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F T Cutts

Publications and source records attributed to F T Cutts.

68 records · Page 4Linked to original sources
PubMed1991

Principles of measles control.

WHO's Expanded Programme on Immunization has significantly helped to reduce global morbidity and mortality from measles. Recently, some African countries with high vaccine coverage levels have reported measles outbreaks in children above the current target age group for immunization. Outbreaks such as these are to be expected, unless close to 100% of the population are immunized with a vaccine which is 100% effective. Success of an immunization programme requires identification of the distribution and ages of susceptible children and reduction of their concentration throughout the community. Priority should be given to urban and densely populated rural areas. In large urban areas, high coverage of infants must be achieved soon after the age at which they lose their maternal antibodies and become susceptible. This will be facilitated by the introduction of high-dose measles vaccines which can be given at 6 months of age. Where measles incidence is increasing among children aged over 2 years, immunization of older children may be considered during contacts with the health care system, or at primary school entry, if this does not divert resources from immunization of younger children. Health workers should be informed of the predicted changes in measles epidemiology following immunization. The collection, analysis and use of data on measles (vaccine coverage, morbidity and mortality) should be improved at all levels of the health care system in order to monitor the immunization programme's overall impact, identify pockets of low coverage, and allow early detection of and response to measles outbreaks.

Africa↗
PubMed1990

Field evaluation of measles vaccine efficacy in Mozambique.

Monitoring measles vaccine efficacy is an important form of quality control in immunization programs. Retrospective cohort studies of vaccine efficacy were conducted in Mozambique with the aim of adopting this method for regular use. The authors studied 1,215 and 790 children aged 12-35 months in the cities of Nampula and Beira, respectively. In Nampula (1985), vaccine efficacy was estimated to be 40%, and in Beira (1986), it was estimated to be 59%. To investigate the possibility of falsely low results due to poor specificity of maternal reporting of measles cases, a seroepidemiologic study of 600 children aged 12-47 months was conducted in Nampula in 1986. The specificity and sensitivity of a maternal history of measles in an unvaccinated child were estimated as 83% and 56%, respectively. These results were used to obtain an adjusted vaccine efficacy estimate of 66%, almost double the estimate of 37% obtained using data on history of vaccination and illness alone. The large bias introduced into the vaccine efficacy estimation by low specificity of disease diagnosis is a serious limitation to the use of retrospective cohort methods to assess efficacy.

Child, Preschool↗
PubMed1990

Door-to-door canvassing for immunization program acceleration in Mozambique: achievements and costs.

The Expanded Program on Immunization has made remarkable progress in raising coverage in developing countries. Countries have been urged to accelerate their programs, especially in urban areas. In Mozambique, as part of program acceleration, volunteers from grassroots organizations conducted door-to-door canvassing for the Program. Concurrently, the availability of immunization was increased in health centers and in outreach visits. By 1987, over 90 percent coverage for all vaccines was achieved in the capital, Maputo; two other cities doubled their immunization coverage to over 50 percent fully immunized children, and rural areas of the pilot province achieved 60 percent coverage. Immunization costs were estimated in one city as $6.9 (U.S. dollars) per fully vaccinated child. Door-to-door canvassing accounted for more than 40 percent of personnel costs, and may have diverted attention from the quality of service in the health centers. In this article we outline the achievements and costs of door-to-door canvassing and discuss other strategies to raise coverage. The analysis of the need to balance the mobilization of demand with the capacity to respond is relevant to other countries in their efforts to develop sustainable immunization services.

Cost-Benefit Analysis↗
PubMed1990

Application of multiple methods to study the immunization programme in an urban area of Guinea.

During 1988-89, studies were conducted to evaluate the immunization system in Conakry, Guinea. The first, a health facility survey, found that health staff screened the vaccination status of only 30% of children who presented for curative care. A sterile syringe and needle were used for less than half of the injections. In the second survey, key informant interviews with vaccinators and health centre chiefs showed that there were minimal lines of communication between health workers and the community, but that health workers did not perceive this to be a problem. Focus group discussions in the community revealed a high level of general knowledge about vaccine-preventable diseases. However, mothers did not know how many vaccinations their children should receive or by what age they should be completed. They complained of long waiting times in health centres, the high costs of vaccination, poor rapport with health workers, and the occurrence of abscesses after vaccination. The final study, a "knowledge, attitudes, and practice" community survey, showed that missed immunization opportunities and inappropriately timed vaccinations reduced potential vaccine coverage by almost 30% among children with vaccination cards. Higher socioeconomic status, delivery in hospital, and whether mothers perceived the vaccinations to be affordable affected whether the child began the immunization series. Once a child had entered the immunization system, completion of the series was determined by the mother's education level, employment status, and experience with vaccination services.

Adult↗
PubMed1989

Evaluation of factors influencing vaccine uptake in Mozambique.

A pulse immunization project was started in Mozambique to compensate for the decrease in routine immunization caused by destabilization. A study was conducted to evaluate the project and identify determinants of vaccination in urban and rural areas of Mozambique. Vaccine coverage based on a documented record, the 'Road to Health' card, was 53% in urban and 60% in rural project areas, and 12% higher if a verbal history of vaccination was considered. A further 17% of children would have received effective vaccination if the correct schedule had been followed for all vaccines given and all preventive health services contacts had been used for vaccination. Factors relating to the individual mother and child and factors relating to the clusters were investigated for their association with vaccine uptake. Those which showed a strong negative association included vaccination on offer at the nearest vaccination post for only a small number of days per week; cancellation of an outreach session; knowing a child with a post-vaccination abscess; child born at home; at least five children in the family; mother's inability to speak Portuguese and her inability to name at least two target diseases. Improving the supervision of health services and immunizing at least three days per week at permanent immunization clinic sites may be the most important measures to improve coverage further.

Adult↗
PubMed1988

The use of the WHO cluster survey method for evaluating the impact of the expanded programme on immunization on target disease incidence.

A study was performed in Quelimane City, Mozambique, using the WHO EPI cluster sampling methodology to assess its applicability for evaluating the impact of the programme on target disease incidence rates in urban areas. Though the methodology was straightforward to use, difficulties were experienced in the retrospective diagnosis of the target diseases, which were felt to limit the reliability of the data obtained. Though results of measles incidence and mortality rates were useful to compare with routine data and discuss with local health staff, the variation in measles incidence rates between epidemic and non-epidemic years may make repeated surveys of this type inappropriate for evaluating programme impact, as it would be difficult to attribute any reduction found in one particular year to immunization and not to the variation in disease incidence which is known to occur in the absence of vaccination. It is suggested that resources would be more profitably used in establishing sentinel sites and improving the quality and utilization of routine data than in conducting repeated sample surveys.

Child, Preschool↗
PubMedDate not supplied

Prevalence of measles antibody among children under 15 years of age in Santa Cruz, Bolivia: implications for vaccination strategies.

We conducted a community-based survey in Santa Cruz city, Bolivia, to determine the age-specific prevalence of measles antibodies, determine factors associated with absence of detectable measles antibodies, and to compare results of salivary and serum measles immunoglobulin G (IgG) antibody assays. Serum samples from 1654 children were assayed for measles IgG antibody using the haemagglutination inhibition (HI) assay, and salivary samples were also obtained from 187 children and tested for measles IgG antibody using an antibody capture radioimmunoassay. Reported measles vaccine coverage in children aged 12-35 months was 77% (95% confidence interval [CI], 72-81%). Eighty-seven percent (95% CI 85-89%) had detectable HI antibody, but a high proportion had antibody levels below 200 miu (30-40% of 2-14 years old children). Measles seronegativity was associated with not being vaccinated against measles, a negative history of measles disease, living in the inner city, being a lifetime resident of Santa Cruz, and young age. Of 212 children without detectable measles antibody, 58% had a positive history of vaccination or measles disease, so that historical information was not sufficiently reliable to identify susceptibles. The salivary measles antibody assay was not sufficiently sensitive to be used for population screening; only 54% of 171 salivary samples from children who had detectable serum HI antibody were positive. A mass measles vaccination campaign of all children under 15 years of age is planned in Bolivia in 1994. Although only 7% of school-age children in Santa Cruz were seronegative, the effectiveness of a mass campaign in this age group depends in part on the response to revaccination of children with low, but detectable, antibody levels.

Adolescent↗
PubMedDate not supplied

Maternal rubella-specific antibody prevalence in Ethiopian infants.

In countries with a high transmission rate of rubella the optimal age for universal rubella vaccination of infants is critically dependent upon the rate of loss of maternal antibodies. Few studies have investigated the decay characteristics of such antibodies. Mother:infant pairs were recruited at the Ethio-Swedish Children's Hospital, Addis Ababa, in 1994/95. Rubella antibody levels, determined by radial haemolysis, were available for analysis from 1542 infants aged 0-12 months, with 942 repeat measures, and from 846 mothers. Decay in seropositivity was well described by a delayed exponential function. The proportion seropositive at age 6, 9, or 12 months was 6-13%, 1-4%, or 0-1%, respectively, dependent upon assay cutoff level. Only infant age and mother's antibody level were important predictors of seropositivity. Results suggest that the success of vaccination at age 9 months or above would be little affected by residual maternal antibodies.

Adult↗
PubMedDate not supplied

Response to measles revaccination among Bolivian school-aged children.

The response to measles revaccination was evaluated in 1994 among 202 Bolivian school-aged children whose antibody levels were below 200 miu (milli-international units) by haemagglutination inhibition (HI) in a large-scale serosurvey conducted in Santa Cruz one year earlier. Of the 202 revaccinated children, 164 (82%) had seroconverted between the 1993 serosurvey and the pre-revaccination blood sample. A measles outbreak occurred in Santa Cruz 6 months before the revaccination. Among the seroconvertors, only 6% gave a history of measles, and 15% a history of contact with a case of measles. All 20 children with undetectable HI antibody pre-revaccination, and all 6 children with levels below 100 miu, seroconverted after revaccination. The geometric mean titres by HI at 4 weeks after revaccination were 2018 miu (95% confidence limits [95% CL] 1143, 3564) and 398 miu (95% CL 254, 625) in the 2 groups, respectively. Six of 9 children with pre-revaccination antibody titres of 100-199 miu also seroconverted. No child demonstrated a measles-specific immunoglobulin M response. Among the 29 children who seroconverted and were followed up at one year after revaccination, 15(52%) showed a fourfold or greater decline in antibody levels, which in 8 fell to levels below 200 miu. This study confirmed the observation that revaccination is successful in producing an antibody response in children with low or undetectable pre-revaccination titres, but it also confirmed that vaccine-induced immunity wanes rapidly.

Adolescent↗
PubMedDate not supplied

An evaluation of oral-fluid collection devices for the determination of rubella antibody status in a rural Ethiopian community.

We compared 3 different oral-fluid collection devices to assess their suitability for use in community studies of rubella antibody. Of 58 individuals enrolled from 13 households from a southern Ethiopian village, 38 provided a blood sample and oral fluids by the 3 devices: 2 proprietary, Omni-SAL and OraSure, and a third a polystyrene sponge swab (Sponge). The Sponge swab, used like a toothbrush, was most acceptable to survey staff and to participants of all ages, although it proved ill-adapted for fluid extraction. The other devices more often caused participant discomfort or anxiety, particularly in the young. Statistical comparison of rubella-specific immunoglobulin (Ig) G in oral fluid, measured by antibody-capture radioimmunoassay, and in serum, by indirect enzyme-linked immunosorbent assay, showed no clear differences between the devices in oral-fluid performance. Specificity range was 75-100% and sensitivity 73-85%, relative to serum. Specific-antibody levels declined with increasing age, with concomitant decreases in sensitivity, as previously documented. The relationship between specific IgG and total IgG in oral fluid differed by device. Specific IgG levels were highly correlated between paired samples using the Sponge device. We consider the Sponge device to be the most suitable for community survey work, although the extraction method requires improvement. Further work is needed to improve the sensitivity of antibody status determination in adults.

Adolescent↗
PubMedDate not supplied

Efficacy of nine-valent pneumococcal conjugate vaccine against pneumonia and invasive pneumococcal disease in The Gambia: randomised, double-blind, placebo-controlled trial.

BACKGROUND: Pneumonia is estimated to cause 2 million deaths every year in children. Streptococcus pneumoniae is the most important cause of severe pneumonia. We aimed to assess the efficacy of a nine-valent pneumococcal conjugate vaccine in children. METHODS: We undertook a randomised, placebo-controlled, double-blind trial in eastern Gambia. Children age 6-51 weeks were randomly allocated three doses of either pneumococcal conjugate vaccine (n=8718) or placebo (8719), with intervals of at least 25 days between doses. Our primary outcome was first episode of radiological pneumonia. Secondary endpoints were clinical or severe clinical pneumonia, invasive pneumococcal disease, and all-cause admissions. Analyses were per protocol and intention to treat. FINDINGS: 529 children assigned vaccine and 568 allocated placebo were not included in the per-protocol analysis. Results of per-protocol and intention-to-treat analyses were similar. By per-protocol analysis, 333 of 8189 children given vaccine had an episode of radiological pneumonia compared with 513 of 8151 who received placebo. Pneumococcal vaccine efficacy was 37% (95% CI 27-45) against first episode of radiological pneumonia. First episodes of clinical pneumonia were reduced overall by 7% (95% CI 1-12). Efficacy of the conjugate vaccine was 77% (51-90) against invasive pneumococcal disease caused by vaccine serotypes, 50% (21-69) against disease caused by all serotypes, and 15% (7-21) against all-cause admissions. We also found an efficacy of 16% (3-28) against mortality. 110 serious adverse events arose in children given the pneumococcal vaccine compared with 131 in those who received placebo. INTERPRETATION: In this rural African setting, pneumococcal conjugate vaccine has high efficacy against radiological pneumonia and invasive pneumococcal disease, and can substantially reduce admissions and improve child survival. Pneumococcal conjugate vaccines should be made available to African infants.

Child, Preschool↗
PubMedDate not supplied

[Measles control in developing countries].

The EPI has made significant progress in reducing global morbidity and mortality from measles. Many countries are considering the need for additional strategies in response to the changes in measles epidemiology which occur when vaccination coverage increases. Measles vaccination changes the relative age distribution of cases towards older groups, because measles transmission becomes less intense so that children reach older ages before being exposed to wild virus. The proportion of cases occurring below the target age group for vaccination may also increase, though the number of cases does not always increase. Outbreaks are likely to occur after some years of low incidence in countries which have moderate or high coverage, for several reasons. Firstly, susceptibles gradually accumulate over a number of years until a "post-honeymoon" outbreak occurs. Second, there may be pockets of low coverage which occur for example in urban slums, in nomadic and other inaccessible populations, or among groups with religious or philosophical objections to vaccination. Third, outbreaks can occur among vaccinated children who did not respond to the vaccine. Even in industrialized countries, where measles vaccine is administered in the second year of life and is over 90% effective in protecting against disease, small outbreaks have occurred among vaccine failures under conditions of close contact such as school settings. In developing countries, where measles vaccine is usually administered at age 9 months, approximately 15% of children are not protected, and vaccine failures can be expected to play an increasing role in outbreaks in the future. Furthermore, if vaccine efficacy is reduced because of poor vaccine storage or handling, large outbreaks may occur.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗