Malaria case management: Plasmodium vivax malaria – A field guide

What this guideline says

GMJ summary

This field guide provides comprehensive operational guidance for implementing the updated WHO recommendations on Plasmodium vivax malaria case management, particularly the introduction of near-patient glucose-6-phosphate dehydrogenase (G6PD) testing and new treatment options including tafenoquine and high-dose primaquine. The document is designed to support national malaria programmes, clinicians, and public health professionals in planning, implementing, and monitoring radical cure strategies that eliminate both blood-stage parasites and dormant liver-stage hypnozoites.

The central message is that radical cure of P. vivax malaria requires both a schizontocide (chloroquine or ACT) to clear blood-stage infection and an 8-aminoquinoline (primaquine or tafenoquine) to eliminate hypnozoites and prevent relapse. G6PD testing is essential to guide safe administration of these medicines, as both primaquine and tafenoquine can cause acute haemolytic anaemia in G6PD-deficient individuals. Semi-quantitative G6PD testing enables identification of patients with ≥70% of normal G6PD activity who can receive single-dose tafenoquine or high-dose 7-day primaquine, while qualitative testing guides lower-dose 14-day primaquine regimens.

The guide emphasizes that successful implementation requires integrated planning across supply chain management, health worker training, patient counselling, pharmacovigilance systems, and monitoring and evaluation frameworks. Lessons learned from pilot implementations in Brazil, Thailand, Cambodia, Peru, Indonesia, and Papua New Guinea demonstrate the operational feasibility of G6PD testing and radical cure in real-world settings, while highlighting the importance of quality training, supportive supervision, and community engagement.

Key points

For clinicians — doses and thresholds as stated in the guideline

1. Blood-stage treatment: Use chloroquine in areas with chloroquine-susceptible infections or ACT in resistant areas; tafenoquine must be given with chloroquine only, primaquine can be given with either
2. G6PD testing mandatory before tafenoquine or high-dose primaquine: Semi-quantitative tests required to identify patients with ≥70% of normal G6PD activity; qualitative tests identify <30% activity (deficient)
3. Tafenoquine 300 mg single dose (adults >35 kg) or weight-based dosing (children ≥2 years, 10–35 kg) only for patients with ≥70% normal G6PD activity; not for pregnant/breastfeeding women
4. High-dose primaquine 7 mg/kg total: either 1 mg/kg/day for 7 days (requires ≥70% G6PD activity) or 0.5 mg/kg/day for 14 days (requires ≥30% G6PD activity)
5. G6PD intermediate patients (30–70% activity): receive primaquine 0.5 mg/kg/day for 14 days; G6PD deficient (<30%): primaquine 0.75 mg/kg weekly for 8 weeks with strict medical supervision
6. Acute haemolytic anaemia typically occurs days 2–5 after starting 8-aminoquinolines; symptoms include dark ('cola-coloured') urine, pallor, jaundice, severe fatigue, breathlessness
7. Patient counselling essential: explain G6PD testing purpose, treatment options, importance of adherence (for primaquine), haemolysis symptoms, and when to seek care immediately
8. Pharmacovigilance and follow-up: monitor for adverse drug reactions on days 3–5, assess adherence, confirm parasite clearance day 28, and evaluate recurrence prevention

Summary of considerations for 8-aminoquinoline administration

Table extracted from the guideline

Source: World Health Organization, Malaria case management: Plasmodium vivax malaria – A field guide. Reproduced in summary form.

What changed in this edition

Versus the previous edition

• Tafenoquine recommended as alternative to primaquine for preventing relapses in patients ≥2 years with ≥70% G6PD activity receiving chloroquine (2024 recommendation)
• Semi-quantitative near-patient G6PD tests with fixed thresholds for deficient (<30%), intermediate (30–70%), and normal (≥70%) activity recommended to guide treatment (2024)
• High-dose primaquine regimen (7 mg/kg total) recommended: 1 mg/kg/day for 7 days (≥70% G6PD activity) or 0.5 mg/kg/day for 14 days (≥30% G6PD activity) to prevent relapse (2024)
• Qualitative near-patient G6PD tests recommended to distinguish G6PD above or below 30% threshold, enabling 0.5 mg/kg/day primaquine for 14 days or 7 days (2024)
• Good practice statement added: G6PD status should be used to guide administration of either primaquine or tafenoquine for preventing relapse (2024)

From the guideline

Verbatim

“Radical cure is required to eliminate both blood-stage and latent liver-stage infection, thereby curing acute malaria as well as preventing relapse.”

Editor’s perspective

Why this matters for Georgia and the region

Applicability

Georgia and the South Caucasus

Questions this guideline answers

Quick answers

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