Seasonal Malaria Chemoprevention Rapid Assessment Study Mozambique

Chemoprevention efficacy component

Outcomes. Primary outcomes of the CPES component are chemoprevention failure (a positive qPCR for P. falciparum parasites on day 28 after SP+AQ administration or P. falciparum positive slides at any time from day 7), prevalence of antimalarial resistance markers among chemoprevention failures and drug concentrations among chemoprevention failures. Secondary outcomes include uncomplicated malaria within the first 28 days since SP+AQ administration, participant's hospitalization within the first 28 days, severe malaria within the first 28 days , and severe anaemia levels comparisons at baseline and endline of our study period.

Sample size. Seasonal malaria chemoprevention must be well tolerated and highly effective to justify its deployment. It is therefore necessary to characterize failure (malaria breakthrough) rates accurately. A sample size of 500 children per study arm receiving SP+AQ will have 80% power to detect at least a 3% breakthrough infection rate by day 28 with a 95% confidence interval of ±1.5%, in settings where infection incidence is at least 6 infections or more per child per year and chemoprevention efficacy equals that in SMC trials in West Africa.

Recruitment and data collection. Participant selection will be carried on day 0 of the SMC implementation campaign by one trained inquirer and one phlebotomist (fieldworkers) that will follow the SMC community distributors. In each eligible household from both intervention and control arms one SMC eligible child will be selected to take part in the study . If the household has more than one SMC eligible child, only one will be randomly selected. The inquirer will be responsible for taking the informed consent form confirming the eligibility criteria that can be found below and assigning a unique ID number to each child. A baseline questionnaire will be administered to record sociodemographic data such as date of birth, gender, date of interview, and residence location. A thick blood smear will also be taken upon participant recruitment. Follow-up visits at timepoints 7, 14, 21, 28, 42 days post SMC-cycle start will be carried in selected households. The CHWs will invite the caregiver to bring their children to the health facility on the specific day to collect the blood samples. A short questionnaire exploring if the child received other treatment or experienced any disease since SP+AQ administration will be administered every time a sample is taken during the scheduled sample collection days (Day 0, 7, 14, 21, 28, 42). Heel (children aged 3-6 months) and finger (7-59 months) pricks will be collected for thick smears slides and DBS. Dose, weight, age, mid-upper arm circumference, tympanic temperature, location, time, and date will be recorded for each child on day 0, 7, 14, 21, 28 and day 42. All slides will be stained by using the Giemsa method within 24 hours of collection at the closest health facility and stored in a slide box with silica gel. Slides and DBS samples will be sent on to MORU in Bangkok, Thailand for sample analysis, where they will be analysed using qPCR methodology to detect drug concentrations, low-level sub microscopic parasitaemia and SP and AQ resistance markers.12 Drug concentration processing will take place for all SMC drugs on days 7, for sulfadoxine and AQ for day 28 and only for AQ for day 42 (as all the other drugs will have been metabolized by then ). Individual surveys on day 42 after the final DBS is taken will be conducted to determine if the child received other treatment or experienced illness over the past month of study implementation. In the event these children become febrile and receive a confirmed RDT between day 0 and day 42, they will have an additional DBS taken.

Data analysis. Once the samples have been analysed, the MORU laboratory will send the processed data back to the focal point at MC where the relevant mutations distributions and proportions will be analysed comparing parasitological efficacy between groups of mutations. Descriptive statistics of the intervention and control groups' drug levels will be calculated for the determination of any correlations with treatment outcomes, in particular drug concentrations on day 7. The focus will be on outliers with low levels of drug concentration based on the metrics described. Day 28 positivity will be correlated to antimalarial drug resistance genotype. Chemoprevention failure rates can be reported on as the cumulative failure rate using Kaplan-Meier analysis of the proportion. A time to event analysis will also be conducted to indicate duration of SMC infection protection afforded when looking at chemoprevention failures during follow up through slide and/or positive DBS samples.