R21/MATRIX-M MALARIA VACCINE

Source: Hindu

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Context

• The Serum Institute of India (SII) has begun exporting the R21/Matrix-M malaria vaccine to Africa.
• This vaccine was developed in collaboration with the University of Oxford and Novavax's Matrix-M adjuvant.
• It represents a significant advancement in the global fight against malaria, particularly in protecting children in malaria-endemic regions.

Details

Overview of Malaria

• Malaria is a life-threatening disease caused by parasites that are transmitted to people through the bites of infected female Anopheles mosquitoes.
• Despite significant progress in reducing malaria incidence and mortality, it remains a major public health challenge, particularly in tropical and subtropical regions.

Classification and Causative Agents

• Domain: Eukaryota
• Kingdom: Protista
• Phylum: Apicomplexa
• Class: Aconoidasida
• Order: Haemospororida
• Family: Plasmodiidae
• Genus: Plasmodium
• Species:
  • Plasmodium falciparum (most deadly)
  • Plasmodium vivax
  • Plasmodium ovale
  • Plasmodium malariae
  • Plasmodium knowlesi (less common)

Life Cycle of Plasmodium

• Sporogonic Cycle (in Mosquito): Infected mosquito bites a human, injecting sporozoites into the bloodstream.
• Exo-erythrocytic Cycle (in Human Liver)
  • Sporozoites travel to the liver and infect hepatocytes.
  • Schizogony occurs, producing merozoites.
• Erythrocytic Cycle (in Human Blood)
  • Merozoites infect red blood cells.
  • Merozoites undergo asexual reproduction, producing more merozoites.
  • Some merozoites differentiate into gametocytes.
• Transmission Cycle
  • Another mosquito bites an infected human, ingesting gametocytes.
  • Gametocytes develop into sporozoites in the mosquito, continuing the cycle.

Symptoms

• Uncomplicated Malaria:
  • Fever
  • Chills
  • Headache
  • Sweats
  • Fatigue
  • Nausea and vomiting
• Severe Malaria:
  • Cerebral malaria (seizures, coma)
  • Severe anemia
  • Hemoglobinuria
  • Acute respiratory distress syndrome (ARDS)
  • Multiple organ failure

Treatment

• Uncomplicated Malaria:
  • Artemisinin-based combination therapies (ACTs)
  • Chloroquine (for P. vivax and P. ovale in chloroquine-sensitive regions)
• Severe Malaria:
  • Intravenous artesunate
  • Intravenous quinine or quinidine
  • Follow-up with ACTs

Prevention and Control

• Vector Control:
  • Insecticide-treated bed nets (ITNs)
  • Indoor residual spraying (IRS)
• Chemoprophylaxis:
  • Antimalarial drugs for travelers to endemic areas (e.g., doxycycline, mefloquine, atovaquone/proguanil)
• Vaccination:
  • RTS,S/AS01 (Mosquirix): WHO-recommended for children in high-transmission areas.
  • R21/Matrix-M: Recently approved, showing high efficacy.

Epidemiology

• Global Burden:
  • Approximately 229 million cases and 409,000 deaths in 2019.
  • Sub-Saharan Africa accounts for over 90% of malaria cases and deaths.
• High-Risk Groups:
  • Children under 5 years
  • Pregnant women
  • Non-immune travelers

Sources:

Hindu

PRACTICE QUESTION Q.  Discuss the current status of malaria in India, highlighting the key strategies implemented by the government to combat the disease. What challenges persist in achieving malaria elimination, and how can these be addressed? (150 Words)