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NCT Number: NCT06817421

Opportunistic Pneumococcal Immunisation Trial in MALnutrition

The goal of the OPTIMAL clinical trial is to learn if a dose of a pneumococcal conjugate vaccine (PCV) generates a good immune response in young children who are in hospital with severe acute malnutrition.

Researchers will compare an intervention group who get a dose of a PCV (Pneumosil) to a control group who get a dose of a Typhoid conjugate vaccine (Typbar TCV). To ensure all participants receive timely potential benefits, at 3 months participants in the intervention group with receive a dose of Typbar TCV, and those in the conrol group will receive a dose of Pneumosil.

Participants will be visited 4 times at their homes over six months after vaccination, with a phone review at 12 months after vaccination.

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Key information

About this study

This is a prospective, single-centre, double-blind, randomised controlled trial in 264 children aged 6-59 months hospitalised with severe acute malnutrition.

Participants will be randomised (1:1) to receive either a dose of a pneumococcal conjugate vaccine (Pneumosil, the intervention group) or a dose of a Typhoid conjugate vaccine (Typbar TCV, the control group). Stratification for randomisation will be done on (a) prior immunisation with a PCV (confirmed or unknown/unvaccinated); and (b) severity of malnurition (weight-for-height/length z-score <-4 or >=-4). Participants will be enrolled as soon as practical after admission to hospital, while randomisation and vaccine administration will occur once the participant is medically stable in the 'transition phase' of SAM care.

The primary objective is to demonstrate that immune responses to the 10 pneumococcal serotypes in Pneumosil are better in participants who receive Pneumosil, compared to those who receive Typbar TCV, when measured 28 days after vaccination.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Aged 6-59 months at the time of hospitalisation
  • Hospitalised with severe acute malnutrition (SAM, defined as any one of a, b, or c):
  • weight-for-length/height z-score <-3; or
  • middle upper arm circumference <11.5cm; or
  • bilateral pitting pedal oedema unexplained by other causes
  • Parent/carer is willing for their child to participate in the study and has provided written informed consent
  • Parent/carer is willing to comply with all study procedures outlined in the protocol, including specimen collection, for the duration of the study

Exclusion criteria

  • Known history of allergy or hypersensitivity to any component of either study vaccine, including diphtheria toxoid, or a history of anaphylactic shock.
  • Treatment with another investigational drug or other intervention in the 30 days prior to randomisation, or ongoing participation in another clinical trial.
  • Suspected primary or secondary immunodeficiency or prolonged administration (>14 days) of an immune modifying drug (including oral glucocorticoids) in the past 3 months.
  • Known terminal illness expected to result in death within 6 months.
  • Participants who, in the opinion of the site Principal Investigator, are unable to comply with the study protocol, including scheduled visits, assessments, and any other protocol-required procedures.
  • Previously enrolled in this trial.

Treatment and study plan

pneumococcal conjugate vaccine

Biological

10-valent pneumococcal polysaccharide conjugate vaccine at a dosage of 2μg for each serotype polysaccharide for 1, 5, 6A, 7F, 9V, 14, 19A, 19F, 23F, and 4μg for serotype 6B, conjugated to a carrier protein (CRM197), polysorbate 20 and aluminium phosphate as an adjuvant. Administered as an intramuscular injection of 0.5mL.

Typhoid Conjugate vaccine

Biological

Typhoid conjugate vaccine at a dosage of 25μg purified Vi capsular polysaccharide of Salmonella typhi Ty2 conjugated to Tetanus Toxoid with preservative (2-Phenoxyethanol). Administered as an intramuscular injection of 0.5mL.

Primary outcomes

  1. Serotype-specific immunoglobulin G (IgG) antibodies

    Time frame: 4 weeks after vaccination

    Pneumosil serotype-specific (1, 5, 6A, 6B, 7F, 9V, 14, 19A, 19F, 23F) immunoglobulin G (IgG) geometric mean concentrations (GMCs).

Secondary outcomes

  1. Serotype-specific IgG antibodies

    Time frame: 4 weeks and 3 months after vaccination

    Pneumosil serotype-specific IgG GMCs

  2. Proportion of participants with serotype-specific IgG antibody responses ≥ 0.35 μg/mL

    Time frame: 4 weeks and 3 months after vaccination

    Proportion of participants with Pneumosil serotype-specific IgG concentrations ≥ 0.35μg/mL

  3. Functional antibody responses

    Time frame: 4 weeks and 3 months after vaccination

    Pneumosil serotype-specific pneumococcal geometric mean opsonisation indices (GMOIs)

  4. Functional antibody responses

    Time frame: 4 weeks and 3 months after vaccination

    Proportion of participants with Pneumosil serotye-specfiic pneumococcal opsonisation indices (OIs) >8

  5. Salivary IgG antibodies

    Time frame: 4 weeks and 3 months after vaccination

    Serotype-specific salivary IgG (μg/ml) for Pneumosil serotypes and non-vaccine types 3, 4, 11A, and 18C

  6. Salivary immunoglobulin A (IgA) antibodies

    Time frame: 4 weeks and 3 months after vaccination

    Serotype-specific salivary IgA (μg/ml) for Pneumosil serotypes and non-vaccine types 3, 4, 11A, and 18C

  7. Nasopharyngeal carriage of pneumococcus

    Time frame: 3 months after vaccination

    Proportion of participants with nasopharyngeal carriage of Pneumosil vaccine-type pneumococci and their antimicrobial resistance patterns

  8. Severe acute malnutrition recovery

    Time frame: Reviewed at all study visits until completion (12 months after vaccination)

    Weight-for-height/length z-score >= -2 or MUAC >12.5cm

  9. Re-hospitalisation

    Time frame: 3 months and 12 months after vaccination

    Any repeat admission to hospital as confirmed by medical records

  10. Mortality

    Time frame: 3 and 12 months after vaccination

    Deaths as reported. Cause of death determined from review of medial records.

  11. Composite illness or mortality

    Time frame: Reviewed at all study visits until completion (12 months after vaccination)

    Repeat hospitalisation(s) or death.

  12. Salmonella Typhi antibodies

    Time frame: 4 weeks and 3 months after vaccination for all participants, plus 4 months and 6 months after vaccination for participants in the control arm

    Proportion of paticipants with >4 fold rise (compared to pre-vaccination) of Salmonella Typhi anti-Vi IgG geometric mean titres (GMTs)

Study contacts

Contact information is provided by the study sponsor or research team.

Jane N Nelson, Bachelor of Nursing

CONTACT

[email protected]

+61889468600

Nicholas S. S. Fancourt, PhD

CONTACT

[email protected]

+61889468600

Sponsors and collaborators

Lead sponsor

Nick Fancourt

Other

Collaborators

  • Murdoch Childrens Research Institute
  • The University of Western Australia
  • Timor-Leste Ministry of Health
  • University of Edinburgh

Registry information

Official study title

Immunogenicity of Opportunistic Pneumococcal Conjugate Vaccination (Pneumosil®) Versus Control (Typhoid Conjugate Vaccine, Typbar TCV®) in Children Aged 6-59 Months Hospitalised With Severe Acute Malnutrition: a Single-centre, Double-blind, Randomised Controlled Trial in Timor-Leste

Acronym: OPTIMAL

Important dates

Study start
2026
Primary completion
2028
Study completion
2029
First posted
Feb 10, 2025
Registry last updated
Dec 18, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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