Background malaria incidence and parasitemia during the three-dose RTS,S/AS01 vaccination series do not reduce magnitude of antibody response nor efficacy against the first case of malaria.

BACKGROUND: RTS,S/AS01 has been recommended by WHO for widespread implementation in medium to high malaria transmission settings. Previous analyses have noted lower vaccine efficacies in higher transmission settings, possibly due to the more rapid development of naturally acquired immunity in the control group. METHODS: To investigate a reduced immune response to vaccination as a potential mechanism behind lower efficacy in high transmission areas, we examine initial vaccine antibody (anti-CSP IgG) response and vaccine efficacy against the first case of malaria (to exclude the effect of naturally acquired immunity) using data from three study areas (Kintampo, Ghana; Lilongwe, Malawi; Lambaréné, Gabon) from the 2009-2014 phase III trial (NCT00866619). Our key exposures are parasitemia during the vaccination series and background malaria incidence. We calculate vaccine efficacy (one minus hazard ratio) using a cox-proportional hazards model and allowing for the time-varying effect of RTS,S/AS01. RESULTS: We find that antibody responses to the primary three-dose vaccination series were higher in Ghana than in Malawi and Gabon, but that neither antibody levels nor vaccine efficacy against the first case of malaria varied by background incidence or parasitemia during the primary vaccination series. CONCLUSIONS: We find that vaccine efficacy is unrelated to infections during vaccination. Contributing to a conflicting literature, our results suggest that vaccine efficacy is also unrelated to infections before vaccination, meaning that control-group immunity is likely a major reason for lower efficacy in high transmission settings, not reduced immune responses to RTS,S/AS01. This may be reassuring for implementation in high transmission settings, though further studies are needed.

Malaria Transmission Intensity and Parasitemia during the Three-Dose RTS,S/AS01 Vaccination Series do not Reduce Magnitude of Antibody Response nor Efficacy Against the First Case of Malaria.

Background: RTS,S/AS01 has been recommended by WHO for widespread implementation in medium to high malaria transmission settings. Previous analyses have noted lower vaccine efficacies in higher transmission settings, possibly due to the more rapid development of naturally acquired immunity in the control group. Methods: To investigate a reduced immune response to vaccination as a potential mechanism behind lower efficacy in high transmission areas, we examine initial vaccine antibody (anti-CSP IgG) response and vaccine efficacy against the first case of malaria to exclude the delayed malaria effect using data from three study areas (Kintampo, Ghana; Lilongwe, Malawi; Lambaréné, Gabon) from the 2009-2014 phase III trial (NCT00866619). Our key exposures are parasitemia during the vaccination series and malaria transmission intensity. We calculate vaccine efficacy (one minus hazard ratio) using a cox-proportional hazards model and allowing for the time-varying effect of RTS,S/AS01. Results: We find that antibody responses to the primary three-dose vaccination series were higher in Ghana than in Malawi and Gabon, but that neither antibody levels nor vaccine efficacy against the first case of malaria varied by transmission intensity or parasitemia during the primary vaccination series. Conclusions: We find that vaccine efficacy is unrelated to infections during vaccination. Contributing to a conflicting literature, our results suggest that vaccine efficacy is also unrelated to infections before vaccination, meaning that delayed malaria is likely the main reason for lower efficacy in high transmission settings, not reduced immune responses. This may be reassuring for implementation in high transmission settings, though further studies are needed.

Malaria Transmission Intensity Likely Modifies RTS, S/AS01 Efficacy Due to a Rebound Effect in Ghana, Malawi, and Gabon.

BACKGROUND: RTS,S/AS01 is the first malaria vaccine to be approved and recommended for widespread implementation by the World Health Organization (WHO). Trials reported lower vaccine efficacies in higher-incidence sites, potentially due to a "rebound" in malaria cases in vaccinated children. When naturally acquired protection in the control group rises and vaccine protection in the vaccinated wanes concurrently, malaria incidence can become greater in the vaccinated than in the control group, resulting in negative vaccine efficacies. METHODS: Using data from the 2009-2014 phase III trial (NCT00866619) in Lilongwe, Malawi; Kintampo, Ghana; and Lambaréné, Gabon, we evaluate this hypothesis by estimating malaria incidence in each vaccine group over time and in varying transmission settings. After estimating transmission intensities using ecological variables, we fit models with 3-way interactions between vaccination, time, and transmission intensity. RESULTS: Over time, incidence decreased in the control group and increased in the vaccine group. Three-dose efficacy in the lowest-transmission-intensity group (0.25 cases per person-year [CPPY]) decreased from 88.2% to 15.0% over 4.5 years, compared with 81.6% to -27.7% in the highest-transmission-intensity group (3 CPPY). CONCLUSIONS: These findings suggest that interventions, including the fourth RTS,S dose, that protect vaccinated individuals during the potential rebound period should be implemented for high-transmission settings.

Profile and predictors of adolescent tobacco use in Ghana: evidence from the 2017 Global Youth Tobacco Survey (GYTS).

BACKGROUND: Understanding the predictive factors for tobacco use, and initiation among the youth is critical for effective intervention and prevention. We, therefore, aimed to determine the profile, associated factors, the regional disparities in the use of tobacco products among the youth in Ghana. METHOD: The study used the 2017 Ghana Global Youth Tobacco Survey (GYTS) to obtain tobacco-related information among the youth in Junior High Schools across the country. The survey used a two-stage cluster randomized sampling technique to obtain nationally representative data. Weighted univariate and multivariate logistic regression analyses were used to assess the association of participant's characteristics and use of tobacco. RESULTS: Out of the 6039 targeted respondents, 5,664 (93.8%) participated, 2,707 males, 2,929 females, and 28 of the participants had missing gender data. The use of any tobacco product (cigarette, smokeless tobacco, electronic cigarette, or waterpipe tobacco) was 28.3, 7.0, and 4.8% in the Savanna/northern zone, middle/forest zone, and Coastal zone respectively. From the univariate analysis, age (p = 0.005), pocket money (p < 0.001), and exposure to secondhand smoke (SHS) at home (p < 0.001) were significantly associated with tobacco use. In the multivariate analysis, age (p = 0.002), pocket money (p < 0.001), exposure to SHS at home (p < 0.001), and being taught about the dangers of tobacco use (p = 0.043) were significantly associated with tobacco use. CONCLUSION: Multiple factors including age, pocket money, exposure to SHS were identified to be associated with tobacco use among the youth in Ghana. Promoting anti-smoking campaigns in early adolescence, as well as programmes targeting early tobacco use can guard the youth against initiating tobacco use.

Open defecation and attainment of Sustainable Development Goal Six: evidence from Kintampo Surveillance System, Ghana.

Objective: This study examined whether the open-defecation (OD) free target is achievable by 2030. Design: Longitudinal study. Setting: Seven sub-Districts of Kintampo North Municipal, and five sub-Districts of Kintampo South District. Data source: Kintampo health and demographic surveillance system. Participants: Data was collected from household heads or their representatives over a 12-year period from 2005 to 2016. Main outcome: Open-defecation and attainment of OD free by 2030. Results: In an exploratory analysis, the correlation between the total number of households, year, and total number of OD households was obtained. The average percentage yearly increase or decrease in OD was computed and used to project the percentage of OD for the years 2020, 2025 and 2030. In addition, geo-spatial technology was used to visualize variability in OD across the twelve sub-Districts. The results showed that the OD free target is not achievable in 2030 or even if the current trend continues. In 2016, 44.2 per cent of the 31,571 households defecated openly. In six out of the 12 sub-Districts, more than half of the households openly defecated. Four out of these six sub-Districts were in the Kintampo North Municipality. Conclusion: The 2030 OD free target is not achievable in the Kintampo districts of Ghana if the current trend continues. Funding: Kintampo Health Research Centre funded this work.

The Influence of Apparent Temperature on Mortality in the Kintampo Health and Demographic Surveillance Area in the Middle Belt of Ghana: A Retrospective Time-Series Analysis.

Globally, studies have shown that diurnal changes in weather conditions and extreme weather events have a profound effect on mortality. Here, we assessed the effect of apparent temperature on all-cause mortality and the modifying effect of sex on the apparent temperature-mortality relationship using mortality and weather data archived over an eleven-year period. An overdispersed Poisson regression and distributed lag nonlinear models were used for this analysis. With these models, we analysed the relative risk of mortality at different temperature values over a 10-day lag period. By and large, we observed a nonlinear association between mean daily apparent temperature and all-cause mortality. An assessment of different temperature values over a 10-day lag period showed an increased risk of death at the lowest apparent temperature (18°C) from lag 2 to 4 with the highest relative risk of mortality (RR = 1.61, 95% CI: 1.2, 2.15, p value = 0.001) occurring three days after exposure. The relative risk of death also varied between males (RR = 0.31, 95% CI: 0.10, 0.94) and females (RR = 4.88, 95% CI: 1.40, 16.99) by apparent temperature and lag. On the whole, males are sensitive to both temperature extremes whilst females are more vulnerable to low temperature-related mortality. Accordingly, our findings could inform efforts at reducing temperature-related mortality in this context and other settings with similar environmental and demographic characteristics.

Utilization of community-based health planning and services compounds in the Kintampo North Municipality: a cross-sectional descriptive correlational study.

BACKGROUND: The Community-based Health Planning and Services (CHPS) initiative was introduced to improve coverage and utilization of basic health services for people in remote rural communities whose use of orthodox health services was hitherto limited by distance. To achieve this aim, the scheme has so far been scaled up to several communities nationwide as part of government's agenda to improve the general wellbeing of the populace. The objectives of this study were to examine the extent of patronage of CHPS compounds in the Kintampo North Municipality, factors associated with their use and challenges faced by community members regarding the use of these facilities. METHODS: We adopted a descriptive cross-sectional correlational design for this study. We collected data from 171 household heads or their representatives, selected through a multistage sampling technique. The respondents were drawn from five randomly selected communities among those with CHPS compounds and their proportions weighted based on the populations of these communities. RESULTS: Our analysis revealed that a high proportion (73.7%) of the respondents patronized CHPS compounds for health care. We also found sex and income to predict the use of the facilities though income was less significant after adjusting for sex in a multivariate analysis. Females were about six times more likely than males to patronize CHPS compounds (adjusted OR = 5.98, 95% CI 2.55, 14.0, P = < 0.01). Household heads earning between GH¢ 200.00 and GH¢ 300.00 were about nine times more likely to use the facilities than those who earned below GH¢ 100.00 (adjusted OR = 8.88, 95% CI 1.94, 40.6, P = 0.05). Our findings also showed that shortage of medicines (41.5%), lack of money to pay for services (28.7%) and absenteeism of Community Health Officers (CHOs) (12.3%) were major barriers to the use of the facilities. CONCLUSIONS: Based on the foregoing findings, there is an apparent need to ensure timely replenishment of medicines at the facilities and step up supervision of CHOs in order to sustain patronage of the compounds.

Methods to measure potential spatial access to delivery care in low- and middle-income countries: a case study in rural Ghana.

BACKGROUND: Access to skilled attendance at childbirth is crucial to reduce maternal and newborn mortality. Several different measures of geographic access are used concurrently in public health research, with the assumption that sophisticated methods are generally better. Most of the evidence for this assumption comes from methodological comparisons in high-income countries. We compare different measures of travel impedance in a case study in Ghana's Brong Ahafo region to determine if straight-line distance can be an adequate proxy for access to delivery care in certain low- and middle-income country (LMIC) settings. METHODS: We created a geospatial database, mapping population location in both compounds and village centroids, service locations for all health facilities offering delivery care, land-cover and a detailed road network. Six different measures were used to calculate travel impedance to health facilities (straight-line distance, network distance, network travel time and raster travel time, the latter two both mechanized and non-mechanized). The measures were compared using Spearman rank correlation coefficients, absolute differences, and the percentage of the same facilities identified as closest. We used logistic regression with robust standard errors to model the association of the different measures with health facility use for delivery in 9,306 births. RESULTS: Non-mechanized measures were highly correlated with each other, and identified the same facilities as closest for approximately 80% of villages. Measures calculated from compounds identified the same closest facility as measures from village centroids for over 85% of births. For 90% of births, the aggregation error from using village centroids instead of compound locations was less than 35 minutes and less than 1.12 km. All non-mechanized measures showed an inverse association with facility use of similar magnitude, an approximately 67% reduction in odds of facility delivery per standard deviation increase in each measure (OR = 0.33). CONCLUSION: Different data models and population locations produced comparable results in our case study, thus demonstrating that straight-line distance can be reasonably used as a proxy for potential spatial access in certain LMIC settings. The cost of obtaining individually geocoded population location and sophisticated measures of travel impedance should be weighed against the gain in accuracy.