national programmes of unlinked anonymous (blinded) HIV sero-surveys have taken place in the UK since 1990. METHODS: The programmes comprise multi-centre surveys primarily using specimens gathered routinely for screening groups of patients. All specimens are irreversibly unlinked from patient identifiers before being tested. RESULTS: The surveys have met their prime aim of providing at low cost minimally biased estimates of current HIV prevalence and trends in sentinel populations. The surveys have remained acceptable to professionals and the public, being successfully implemented without breech of their founding principles. The findings have had major public health applications, have influenced HIV policy and funding, been used for monitoring the spread of HIV, for targeting and evaluating health promotion and improving projections of severe HIV disease. The surveys have detected substantial prevalence rises and under-diagnosis of HIV which would otherwise have been unrecognised. The programmes' value is being increased by sub-typing HIV-1 isolates, capturing additional demographic information to detect spread among minority groups. The same specimens are used for monitoring other infections (initially hepatitis A, B and C). CONCLUSIONS: Monitoring HIV and other infections through unlinked anonymous HIV surveillance has become an integral essential part of national HIV and AIDS surveillance. Although it has unique applications the value of unlinked anonymous surveillance is maximized when used in conjunction with behavioural data, information from HIV and AIDS reporting, and behavioural data and surveillance for other sexually transmitted infections.

Confidentiality↗
PubMed1998

Factors affecting uptake of antenatal HIV testing in London: results of a multicentre study.

OBJECTIVES: To measure the uptake of antenatal HIV testing and determine its relation to risk of HIV and to screening practices. DESIGN: Multicentre prospective questionnaire study. SUBJECTS: Pregnant women attending six maternity units. SETTING: Inner London, 1995-6. MAIN OUTCOME MEASURES: Uptake of testing by risk factors for HIV, ethnicity, and factors about the antenatal interview. RESULTS: All units had a "universal offer" policy for HIV testing. In five units forms were completed for 18,791 (88%) of 21,247 pregnant women. The sixth unit, where the response rate was too low to assess uptake, was excluded from the analysis. Uptake ranged from 3.4% to 51.2% (overall 22.9%), in parallel with detection of previously undiagnosed infection in pregnant women (4.9-60%). Controlling for unit, uptake was higher among the 7% who disclosed risk factors. Among those at low risk, uptake varied by ethnic group (South Asian women 9%; Latin American and Mediterranean women 33%). The relation between uptake and HIV risk category varied greatly across units. Despite increased HIV seroprevalence in black African women, uptake was similar in this group to that among women at low risk (24%). Uptake increased 2.1-fold if HIV transmission was discussed. Midwives reported spending 7 (2-15) minutes discussing HIV issues. CONCLUSIONS: Uptake of HIV testing was unacceptably low in all units, with maternity unit the strongest predictor. New approaches to antenatal HIV testing are urgently required and uptake should be audited routinely.

Africa↗
PubMed1998

Routine vaccination and vaccine-preventable infections in children born to human immunodeficiency virus-infected mothers. European Collaborative Study.

Information on vaccinations and vaccine-preventable infections collected in a prospective study of children born to human immunodeficiency virus (HIV)-infected mothers was analysed for reports of adverse reactions and to estimate the clinical efficacy of vaccines. No vaccinated, HIV-infected child developed measles (56 child-years' follow-up), mumps (33), rubella (33) or pertussis (239), and only one adverse reaction - to Bacillus Calmette-Guerin (BCG) - was reported. These findings provide limited evidence of the safety and efficacy of routine vaccination of HIV-infected children.

Chickenpox↗
PubMed1998

A review of hepatitis C virus (HCV) vertical transmission: risks of transmission to infants born to mothers with and without HCV viraemia or human immunodeficiency virus infection.

BACKGROUND: Hepatitis C virus (HCV) vertical transmission studies have reported conflicting findings, possibly due to differences in HCV transmission risk factors among maternal populations, or to methodological differences. METHODS: Systematic review of worldwide published and unpublished HCV vertical transmission studies. Standardized diagnostic criteria were applied to minimize methodological differences, and transmission rates recalculated according to maternal HCV viraemic and human immunodeficiency virus (HIV) infection status. RESULTS: In all, 976 eligible infants from 28 studies were followed up sufficiently for recalculation of transmission rates. Overall transmission rates were less than 10% in 8/12 studies of HIV negative mothers, compared with 2/7 studies comprising at least 50% HIV-coinfected mothers. Rates from 409 viraemic mothers in 15 studies ranged from 0% to 41%, being less than 10% from HIV negative mothers in 6/13 studies and from HIV positive mothers in 1/6 studies. Nine studies measured maternal viraemia levels, with only 2/30 transmitting mothers having < 10(6) copies/ml of HCV RNA. Eight transmissions were identified overall from non-viraemic mothers. Significant transmission rate variation remained after accounting for maternal viraemia and HIV coinfection, possibly due to differences in other vertical transmission risk factors, in frequencies of postnatal transmission, or residual differences in study methodologies. CONCLUSIONS: Overall, HCV transmission is largely restricted to infants born to HCV viraemic mothers, and low risks among most HIV negative mothers may be due to lower HCV viraemia levels. International agreement on standardized diagnostic criteria for HCV vertical transmission would facilitate pooling of individual findings, to allow more precise transmission estimates and further investigation of risk factors.

Adult↗
PubMed1998

Issues underlying the evaluation of screening programmes.

Screening programmes have the potential to prevent premature death and disability and to improve quality of life, but they also have the potential for harm. Identifying worthwhile screening programmes, developing the correct strategies, and implementing them effectively is no easy task. A much more critical approach to screening is now being adopted and efforts are being made to ensure that new programmes of proven benefit and which are acceptable to the public, are effectively and equitably implemented in the community. We hope that this issue will stimulate further discussion and debate.

Cost-Benefit Analysis↗
PubMed1998

Performance of antenatal HIV screening strategies in the United Kingdom.

BACKGROUND: In 1996 only 13.5% of previously undiagnosed HIV infected women were detected in pregnancy. In this study, all 265 maternity units in the United Kingdom were surveyed to determine the relation between screening strategy, uptake of testing, and detection rate. METHODS: Data on HIV screening strategy and uptake of testing were collected in 1997 by postal questionnaire. The proportion of women with previously undiagnosed HIV infection identified during pregnancy (detection rate) was calculated using data from national obstetric HIV surveillance and unlinked anonymous seroprevalence studies. RESULTS: 239 (90%) units responded; 25 of these (10%) had a universal offer strategy, 89 (37%) a selective offer, and 125 (52%) tested only women who requested it. All selective units offered testing to injecting drug users, but only 26% to women who had lived abroad in high prevalence areas. Uptake was over 10% in only eight units, all with a universal strategy, and in 76% of selective units it was below 0.1%. The detection rate was 14.7% in universal units, 7.8% in selective units, and 7.7% in on request units. In universal units, detection increased by 6.3% (95% confidence interval 3.7% to 8.8%) for every 10% increase in uptake of testing. There was evidence of both selective presentation for testing and avoidance of testing among infected women. CONCLUSIONS: All current antenatal HIV testing strategies fail to identify most infected women. Universal offer strategies achieve a very low uptake and a poor detection rate. Units with selective strategies tend to test only a minority of women at high risk and do not target all the main high risk groups.

Female↗
PubMed1997

Morbidity and mortality in European children vertically infected by HIV-1. The French Pediatric HIV Infection Study Group and European Collaborative Study.

Based on 392 infected children enrolled in two European prospective studies of infants born to HIV-infected women, with similar standard protocols, HIV disease progression in the first 6 years of life is described, using the 1994 CDC paediatric HIV classification. Most children had developed minor (A) or moderately severe (B) illness in the first 4 years of life, although usually it was transient in nature. Progression to U.S. Centers for Disease Control and Prevention (CDC) group C disease or HIV-related death is an estimated 20% (95% confidence interval 16-24%) during the first year of life, and 4.7% (3.3-6.5%) per year thereafter, giving a cumulative incidence of 36% (30-43%) by 6 years. The mortality rate at 6 years is 26% (20-32%). Two thirds of the children alive at 6 years had only minor symptoms, and one third had a CD4+ cell distribution of > 25% despite previous clinical manifestations and a transient period of moderate immune deficiency. Differences in zidovudine monotherapy between the two cohorts were not associated with the mortality rate. However, the risk of severe bacterial infections was lower in the French cohort, in which the use of antibacterial prophylaxis was more common. The early, severe form of HIV disease affects approximately 20% of infants, and after 6 years 75% of infected children are still alive. This has important implications for health-care planning.

Adult↗
PubMed1997

Use of polymerase chain reaction and antibody tests in the diagnosis of vertically transmitted hepatitis C virus infection.

Data on patterns of polymerase chain reaction (PCR) and antibody test results in infants born to hepatitis C virus (HCV)-infected mothers were systematically reviewed to aid development of optimum testing schedules and diagnostic criteria for vertically exposed infants and to facilitate early identification of infected infants. Survival and cross-sectional analyses were used to estimate the timing of initial PCR positivity and subsequent PCR negativity in infected infants, and maternal antibody loss in uninfected infants was estimated as a weighted average of individual study findings. Of 74 eligible infants with strong evidence of HCV infection, an estimated 89% (90% confidence interval, 80-95%) were first PCR positive by 3 months of age, and less than 10% had subsequent PCR negativity attributable to intermittent viraemia or resolved infection in the first 18 months of life. The negative predictive value of PCR at 3 months of age was greater than 98% at an assumed rate of 5% vertical transmission, but as low as 88% at 25% transmission. The inclusion of 22 infants, each with a single PCR-positive result, increased the estimated frequency of resolved infections but made little difference to other estimates. A minority of PCR-positive infants had periods of antibody negativity by second- or third-generation assays, and among 297 uninfected infants, maternal antibody was not detected beyond 18 months. Thus, the majority of infected infants may be persistently PCR positive from 3 months of age, and the negative predictive value of PCR at 3 months is generally high. However, poor repeatability of PCR, inadequate infant follow-up, and inclusion of postnatally infected infants limits interpretation of the pooled data. Further studies using standardised PCR methodologies are needed.

Cross-Sectional Studies↗
PubMed1997

Infections in childhood and pregnancy as a cause of adult disease--methods and examples.

Infection in childhood can occur in utero, perinatally or in postnatal life. Infections at these ages can have profound effects on anatomical structure and on developmental processes of a number of systems. These effects may lead to adult disease directly or increase the susceptibility to factors later in life. The detection of such childhood infections may be difficult once adult disease has developed. In this chapter we described the type of epidemiological evidence that might suggest such a situation and give examples of infections known to cause adult disease which illustrate these patterns.

Adult↗
PubMed1997

Uptake of interventions to reduce mother-to-child transmission of HIV in the United Kingdom and Ireland.

OBJECTIVES: To describe the uptake of interventions to reduce mother-to-child transmission of HIV infection. DESIGN: Voluntary confidential reporting of HIV infection in pregnancy and childhood; telephone interview with key professionals in all London maternity units. SUBJECTS AND SETTING: HIV-infected pregnant women and children in the United Kingdom and Ireland. MAIN OUTCOME MEASURES: Trends in breastfeeding, use of zidovudine, mode of delivery and terminations of pregnancy. RESULTS: Between 1990 and 1995, 14 (4%) out of 314 women diagnosed with HIV infection before delivery breastfed compared with 109 (77%) out of 142 diagnosed after delivery. Since 1994, zidovudine use has increased in each 6-month period (14, 39, 67, and 75%; chi 2 = 17.5, P < 0.001), although in 1995 it was the policy of only 48% of London maternity units to offer zidovudine to HIV-infected women. During 1995, 44% of HIV-infected women were delivered by elective Cesarean section. Since 1990, 20% of women first diagnosed in pregnancy were reported to have their pregnancy terminated. CONCLUSIONS: Although detection of previously undiagnosed HIV infection in pregnancy remains low in the United Kingdom, and particularly in London, HIV-infected pregnant women who are aware of their status are increasingly active in taking up interventions to reduce transmission to their infants. If all HIV-infected women attending for antenatal care in London consented to testing and took up interventions and termination of pregnancy at the rates observed in this study, the number of vertically infected babies born in London each year could be reduced from an estimated 41 to 13.

Abortion, Induced↗
PubMed1996

Neonatal herpes simplex virus infection in the British Isles.

This study was set up to estimate the incidence of neonatal herpes simplex virus (HSV) infection in the British Isles, and to document the outcome of neonatal infection. Paediatricians reported cases of neonatal HSV through the active reporting scheme of the British Paediatric Association Surveillance Unit. Over a 5 1/2 year period (1986-91) 76 infants with neonatal HSV infection were reported, an incidence of recognised infection in the British Isles of 1.65/100000 livebirths. Twenty-five infants had HSV-1 infection, 24 HSV-2 and in 27 virus type was unknown. Twenty-seven had disseminated infection, 23 herpes encephalitis and 26 localised infection. Nineteen infants (25%) died in the neonatal period, and a further 25 (33%) have subsequently died or have long-term sequelae. At least half of the infants had been discharged home before symptoms became apparent. For 21 women there was evidence of a maternal genital herpes infection at some time, but this was reported or diagnosed retrospectively after neonatal HSV was suspected in 19 cases, and antenatally in only two. Neonatal HSV is rare in the British Isles and routine antenatal screening for genital herpes infection during pregnancy is not justified. A high proportion of infected infants present with non-specific signs and symptoms and without mucocutaneous involvement; furthermore, there is rarely a history of maternal infection. As early diagnosis and prompt treatment is essential, there must be a high level of awareness of the serious nature of neonatal HSV infection.

Confidence Intervals↗
PubMed1996

Vertical transmission of HIV-1: maternal immune status and obstetric factors. The European Collaborative Study.

OBJECTIVE: To estimate the effect of maternal factors and events around the time of delivery on HIV-1 vertical transmission risk. DESIGN: Prospective study. SETTING: Twenty-two obstetric and paediatric clinics in seven European countries. PATIENTS OR OTHER PARTICIPANTS: Mothers identified as HIV-infected before or at delivery and their children. MAIN OUTCOME MEASURE: Paediatric HIV infection. RESULTS: By November 1995, 1846 mothers with 1945 children had been enrolled. The vertical transmission rate was 16.4% (95% confidence interval, 14.5-18.3). Parity, maternal age, race, mode of HIV acquisition, injecting drug use and sex of infant were not statistically significantly associated with risk of transmission. Children delivered vaginally were more likely to be infected than those delivered by Caesarean section. However, in vaginal deliveries the procedures used, duration of ruptured membranes or length of second-stage labour were not related to transmission. Transmission increased almost linearly with decreasing CD4 cell count, but there was no such trend for CD8 cell count. Women with CD4 cell counts below 200 x 10(6)/l were significantly more likely to deliver early (chi 2 for trend, 14.02; P < 0.001). Very premature infants were at increased risk of infection, but after about 35 weeks gestation the transmission rate remained stable, with no increase in late pregnancy. This trend was confirmed after allowing for maternal CD4 cell count. CONCLUSIONS: The rate of vertical transmission increases linearly with decreasing maternal CD4 cell count. Women with fewer than 200 x 10(6) CD4 cells/l have an increased risk of premature delivery, which would affect timing of interventions. The stable transmission rate after 35 weeks gestation suggests little acquisition of infection during late pregnancy.

Europe↗
PubMed1994

Use of anonymous newborn serosurveys to evaluate antenatal HIV screening programmes.

OBJECTIVE: To evaluate the extent to which antenatal HIV screening programmes identify HIV infected women who go to term. DESIGN: Comparison of results of two surveillance systems. An anonymous neonatal HIV serosurvey was used to estimate the numbers of HIV infected women giving birth; reporting by obstetricians was used to assess the proportion who had been identified. SETTING: Three Thames regions. RESULTS: 729,105 neonatal blood samples were tested, of which 484 were HIV seropositive. Newborn HIV seroprevalence is increasing, at different rates, in inner London, suburban London, and in non-metropolitan districts. During the past four years the proportion of infected women who have been identified before delivery is 16.9%, but less than half of these were diagnosed during pregnancy. In 1993 only five of the 128 (4%) previously undiagnosed infected women delivering babies were identified by antenatal screening. CONCLUSION: Despite increased emphasis on antenatal testing for HIV in areas of higher prevalence the number of undiagnosed women delivering babies continues to increase. Consideration should be given to alternative strategies for offering antenatal HIV testing. Antenatal screening programmes should be monitored continuously by comparing anonymous neonatal seroprevalence with clinical reports from obstetricians.

Confidence Intervals↗