Michael S. Deming

Increasing the accuracy of the Expanded Programme on Immunization's cluster survey design.

The Expanded Programme on Immunization (EPI) of the World Health Organization developed a cluster survey design for the rapid assessment of childrens vaccination coverage in developing countries. Because of its simplicity and familiarity, the EPI methodology has been used for additional purposes, including the detection of relatively small changes in vaccination coverage levels that are already high and the estimation of other population parameters when moderate accuracy is required. This article suggests techniques for improving the accuracy of the EPI cluster survey method, including (a) segmenting sample clusters, if necessary, so that reasonably sized areas can be counted, mapped, and listed; (b) selecting an equal probability sample of housing units within a cluster; (c) selecting a fixed number of housing units per sample cluster; and (d) performing weighted analyses. These procedures will produce accurate estimators and corresponding standard errors in EPI cluster surveys.

Transmission assessment surveys (TAS) to define endpoints for lymphatic filariasis mass drug administration: a multicenter evaluation.

Background Lymphatic filariasis (LF) is targeted for global elimination through treatment of entire at-risk populations with repeated annual mass drug administration (MDA). Essential for program success is defining and confirming the appropriate endpoint for MDA when transmission is presumed to have reached a level low enough that it cannot be sustained even in the absence of drug intervention. Guidelines advanced by WHO call for a transmission assessment survey (TAS) to determine if MDA can be stopped within an LF evaluation unit (EU) after at least five effective rounds of annual treatment. To test the value and practicality of these guidelines, a multicenter operational research trial was undertaken in 11 countries covering various geographic and epidemiological settings. Methodology The TAS was conducted twice in each EU with TAS-1 and TAS-2 approximately 24 months apart. Lot quality assurance sampling (LQAS) formed the basis of the TAS survey design but specific EU characteristics defined the survey site (school or community), eligible population (6–7 year olds or 1st–2nd graders), survey type (systematic or cluster-sampling), target sample size, and critical cutoff (a statistically powered threshold below which transmission is expected to be no longer sustainable). The primary diagnostic tools were the immunochromatographic (ICT) test for W. bancrofti EUs and the BmR1 test (Brugia Rapid or PanLF) for Brugia spp. EUs. Principal Findings/Conclusions In 10 of 11 EUs, the number of TAS-1 positive cases was below the critical cutoff, indicating that MDA could be stopped. The same results were found in the follow-up TAS-2, therefore, confirming the previous decision outcome. Sample sizes were highly sex and age-representative and closely matched the target value after factoring in estimates of non-participation. The TAS was determined to be a practical and effective evaluation tool for stopping MDA although its validity for longer-term post-MDA surveillance requires further investigation.

Health worker perceptions of how being observed influences their practices during consultations with ill children

The abscess cavity size was determined by ultrasonography. Abscesses more than 60 mL capacity were observed in 24%, 20% and 12% of patients in groups A, Band C, respectively. Staphylococcus aureus was the only organism isolated in 80% of the specimens and was uniformly sensitive to cefazolin. No growth was observed in the other specimens. Transient bacteraemia was seen in three patients of group C only in whom S. aureus could be isolated in the blood culture. The drain was irrigated if it became blocked but led to secondary infection in 20%, 12%, and 4% patients in groups A, Band C, respectively. Wound infection in the form of frank purulent discharge was observed in 16%, 12% and 24% of patients in groups A, Band C, respectively. Such wounds were laid open and allowed to heal by secondary intention. Excluding cases with infection, healing was achieved in an average of 7.3, 6.9 and 7.4 days in the three groups, respectively. The recurrence rates observed were almost similar 8%, 12% and 10% in group A, Band C, respectively.

Comparison of methods for estimating drug coverage for filariasis elimination, Leogane Commune, Haiti

In the global effort to eliminate lymphatic filariasis, annual mass treatments are conducted with diethylcarbamazine (DEC) or ivermectin, combined with albendazole. The success of this strategy depends on achieving high levels of drug coverage, which reduces the number of persons with circulating microfilariae so that transmission of the parasite is interrupted. Because resources are often limited, a simple, inexpensive, and reliable method to estimate drug coverage is needed. During the period December 2000 to February 2001, three methods were used to assess drug coverage in Leogane Commune, Haiti: a probability survey using a cluster sample design (n = 1421 persons); a distribution-point survey based on a convenience sample of houses near the distribution points (n = 4341 persons); and a survey based on a convenience sample of primary schools (n = 5036 children). The coverage estimations were 71.3% (95% CI 66.7-75.9), 73.6% (95% CI 70.1-77.0), and 77.8% (95% CI 73.5-82.1), respectively. Survey costs for the probability, distribution point, and school surveys were US

Tetanus toxoid coverage as an indicator of serological protection against neonatal tetanus

2217, US

Campylobacter jejuni infections on college campuses: a national survey.

979, and US

Longitudinal analysis of community health workers’ adherence to treatment guidelines, Siaya, Kenya, 1997–2002

312, respectively. The 2 convenience sampling methods provided point estimates of drug coverage that were similar to those of the probability survey. These methods may have a role for monitoring drug treatment coverage between less frequent, but more costly, probability sample surveys.

Antimicrobial resistance of nasopharyngeal isolates of Streptococcus pneumoniae and Haemophilus influenzae from children in the Central African Republic.

OBJECTIVE A Multiple-Indicator Cluster Survey (MICS) was conducted at mid-decade in more than 60 developing countries to measure progress towards the year 2000 World Summit for Children goals. These goals included the protection of at least 90% of children against neonatal tetanus through the immunization of their mothers, as measured by tetanus toxoid (TT) coverage. In the Central African Republic (CAR), serological testing was added to the MICS to understand better the relationship between survey estimates of TT coverage and the prevalence of serological protection. METHODS In the CAR MICS, mothers of children younger than one year of age gave verbal histories of the TT vaccinations they had received, using the MICS TT questionnaire. A subsample of mothers was tested for tetanus antitoxin, using a double-antigen enzyme-linked immunoadsorbent assay (ELISA). Seropositivity was defined as a titre of > or =0.01 IU/ml, and TT coverage was defined as the proportion of mothers protected at delivery, according to their history of TT vaccinations. FINDINGS Among the 222 mothers in the subsample, weighted TT coverage was 74.4% (95% Confidence Interval (CI); 67.0% - 81.7%) and tetanus antitoxin seroprevalence was 88.7% (95% CI; 83.2% - 94.2%). The weighted median antitoxin titre was 0.35 IU/ml. CONCLUSIONS Tetanus toxoid coverage in the CAR was lower than the prevalence of serological protection against neonatal tetanus. If this relationship holds for other countries, TT coverage estimates from the MICS may underestimate the extent to which the year 2000 goal for protecting children against neonatal tetanus was reached. We also showed that a high level of serological protection had been achieved in a country facing major public health challenges and resource constraints.

Evaluating health worker performance in Benin using the simulated client method with real children

We surveyed 303 colleges and universities to determine the frequency of isolations of Campylobacter jejuni and other enteric bacterial pathogens. Campylobacter cultures could be obtained at 74 per cent; 10 per cent of stool cultures yielded Campylobacter, which was isolated 10 and 46 times more frequently than Salmonella and Shigella, respectively. The incidence of diagnosed Campylobacter infections was 1.3 per 10,000 enrolled students per month. Intercollegiate variation was not explained by differences in gender composition, the proportion of students living off-campus, or geographic characteristics of the campus.

Impact of a Malaria-Control Project in Benin That Included the Integrated Management of Childhood Illness Strategy

Objectives  To investigate community health workers’ (CHW) adherence over time to guidelines for treating ill children and to assess the effect of refresher training on adherence.