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Biomedical subjects

C Peckham

Publications and source records attributed to C Peckham.

At least 37 records · Page 2Linked to original sources

The epidemiology of rubella in England and Wales before and after the 1994 measles and rubella vaccination campaign: fourth joint report from the PHLS and the National Congenital Rubella Surveillance Programme.

The national immunisation campaign carried out in the United Kingdom in November 1994 was designed to give children aged 5 to 16 years of age a single dose of a combined measles and rubella vaccine. Its main objective was to prevent an epidemic of measles predicted in school age children. The rubella component of the vaccine was included in order to reduce the high level of susceptibility to rubella in young adult males and thus reduce the risk of transmission from this group to pregnant women. Susceptibility to rubella in children aged 5 to 16 years has fallen from 15.7% to 3.4% since the measles and rubella campaign. Despite this the incidence of laboratory confirmed rubella rose substantially in 1996, largely on account of cases among males aged 17 to 24 years, who were not vaccinated in the 1994 campaign and about 16% of whom are susceptible. The impact of the resurgence on the incidence of infection in pregnancy has been relatively limited, due to the low level of susceptibility in the antenatal population (2% in nulliparous and 1.2% in parous women for 1994/5). No cases of congenital rubella arising from administration of measles and rubella vaccine during the campaign have been identified. The numbers of babies born with congenital rubella and terminations of pregnancy for rubella arising from the 1996 resurgence are expected to be similar to those that followed the 1993 resurgence. The reduction in susceptibility in future cohorts of young men who received measles and rubella vaccine in the 1994 campaign should prevent future resurgences after the year 2000. If a second dose of measles, mumps, and rubella (MMR) vaccine had not been introduced, susceptibility levels in the school age population would have risen to about 12% in the future. The effect of the second dose of MMR vaccine introduced for children aged 4 to 5 years in October 1996 will be assessed through serological surveillance.

Adolescent↗

Human immunodeficiency virus infection and mode of delivery.

Most children acquire human immunodeficiency virus (HIV) infection vertically from an infected mother. Indirect evidence suggests that a substantial proportion of infection is acquired around the time of delivery, which suggests that this would be an appropriate time to intervene. If intrapartum transmission of HIV occurs primarily through direct exposure of the infant to cell-associated or free HIV in genital secretions or blood during passage through the birth canal, or by ascending infection, caesarean section performed prior to labour might reduce the risk of transmission. There is insufficient evidence to justify routine caesarean section deliveries for HIV-infected women, and a randomized clinical trial of mode of delivery has started in Europe.

Cesarean Section↗

Characteristics of pregnant HIV-1 infected women in Europe. European Collaborative Study.

There is a growing number of infected women in Europe and an increasing proportion of these have acquired their infection through heterosexual contact. Most infected women are of childbearing age and thus increasing numbers of children are at risk of acquiring infection. In this paper we examine the socio-demographic characteristics and trends in mode of acquisition of infection of 1690 infected women from 7 countries enrolled in the European Collaborative Study, a prospective multi-centre study of children born to women known to be HIV infected at or before the time of delivery. The majority of women were white, primiparae, married or cohabiting and born in Europe. Two-thirds had a history of injecting drug use (IDU), most commonly involving heroin. Although patterns of transmission varied by centre, there was a relative increase in heterosexual transmission over the study period. A history of needle-sharing among IDUs was common, but needle-sharing during pregnancy significantly declined between 1987 and 1994.

Adult↗

Adult outcome of normal children who are short or underweight at age 7 years.

OBJECTIVES: To evaluate the adult growth outcome (at age 23) of children who are short or underweight at age 7 years in whom no identifiable pathological cause exists for their poor growth. DESIGN: Longitudinal follow up of a birth cohort. SETTING: The national child development study (1958 birth cohort) of Great Britain. SUBJECTS: 523 children with a height or a weight below the fifth centile at age 7. Of these, 70 (13.4%) were excluded because they had a longstanding illness that could account for their poor growth. The remaining 453 subjects, who were followed to age 23, provided the base group from which those with additional data, such as parental height, were obtained. RESULTS: 55/174 (31.6%) boys who were short at age 7 became short men; 60/211 (28.4%) girls who were short at age 7 became short women. Among boys who were underweight at age 7, 46/160 (28.7%) were still underweight at age 23, while 61/200 (30.5%) girls underweight at age 7 became underweight women. Having short parents did not increase the probability of being small as an adult. Children with delayed puberty were as likely to remain small as those in whom puberty was not delayed. CONCLUSIONS: One in three normal children who was short or underweight at age 7 became a short or underweight adult. This informs the management of short children and may be valuable when prolonged growth hormone treatment for short stature is being considered.

Adolescent↗

Use of polymerase chain reaction and quantitative antibody tests in children born to human immunodeficiency virus-1-infected mothers.

The diagnosis of human immunodeficiency virus (HIV) infection in children born to HIV-infected mothers is complicated by the presence of passively acquired maternal antibodies, and exclusion of infection in these infants remains problematic. The use of genome detection by polymerase chain reaction (PCR) amplification and the quantification of anti-HIV-1 antibodies were examined as methods for early diagnosis. Blood samples were taken from 84 non-breast-fed infants of HIV-infected mothers in five Italian and Spanish centres, a subgroup of children enrolled in the European Collaborative Study (ECS) for whom clinical and immunological information has been documented from birth. Whole blood was added to glycigel cryopreservative, stored, and tested in the United Kingdom by a nested PCR method. Antibody to HIV-1 was detected and quantified by titration using a gelatin particle agglutination test. PCR sensitivity and specificity were assessed. Twenty-one of the 84 children tested were infected. The estimated PCR sensitivity ranged from 0% (95% CI 0-26%) on day 1, 57% (19-85) on day 7, to 63% (33-92) on day 30. The negative predictive value of PCR ranged from 85% (83-88) on day 0 to 98% (94-100) at 3 months of age. On average, the level of maternal antibody halved every 33 days (31-36.5) in uninfected children. Between 6 and 9 months of age, increases in antibody titres in infected children were not more informative than absolute levels. These findings suggest that antibody measurement may supplement genomic diagnosis and that this collection method provides an alternative to the use of dried blood spots.

Age Factors↗

The European Collaborative Study: clinical and immunological characteristics of HIV 1-infected pregnant women.

OBJECTIVE: To describe the changing clinical and immunological characteristics and timing of diagnosis of HIV-infected pregnant women enrolled in the European Collaborative Study. DESIGN: A prospective study of the mothers of children enrolled in the European Collaborative Study on children born to HIV-infected women. SETTING: Twenty-one European centres in seven countries. SUBJECTS: One thousand six hundred and ninety HIV-infected women and their 1754 deliveries. RESULTS: The proportion of women in whom HIV infection had been diagnosed before pregnancy increased significantly over time, from 7% in 1984-1985 to 65% in 1994 (P < 0.001). The prevalence of breastfeeding, which was related to the timing of diagnosis, significantly declined over the study period. The mean CD4 count was 510 cells/mm3, and there was a significant decline in average CD4 count over the study period. Black women had a significantly lower CD4 count than white women. From survival analysis it is estimated that five years after delivery 14% of women will have died and 24% will have developed CDC stage IV disease. CONCLUSIONS: Timing of diagnosis is of critical importance if mother-to-child transmission is to be reduced through avoidance of breastfeeding and zidovudine therapy and effective antenatal screening policies have become increasingly important. The rate of progression of maternal disease highlights the implications of HIV infection for their children, both infected and uninfected.

Antiviral Agents↗

Use of dried blood spots for the detection and confirmation of HTLV-I specific antibodies for epidemiological purposes.

AIMS--To modify and evaluate a gelatin particle agglutination test that could provide a sensitive, specific and inexpensive method for the detection of HTLV-I antibody in dried blood spot samples (DBS) collected on filter paper. METHODS--A set of 26 reference samples confirmed as HTLV-I antibody positive were assembled from patients with tropical spastic paraparesis or adult T cell leukaemia and blood donors. Serum samples and simulated antibody positive dried blood spot eluates were tested using the Serodia assay together with two confirmatory tests: HTLV BLOT 2.3, a western blot, and Select-HTLV, an enzyme immunoassay (EIA). Both confirmatory tests use synthetic peptides to differentiate between antibodies to HTLV-I and -II. The modified Serodia assay was then used to test anonymously 10,135 DBS collected from neonates from London. Samples reactive in the modified Serodia test producing a positive result were titrated to an end point and confirmed as before. RESULTS--All 26 eluates made from simulated DBS derived from positive reference samples were identified as positive by the modified Serodia HTLV-I test and were confirmed as anti-HTLV-I positive by EIA. Two eluates derived from relatively low titre reference samples gave indeterminate results on western blotting. Screening of the 10,135 neonatal DBS resulted in six repeat reactives, five of which were confirmed. The remaining reactive sample gave an indeterminate result on western blotting and there was insufficient eluate for testing by EIA. The overall seroprevalence of HTLV-I in this population was 0.05% (five of 10,135). CONCLUSION--The modified Serodia HTLV-I assay provides a sensitive, specific and inexpensive (10 pence/test) method for screening large numbers of DBS. The format of the assay makes it ideally suited for simultaneous screening of antibodies to HIV-1, HIV-2 and HTLV-I using semi-automated equipment.

Adult↗

Rubella surveillance to June 1994: third joint report from the PHLS and the National Congenital Rubella Surveillance Programme.

A downward trend in the incidence of acquired rubella in England and Wales was reversed in 1993 when there were local outbreaks. These affected young adult males in particular, especially those living in college residences. Some spread to local antenatal populations occurred. Twenty-five confirmed infections were reported in pregnant women, most of whom were young and in their first pregnancy; this compares with totals of 12 and two in 1991 and 1992, respectively. Reports of congenital rubella have not risen since the 1993 outbreaks. Diagnosis lags behind birth, however, and further evaluation may be needed. Notifications of 14 infants, including one set of triplets, born with congenital infection since the beginning of 1991 have been received. Nine of the 12 mothers were immigrants, and three of these acquired their infection abroad. Data on antibody prevalence have revealed a large pool of susceptible males aged 10 to 25 years, which indicates that outbreaks in males would continue for some years if no action were taken. The national measles and rubella vaccination campaign in schools this month should abolish the difference in susceptibility between boys and girls up to 16 years of age and hasten progress towards the interruption of rubella transmission in the United Kingdom. Susceptibility in girls aged 13 to 14 years rose to 5.8% in 1993 from an average of 3.6% between 1986 and 1992. This suggests that the vaccination of schoolgirls has recently declined, but this component of the selective rubella vaccination programme will be discontinued after the measles and rubella campaign.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Vertical transmission of HIV infection.

Transmission of HIV infection from mother to child may occur before, during or after delivery. Estimates of the rate of vertical transmission range from 15-20% in Europe to 25-35% in Africa. Mother-to-child transmission is associated with progression of disease in the mother, severe prematurity and breastfeeding. The association with mode of delivery needs further investigation. Attention is now being given to intervention to reduce mother-to-child transmission of HIV infection.

Africa↗

Longitudinal follow-up studies.

A longitudinal study should be undertaken only when there is a clear reason to justify this and a reasonable chance of achieving the objectives. A multidisciplinary approach is often required, and continuity of staff and long-term collaboration with colleagues are important for their success. A longitudinal approach is required to estimate the prevalence of an infection in pregnancy and the rate of vertical transmission and to clarify the natural history in infected children. An example of cytomegalovirus infection is given; the parallels with HIV are obvious.

Adult↗

Estimating the rate of mother-to-child transmission of HIV. Report of a workshop on methodological issues Ghent (Belgium), 17-20 February 1992. The Working Group on Mother-to-Child Transmission of HIV.

PURPOSE: In the last 8 years, numerous cohort studies have been conducted to estimate the rate of mother-to-child transmission (MTCT) of HIV. Many of these have faced problems in data collection and analysis, making it difficult to compare transmission rates between studies. This workshop on methodological aspects of the study of MTCT of HIV-1 was held in Ghent (Belgium) in February 1992. STUDY SELECTION AND DATA EXTRACTION: Fourteen teams of investigators participated, representing studies from Central (five) and Eastern Africa (three), Europe (two), Haiti (one) and the United States (three). A critical evaluation of the projects was carried out, under four headings: (1) enrollment and follow-up procedures, (2) diagnostic criteria and case definitions, (3) measurement and comparison of MTCT rates and (4) determinants of transmission. RESULTS OF DATA ANALYSIS: Reported transmission rates ranged from 13 to 32% in industrialized countries and from 25 to 48% in developing countries. However, no direct comparisons could be made because methods of calculation differed from study to study. Based on this review, a common methodology was developed. Agreement was reached on definitions of HIV-related signs/symptoms, paediatric AIDS and HIV-related deaths. A classification system of children born to HIV-1-infected mothers according to their probable HIV infection status during the first 15 months of life, allowed the elaboration of a direct method of computation of the transmission rate and of an indirect method for studies with a comparison group of children born to HIV-seronegative mothers. This standardized approach was subsequently applied to selected data sets. CONCLUSIONS: The methodology can now be applied to all studies with sufficient follow-up and comparisons made between transmission rates. This step is essential for assessing determinants of transmission and for the development of a common approach for the evaluation of interventions aimed at reducing or interrupting MTCT of HIV.

Adult↗

The association of formula samples given at hospital discharge with the early duration of breastfeeding.

Conflicting results have been reported regarding the association of formula samples given at hospital discharge with breastfeeding duration. This study investigated the relationship between the distribution of formula samples and breastfeeding duration in low-income Hispanic women. A gift pack of formula was distributed randomly to 88 breastfeeding women. All women received a telephone call at one and three weeks to collect information about infant feeding. Chi-square analysis revealed no significant difference in the proportion of women exclusively breastfeeding at one week. However, fewer women were exclusively breastfeeding in the gift pack group at three weeks (p less than .004). Gift packs given to Hispanic breastfeeding women are associated with a decrease in exclusively breastfeeding during the first three weeks postpartum.

Academic Medical Centers↗