Longitudinal estimation of Plasmodium falciparum prevalence in relation to malaria prevention measures in six sub-Saharan African countries.

BACKGROUND: Plasmodium falciparum prevalence (PfPR) is a widely used metric for assessing malaria transmission intensity. This study was carried out concurrently with the RTS,S/AS01 candidate malaria vaccine Phase III trial and estimated PfPR over ≤ 4 standardized cross-sectional surveys. METHODS: This epidemiology study (NCT01190202) was conducted in 8 sites from 6 countries (Burkina Faso, Gabon, Ghana, Kenya, Malawi, and Tanzania), between March 2011 and December 2013. Participants were enrolled in a 2:1:1 ratio according to age category: 6 months-4 years, 5-19 years, and ≥ 20 years, respectively, per year and per centre. All sites carried out surveys 1-3 while survey 4 was conducted only in 3 sites. Surveys were usually performed during the peak malaria parasite transmission season, in one home visit, when medical history and malaria risk factors/prevention measures were collected, and a blood sample taken for rapid diagnostic test, microscopy, and haemoglobin measurement. PfPR was estimated by site and age category. RESULTS: Overall, 6401 (survey 1), 6411 (survey 2), 6400 (survey 3), and 2399 (survey 4) individuals were included in the analyses. In the 6 months-4 years age group, the lowest prevalence (assessed using microscopy) was observed in 2 Tanzanian centres (4.6% for Korogwe and 9.95% for Bagamoyo) and Lambaréné, Gabon (6.0%), while the highest PfPR was recorded for Nanoro, Burkina Faso (52.5%). PfPR significantly decreased over the 3 years in Agogo (Ghana), Kombewa (Kenya), Lilongwe (Malawi), and Bagamoyo (Tanzania), and a trend for increased PfPR was observed over the 4 surveys for Kintampo, Ghana. Over the 4 surveys, for all sites, PfPR was predominantly higher in the 5-19 years group than in the other age categories. Occurrence of fever and anaemia was associated with high P. falciparum parasitaemia. Univariate analyses showed a significant association of anti-malarial treatment in 4 surveys (odds ratios [ORs]: 0.52, 0.52, 0.68, 0.41) and bed net use in 2 surveys (ORs: 0.63, 0.68, 1.03, 1.78) with lower risk of malaria infection. CONCLUSION: Local PfPR differed substantially between sites and age groups. In children 6 months-4 years old, a significant decrease in prevalence over the 3 years was observed in 4 out of the 8 study sites. Trial registration Clinical Trials.gov identifier: NCT01190202:NCT. GSK Study ID numbers: 114001

National stakeholder preferences for next-generation rotavirus vaccines: Results from a six-country study

Background: Currently available live, oral rotavirus vaccines (LORVs) have significantly reduced severe rotavirus hospitalizations and deaths worldwide. However, LORVs are not as effective in low- and middle-income countries (LMIC) where rotavirus disease burden is highest. Next-generation rotavirus vaccine (NGRV) candidates in development may have a greater public health impact where they are needed most. The feasibility and acceptability of possible new rotavirus vaccines were explored as part of a larger public health value proposition for injectable NGRVs in LMICs. Objective: To assess national stakeholder preferences for currently available LORVs and hypothetical NGRVs and understand rationales and drivers for stated preferences. Methods: Interviews were conducted with 71 national stakeholders who influence vaccine policy and national programming. Stakeholders from Ghana, Kenya, Malawi, Peru, Senegal, and Sri Lanka were interviewed using a mixed-method guide. Vaccine preferences were elicited on seven vaccine comparisons involving LORVs and hypothetical NGRVs based on information presented comparing the vaccines’ attributes. Reasons for vaccine preference were elicited in open-ended questions, and the qualitative data were analyzed on key preference drivers. Results: Nearly half of the national stakeholders interviewed preferred a highly effective standalone, injectable NGRV over current LORVs. When presented as having similar efficacy to the LORV, however, very few stakeholders preferred the injectable NGRV, even at substantially lower cost. Similarly, a highly effective standalone injectable NGRV was generally not favored over an equally effective oral NGRV following a neonatal-infant schedule, despite higher cost of the neonatal option. An NGRV-DTP-containing combination vaccine was strongly preferred over all other options, whether delivered alone with efficacy similar to current LORVs or co-administered alongside an LORV (LORV + NGRV-DTP) to increase efficacy. Conclusion: Results from these national stakeholder interviews provide valuable insights to inform ongoing and future NGRV research and development.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Healthcare provider perspectives on delivering next generation rotavirus vaccines in five low-to-middle-income countries

Background Live oral rotavirus vaccines (LORVs) have significantly reduced rotavirus hospitalizations and deaths worldwide. However, LORVs are less effective in low- and middle-income countries (LMICs). Next-generation rotavirus vaccines (NGRVs) may be more effective but require administration by injection or a neonatal oral dose, adding operational complexity. Healthcare providers (HPs) were interviewed to assess rotavirus vaccine preferences and identify delivery issues as part of an NGRV value proposition. Objective Determine HP vaccine preferences about delivering LORVs compared to injectable (iNGRV) and neonatal oral (oNGRV) NGRVs. Methods 64 HPs from Ghana, Kenya, Malawi, Peru, and Senegal were interviewed following a mixed-method guide centered on three vaccine comparisons: LORV vs. iNGRV; LORV vs. oNGRV; oNGRV vs. iNGRV. HPs reviewed attributes for each vaccine in the comparisons, then indicated and explained their preference. Additional questions elicited views about co-administering iNGRV+LORV for greater public health impact, a possible iNGRV-DTP-containing combination vaccine, and delivering neonatal doses. Results Almost all HPs preferred oral vaccine options over iNGRV, with many emphasizing an aversion to additional injections. Despite this strong preference, HPs described challenges delivering oral doses. Preferences for LORV vs. oNGRV were split, marked by disparate views on rotavirus disease epidemiology and the safety, need, and feasibility of delivering neonatal vaccines. Although overwhelmingly enthusiastic about an iNGRV-DTP-containing combination option, several HPs had concerns. HP views were divided on the feasibility of co-administering iNGRV+LORV, citing challenges around logistics and caregiver sensitization. Conclusion Our findings provide valuable insights on delivering NGRVs in routine immunization. Despite opposition to injectables, openness to co-administering LORV+iNGRV to improve efficacy suggests future HP support of iNGRV if adequately informed of its advantages. Rationales for LORV vs. oNGRV underscore needs for training on rotavirus epidemiology and stronger service integration. Expressed challenges delivering existing LORVs merit further examination and indicate need for improved delivery.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Exploring Shigella vaccine priorities and preferences: Results from a mixed-methods study in low- and middle-income settings

Background: Shigella is the leading bacterial cause of diarrheal mortality in children and can cause long-term effects on growth and development. No licensed Shigella vaccines currently exist but several promising candidates are in development and could be available in the next five years. Despite Shigella being a well-known public health target of the World Health Organization for decades, given current burden estimates and competing preventable disease priorities in low-income settings, whether the availability of an effective Shigella vaccine will lead to its prioritization and widespread introduction among countries at highest risk is unknown. Methods: We conducted a mixed-methods study of national stakeholders and healthcare providers in five countries in Asia and Africa and regional stakeholders in the Pan American Health Organization to identify preferences and priorities for forthcoming Shigella vaccines. Results: In our study of 89 individuals, diarrhea was the most frequently mentioned serious health concern for children under five years. Antimicrobial resistance (AMR) was more often considered very concerning than diarrhea or stunting. Shigella awareness was high but not considered a serious health concern by most stakeholders. Most participants were willing to consider adding a new vaccine to the routine immunization schedule but expressed reservations about a Shigella vaccine because of lower perceived burden relative to other preventable diseases and an already crowded schedule; interest was highest among national stakeholders in countries receiving more financial support for immunization. The priority of a Shigella vaccine rose when participants considered vaccine impacts on reducing stunting and AMR. Participants strongly preferred oral and combination vaccines compared to injectable and a single-antigen presentations, citing greater perceived community acceptability. Conclusions: This study provides a critical opportunity to hear directly from country and regional stakeholders about health priorities and preferences around new vaccines. These findings should inform ongoing Shigella vaccine development efforts and eventual vaccine introduction and implementation planning