The RTS,S/AS malaria candidate vaccine is being developed with the intent to be delivered, if approved, through the Expanded Programme on Immunization (EPI) of the World Health Organization. Safety, immunogenicity and efficacy of the RTS,S/AS02D vaccine candidate when integrated into a standard EPI schedule for infants have been reported over a nine-month surveillance period. This paper describes results following 20 months of follow up.

The malaria vaccine RTS,S induces antibodies against the Plasmodium falciparum circumsporozoite protein (CSP) and the concentration of Immunoglobulin G (IgG) against the repeat region of CSP following vaccination is associated with protection from P. falciparum malaria. So far, only the quantity of anti-CSP IgG has been measured and used to predict vaccination success, although quality (measured as avidity) of the antigen-antibody interaction shall be important since only a few sporozoites circulate for a short time after an infectious mosquito bite, likely requiring fast and strong binding. Quantity and avidity of anti-CSP IgG in African infants who received RTS,S/AS01E in a 0-1-2-month or a 0-1-7-month schedule in a phase 2 clinical trial were measured by enzyme-linked immunosorbent assay. Antibody avidity was defined as the proportion of IgG able to bind in the presence of a chaotropic agent (avidity index). The effect of CSP-specific IgG concentration and avidity on protective efficacy was modelled using Cox proportional hazards. After the third dose, quantity and avidity were similar between the two vaccination schedules. IgG avidity after the last vaccine injection was not associated with protection, whereas the change in avidity following second and third RTS,S/AS01E injection was associated with a 54% risk reduction of getting malaria (hazard ratio: 0.46; 95% confidence interval (CI): 0.22-0.99) in those participants with a change in avidity above the median. The change in anti-CSP IgG concentration following second and third injection was associated with a 77% risk reduction of getting malaria (hazard ratio: 0.23, 95% CI: 0.11-0.51). Change in IgG response between vaccine doses merits further evaluation as a surrogate marker for RTS,S efficacy. ClinicalTrials.gov Identifier NCT00436007 .

Malaria vaccines are considered amongst the most important modalities for potential elimination of malaria disease and transmission. Research and development in this field has been an area of intense effort by many groups over the last few decades. Despite this, there is currently no licensed malaria vaccine. Researchers, clinical trialists and vaccine developers have been working on many approached to make malaria vaccine available.

Although studies on COVID-19 vaccine hesitancy are being undertaken widely worldwide, there is limited evidence in Tanzania. This study aims to assess the sociodemographic factors associated with COVID-19 vaccine hesitancy and the reasons given by unvaccinated study participants. We conducted a mixed-method cross-sectional study with two components—health facilities and communities—between March and September 2022. A structured questionnaire and in-depth interviews were used to collect quantitative and qualitative data, respectively. A total of 1,508 individuals agreed to participate in the survey and explained why they had not vaccinated against COVID-19. Of these participants, 62% indicated they would accept the vaccine, whereas 38% expressed skepticism. In a multivariate regression analysis, adult study participants 40 years and older were significantly more likely to report not intending to be vaccinated (adjusted odds ratio [AOR], 1.28; 95% CI, 1.01–1.61; P = 0.04) than youth and middle-aged study participants between 18 and 40 years. Furthermore, female study participants had a greater likelihood of not intending to be vaccinated (AOR, 1.51; 95% CI, 1.19–1.90; P = 0.001) than male study participants. The study identified fear of safety and short-term side effects, and lack of trust of the COVID-19 vaccine; belief in spiritual or religious views; and belief in local remedies and other precautions or preventive measures as the major contributors to COVID-19 vaccine hesitancy in Tanzania. Further empirical studies are needed to confirm these findings and to understand more fully the reasons for vaccine hesitancy in different demographic groups.

: A critical impediment to efficient outbreak response is the availability of timely and complete data on cases and their linkage to care. To inform solutions to this issue, this study investigated the utility of self-testers reporting their coronavirus disease 2019 results using a mobile health platform. Our study has demonstrated that the mobile health platform is feasible; it achieved a 74.5% reporting rate, indicating a strong likelihood of data entry into the unstructured supplementary service data platform. Support from community health workers (CHWs) and healthcare professionals, particularly nurses, contributed to this success, especially among users with limited digital literacy. Specifically, 44.9% of self-test results were submitted by study participants themselves, 24.7% were submitted with the assistance of healthcare professionals, and 30.4% were submitted with the assistance of CHWs. The platform broadens the population base by increasing access and equity, allowing participation even among users without smartphones. Additionally, it integrates rapid antigen diagnostic tests with digital reporting, simplifying data processing and enabling standardized screening, real-time data capture, and effective patient follow-up. This technology also lays a foundation for pandemic preparedness in low- and middle-income countries by demonstrating the feasibility of fully integrating response loops for disease management and interventions. Future response loops could leverage artificial intelligence, machine learning, and integration with existing health surveillance systems, directly benefiting users through enhanced support.

: The rapid diagnosis of coronavirus disease 2019 (COVID-19) is critical for comprehensive public health response strategies, and self-testing with antigen rapid diagnostic tests (Ag-RDTs) presents opportunities to test in hard-to-reach communities. Therefore, we evaluated the acceptability, feasibility, and uptake of Ag-RDT self-testing at the community level in Tanzania. From June to October 2022, symptomatic individuals or those with recent contact with a known or suspected COVID-19 patient were offered assisted testing and self-testing within mining communities and at transport hubs. This study included a cross-sectional survey before and after implementation. Participants were assessed for their acceptability and uptake of the nasal Ag-RDT self-test and their preference for nasal Ag-RDT self-testing. The survey data were collected in Open Data Kit, whereas the Ag-RDT results in the community were recorded by using the COVISUSPECT Mobile Application. Data analysis was performed by using STATA and R Statistical Software. A total of 538 individuals were screened, and 454 (84.4%) consented to be tested. The preference for self-testing was relatively low (33%), and the majority of participants (67%) opted to be assisted by a healthcare professional. Of the participants who opted for testing, 149 (32.8%) were able to self-test. Generally, there was no major difference in the various assessed parameters between the baseline and end-line surveys. The results from fitting multiple logistic regression indicated that after controlling for age, participants living in Dodoma were significantly less likely to opt for self-testing (odds ratio = 0.54; P-value = 0.023) compared with those living in Dar es Salaam. There was no significant difference in self-testing between participants living in Mara and those living in Dar es Salaam (odds ratio = 0.7; P-value = 0.179). After controlling for region, older (≥40 years) participants were significantly less likely to self-test compared with participants aged 18 to <40 years (odds ratio = 0.47; P-value = 0.002). The intervention was well-accepted in all areas in which Ag-RDTs were deployed. Our findings can therefore support the Ministry of Health by increasing accessibility to severe acute respiratory syndrome coronavirus 2 testing in the hard-to-reach communities in response to the next COVID-19 wave.