Integrating Blood Collection Within Household Surveys: Lessons Learned From Nesting a Measles and Rubella Serological Survey Within a Post-Campaign Coverage Evaluation Survey in Southern Province, Zambia

Age-specific population immunity to many vaccine-preventable diseases can be measured using serological surveys. However, stand-alone serological surveys are infrequently conducted in low- and middle-income countries because of costs, operational challenges, and potential high refusal rates for blood collection. Nesting a serosurvey within a household cluster survey may overcome some of these challenges. We share lessons learned from nesting a serosurvey within a measles and rubella vaccination post-campaign coverage evaluation survey (PCES). In 15 of the 26 PCES clusters in Southern Province, Zambia, we collected dried blood spots from 581 participants aged 9 months and older. Household participation rates for the main PCES were higher in the serosurvey clusters (86%) than PCES-only clusters (71%), suggesting that a serosurvey can be successfully integrated without adversely affecting PCES participation. Among households that participated in the PCES, 80% also participated in the serosurvey and 86% of individuals available in the household provided a blood sample for the serosurvey. Substantial planning and coordination, additional staff training, and community mobilization were critical to the success of the serosurvey. Most challenges stemmed from using different data collecting tools and teams for the serosurvey and PCES. A more efficient design would be to fully integrate the serosurvey by adding blood collection and additional questions to the PCES

Effect of cotrimoxazole on causes of death, hospital admissions and antibiotic use in HIV-infected children.

BACKGROUND: Cotrimoxazole prophylaxis reduces morbidity and mortality in HIV-1-infected children, but mechanisms for these benefits are unclear. METHODS: CHAP was a randomized trial comparing cotrimoxazole prophylaxis with placebo in HIV-infected children in Zambia where background bacterial resistance to cotrimoxazole is high. We compared causes of mortality and hospital admissions, and antibiotic use between randomized groups. RESULTS: Of 534 children (median age, 4.4 years; 32% 1-2 years), 186 died and 166 had one or more hospital admissions not ending in death. Cotrimoxazole prophylaxis was associated with lower mortality, both outside hospital (P = 0.01) and following hospital admission (P = 0.005). The largest excess of hospital deaths in the placebo group was from respiratory infections [22/56 (39%) placebo versus 10/35 (29%) cotrimoxazole]. By 2 years, the cumulative probability of dying in hospital from a serious bacterial infection (predominantly pneumonia) was 7% on cotrimoxazole and 12% on placebo (P = 0.08). There was a trend towards lower admission rates for serious bacterial infections in the cotrimoxazole group (19.1 per 100 child-years at risk versus 28.5 in the placebo group, P = 0.09). Despite less total follow-up due to higher mortality, more antibiotics (particularly penicillin) were prescribed in the placebo group in year one [6083 compared to 4972 days in the cotrimoxazole group (P = 0.05)]. CONCLUSIONS: Cotrimoxazole prophylaxis appears to mainly reduce death and hospital admissions from respiratory infections, supported further by lower rates of antibiotic prescribing. As such infections occur at high CD4 cell counts and are common in Africa, the role of continuing cotrimoxazole prophylaxis after starting antiretroviral therapy requires investigation

Measles and Rubella Serosurvey Identifies Rubella Immunity Gap in Young Adults of Childbearing Age in Zambia: The Added Value of Nesting a Serological Survey Within a Post-Campaign Coverage Evaluation Survey

Background: Serological surveys can potentially complement vaccine coverage surveys, such as post-vaccination campaign coverage evaluation surveys (PCES), by providing direct information on population immunity within and outside the target age range of the mass vaccination campaign. We estimate age-specific population immunity to measles and rubella viruses in Southern Province, Zambia, and assess the value of adding serological data to vaccination coverage estimates by nesting a serological survey within a PCES. Methods: Dried blood spots (DBS) from fingerprick blood were collected from all individuals ages nine months or older in households participating in the PCES and tested for measles and rubella virus-specific immunoglobulin G (IgG) by enzyme immunoassay (Siemens Enzygnost, Marburg, Germany). Results: Overall seroprevalence was 95.5% (95% CI: 92.8, 97.2) for measles virus-specific IgG and 97.7% (95% CI: 96.0, 98.7) for rubella virus-specific IgG. Rubella seroprevalence was 98.4% (95% CI: 95.9, 99.4) among children eligible for the MR vaccination campaign, significantly higher than the reported measles-rubella (MR) vaccination campaign coverage of 89.8% (p = 0.003), and higher than the 91.3% rubella seroprevalence for adolescents and adults 16–30 years of age (p = 0.049). Conclusion: Seroprevalence to measles and rubella viruses in children younger than 16 years of age was significantly higher than expected from vaccination coverage estimates, likely reflecting exposure to wild-type viruses and underreporting of vaccination. The serosurvey revealed rubella immunity gaps among women 16–30 years of age, precisely the age group in which protection from rubella is most important to prevent congenital rubella syndrome. Nesting serological surveys within existing surveys can leverage resources and infrastructure while providing complementary information important to immunization programs. © 2019 The Author(s

Análise genética de escores de avaliação visual de bovinos com modelos bayesianos de limiar e linear Genetic analysis for visual scores of bovines with the linear and threshold bayesian models

O objetivo deste trabalho foi comparar as estimativas de parâmetros genéticos obtidas em análises bayesianas uni-característica e bi-característica, em modelo animal linear e de limiar, considerando-se as características categóricas morfológicas de bovinos da raça Nelore. Os dados de musculosidade, estrutura física e conformação foram obtidos entre 2000 e 2005, em 3.864 animais de 13 fazendas participantes do Programa Nelore Brasil. Foram realizadas análises bayesianas uni e bi-características, em modelos de limiar e linear. De modo geral, os modelos de limiar e linear foram eficientes na estimação dos parâmetros genéticos para escores visuais em análises bayesianas uni-características. Nas análises bi-características, observou-se que: com utilização de dados contínuos e categóricos, o modelo de limiar proporcionou estimativas de correlação genética de maior magnitude do que aquelas do modelo linear; e com o uso de dados categóricos, as estimativas de herdabilidade foram semelhantes. A vantagem do modelo linear foi o menor tempo gasto no processamento das análises. Na avaliação genética de animais para escores visuais, o uso do modelo de limiar ou linear não influenciou a classificação dos animais, quanto aos valores genéticos preditos, o que indica que ambos os modelos podem ser utilizados em programas de melhoramento genético.<br>The objective of this work was to compare the estimates of genetic parameters obtained in single-trait and two-trait bayesian analyses, under linear and threshold animal models, considering categorical morphological traits of bovines of the Nelore breed. Data of musculature, physical structure and conformation were obtained between years 2000 and 2005, from 3,864 bovines of the Nelore breed from 13 participant farms of the Nelore Brazil Program. Single-trait and two-trait bayesian analyses were performed under linear and threshold animal models. In general, the linear and threshold models were efficient in estimating genetic parameters for visual scores under single-trait bayesian analyses. In the two-trait analyses, it was observed that: using continuous and categorical data, the threshold model provided greater estimates of genetic correlation than those of the linear model; with categorical data, the heritability estimates were similar. One major advantage of the linear models was its smaller requirements in the analyses processing time. In the genetic evaluation of animals for visual scores, the use of the linear or threshold model did not influence the classification of the animals, based on their predicted breeding values, which suggests that both models can be used in genetic improvement programs