RTSS Vaccine and PBO Net Impact on Malaria Infection and Transmission in Malawi

NCT04327440 | Completed

• 2 other identifiers: 000026623U19AI089683-10S1
• Study Type: observational
• Target: 1,691
• Locations: 1 country
• Sites: 1

Brief Summary

The overall goal of this study is to assess the impact of RTS,S (malaria) vaccination and PBO nets on malaria infection and transmission, independently and how they interact when they are introduced together. The specific objectives for the study are as follows:

1. 1.To estimate the impact of PBO nets and RTS,S vaccine on Plasmodium infection prevalence and transmission, independently and how they interact when they are introduced together in Malawi (Phase 1).
2. 2.To assess the feasibility of evaluating the impact of RTS,S vaccine and PBO nets independently in a larger scale future study.

Conditions

Malaria, Malaria Vaccine, Insecticide-treated Bednets

Outcome Measures

Primary Outcomes (2)

• Malaria infection prevalence

  Comparison of malaria infection prevalence in RTS/S cohorts compared to cohorts not exposed to RTS,S

  6 months/cohort, 4 cohorts in Phase 1

• Anopheles species abundance

  Comparison of Anopheles captured in households with PBO nets compared to household with conventional nets

  6 months/cohort, 4 cohorts in Phase 1

Secondary Outcomes (5)

• Gametocyte prevalence

  6 months/cohort, 4 cohorts

• Net usage

  6 months/cohort, 4 cohorts

• Serological markers of immunity and exposure

  6 months/cohort, 4 cohorts

• Anopheles gravidity rates

  6 months/cohort, 4 cohorts

• Anopheles sporozoite rates

  6 months/cohort, 4 cohorts

Study Arms (4)

Nyambi, rainy season

250 children of age-eligible for RTS,S vaccine (7-18 months) 500 siblings (\>18 months, \< 10 years of age) The duration of the cohort is six months.

Biological: RTS,S/AS01 malaria vaccine; Other: PBO bed nets

Nyambi, dry season

250 children of age-eligible for RTS,S vaccine (7-18 months) 500 siblings (\>18 months, \< 10 years of age) The duration of the cohort is six months.

Biological: RTS,S/AS01 malaria vaccine; Other: PBO bed nets

Kalembo, rainy season

250 children of age-eligible for RTS,S vaccine (7-18 months) 500 siblings (\>18 months, \< 10 years of age) The duration of the cohort is six months.

Kalembo, dry season

250 children of age-eligible for RTS,S vaccine (7-18 months) 500 siblings (\>18 months, \< 10 years of age) The duration of the cohort is six months.

Interventions

RTS,S/AS01 malaria vaccine BIOLOGICAL

Malaria vaccine: RTS,S is a subunit vaccine that includes a portion of the circumsporozoite protein (CSP) co-expressed with Hepatitis B surface antigen combined with an adjuvant. The Phase 3 trial of three doses administered to 5-17-month-olds confirmed moderate protection, with overall efficacy estimates of 50.4% against clinical malaria and 34.8% against severe malaria after three doses. Efficacy, which waned over time, was marginally improved by boosting at 18 months. The European Medicines Agency adopted a positive scientific opinion of the vaccine for use outside of the European Union. The World Health Organization has created the Malaria Vaccine Implementation Program (MVIP) and selected Malawi as one of the sites to explore the feasibility, efficacy and safety of RTS,S vaccination in the context of routine use.

Also known as: RTS,S

Nyambi, dry season; Nyambi, rainy season

PBO bed nets OTHER

PBO nets: The PBO nets represent a new formulation of insecticide-treated bed nets with a chemical synergist, piperonyl butoxide (PBO), designed to enhance the insecticidal effect of pyrethroids. They seem to be helpful in areas like Malawi where insecticide-resistance is increasing. PBO inhibits the enzyme that detoxifies the pyrethroid, allowing the pyrethroid to act on the mosquito. The impact of PBO net use was also detectable in key entomological measures including Anopheles density, sporozoite rate and entomological inoculation rates. Following these promising preliminary results in Tanzania, Malawi's National Malaria Control Program (NMCP) is piloting the use of PBO-nets iin one of our two study sites, presenting us with the opportunity to study the effectiveness of these nets in the context of real-world program setting

Nyambi, dry season; Nyambi, rainy season

Eligibility Criteria

• Age: 7 Months - 10 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Child (0-17)
• Sampling Method: Probability Sample

Study Population

Children whose age is between 7 and 18 months, which indicates they could receive at least 3 RTS,S doses, will be eligible to participate. Following informed consent from parents/guardians, up to two children who are 18 months but ≤10 years of age, from the same household as the vaccine-eligible child, will also be enrolled. Only households whose families intend to stay in the area for at least six months and whose eligible children will also be expected to use an assigned health center for child vaccinations will be eligible to participate.

You may qualify if:

• Children aged 7 to 18 months of age (age-eligible for at least 3 doses of RTS,S doses) OR being one of not more than two children living in the household of an enrolled age-eligible child and being \>18 mos and \< 10 years of age.
• Not on cotrimoxazole prophylaxis for HIV infection
• Weight \>5 kg
• Permanent residence of Health Centre (HC) catchment area
• Residence within 10 km from the HC
• Written informed consent from parent/guardian for the child to participate in the study

You may not qualify if:

• Non-residents of the catchment area and visitors to the study area will be excluded because the study requires follow-up for at least 6 months and access to interventions such as conventional, PBO nets and malaria vaccination.

Sponsors & Collaborators

• Michigan State University: lead
• Kamuzu University of Health Sciences: collaborator
• University of Maryland, Baltimore: collaborator
• Boston University: collaborator
• National Institute of Allergy and Infectious Diseases (NIAID): collaborator

Study Sites (1)

University of Malawi College of Medicine

Blantyre, 3, Malawi

Location

Biospecimen

Retention: SAMPLES WITHOUT DNA

Dried blood spots to identify malaria infection (asexual parasites) and transmission potential (sexual stage parasites). Plasma to assess serological measures of exposure and antimalarial immunity

MeSH Terms

Conditions

Malaria

Condition Hierarchy (Ancestors)

Protozoan Infections; Parasitic Diseases; Infections; Mosquito-Borne Diseases; Vector Borne Diseases

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor

Study Record Dates

• First Submitted: March 27, 2020
• First Posted: March 31, 2020
• Study Start: February 4, 2020
• Primary Completion: June 30, 2021
• Study Completion: June 30, 2021
• Last Updated: January 13, 2026

Record last verified: 2025-09

Data Sharing

• IPD Sharing: Will not share

Locations

MA (1)