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MANILA, Philippines鈥擫atest results of a vaccine clinical trial offered a gleam of hope in effectively combatting malaria, a mosquito-borne disease that kills a child every minute.
The latest clinical trial for a candidate malaria vaccine, R21/Matrix-M, yielded encouraging results鈥攚hich scientists described as a huge breakthrough, emphasizing the vaccine鈥檚 potential to save millions of lives worldwide and to eradicate the disease eventually.
Malaria is a life-threatening disease caused by parasites transmitted to people through the bites of infected female Anopheles mosquitoes.
The World Health Organization (WHO) estimated that there were 241 million cases of malaria across the globe in 2020. The number of malaria deaths meanwhile stood at 627,000 that same year.
However, malaria is a preventable and curable disease. Currently, it is treated with prescription drugs to kill the parasite. Among the common antimalarial drugs include:
- Chloroquine phosphate: preferred treatment for any parasite that is sensitive to the drug.
- Artemisinin-based combination therapies (ACTs): a combination of two or more drugs that work against the malaria parasite in different ways.
- Atovaquone-proguanil (Malarone)
- Quinine sulfate (Qualaquin) with doxycycline (Oracea, Vibramycin, others)
- Primaquine phosphate
Last year, WHO approved the first-ever malaria vaccine developed by British drug maker GlaxoSmithKline called the RTS, S, or Mosquirix.
Read: WHO endorses first-ever vaccine against malaria
However, with the recent developments achieved by the R21 vaccine, some scientists believe the Oxford malaria vaccine may offer even greater hope鈥攁nd could be an effective weapon in the fight against malaria.
Promising clinical trial results
Phase 2b of the randomized, controlled, and double-blind trial for the candidate malaria vaccine, R21/Matrix-M, was conducted at the Clinical Research Unit of Nanoro (CRUN) / Institut de Recherche en Sciences de la Sant茅 (IRSS) in Burkina Faso鈥攁 country where malaria infections are seasonal.
A total of 450 children aged between 5 and 17 months were recruited for the clinical trial. At least 409 received a booster dose of the R21/Matrix-M鈩� vaccine鈥攖he same as their primary series of vaccinations鈥攊n June 2020, prior to the peak malaria season.
GRAPHIC: Ed Lustan
The participants, who received the R21/Matrix-M鈩� vaccine as a booster, were randomly assigned to two groups鈥攚ith either a low dose or high dose of the Matrix-M adjuvant.
Results of the trial, which were published last September 7 in The Lancet Infectious Diseases, showed vaccine efficacy of 80 percent in those with higher strength booster dose, and 70 percent in the lower strength booster dose group, a year after the vaccine booster dose was administered.
No serious adverse events related to the vaccine were also noted.
鈥淭his is a parasite we鈥檙e trying to vaccinate against. It鈥檚 not a virus. It鈥檚 got thousands of genes. [So it鈥檚] complex to design a vaccine,鈥� Adrian Hill, the director of the Jenner Institute at the University of Oxford and co-author of The Lancet paper, said in a report published by the Voice of America (VOA).
鈥淥ver 100 have been in clinical trials and this looks like the best data so far. So we鈥檙e excited,鈥� he added.
The results of the clinical trial also shown that the R21 vaccine has continued to meet WHO鈥檚 Malaria Vaccine Technology Roadmap goal of a vaccine with at least 75 percent efficacy.
Read: Oxford malaria vaccine data bodes well for effort to combat deadly disease
Still, public health officials will require results from a bigger trial before the R21鈥檚 safety and utility are confirmed. Promising results from a larger trial鈥攚ith more participants spread across four African countries鈥攚ill also be required before the vaccine can be rolled out on a larger scale.
GRAPHIC: Ed Lustan
鈥淚t is fantastic to see such high efficacy again after a single booster dose of vaccine. We are currently part of a very large phase III trial aimed at licensing this vaccine for widespread use next year,鈥� said Halidou Tinto, Professor in Parasitology, Regional Director of IRSS in Nanoro, and the trial Principal Investigator.
According to the University of Oxford, results of the key ongoing Phase III licensure trial鈥攚hich will assess large-scale safety and efficacy in 4,800 children aged five to 36 months across four African countries鈥攁re expected to be released later this year.
鈥淭here is still more work to be done. But I think this is very positive news,鈥� said Matshidiso Moeti, WHO鈥檚 regional director for Africa.
About R21 Matrix-M vaccine
The R21 Matrix-M malaria vaccine candidate was created by the University of Oxford. It includes saponin-based Matrix-M adjuvant by Novavax AB鈥攖he same biotechnology company that manufactures the Novavax COVID vaccine.
Read: Novavax COVID-19 vaccine gets emergency use approval in PH
According to the US Centers for Disease Control and Prevention (CDC), an adjuvant is 鈥渁n ingredient used in some vaccines that helps create a stronger immune response in people receiving the vaccine. In other words, adjuvants help vaccines work better.鈥�
The R21 Matrix-M malaria vaccine is licensed to the Serum Institute of India.
Although it was not the first malaria vaccine created, it quickly showed promising results from different tests and trials.
In April last year, the R21/Matrix-M became the first antimalarial vaccine to achieve the WHO-specified 75 percent efficacy goal鈥攁head of Mosquirix, which was reportedly nearly 63 percent effective against clinical malaria based on late-stage trial data.
The following month, The Lancet published a study stating that the R21/MM malaria vaccine appears safe and very immunogenic in African children鈥攁nd with promising high-level efficacy (77 percent).
According to Alister Craig from the Liverpool School of Tropical Medicine, results of the latest clinical trial for the R2 Matrix-M vaccine suggest that the Oxford shot is a step forward from Mosquirix in improving efficacy and the retention of immunity.
PH鈥檚 goal: 0 cases by 2030
Last year, the Department of Health (DOH) announced the Philippine government鈥檚 target in the National Malaria Control and Elimination Program (NMCEP): to reach zero malaria cases in the country by 2030.
According to Proclamation No. 1168 signed by then-President Gloria Macapagal Arroyo in 2006鈥攚hich declares November as Malaria Awareness Month鈥攎alaria was then the 8th leading cause of death in the country mostly affecting pregnant women, children, and indigenous population groups.
GRAPHIC: Ed Lustan
However, the number of malaria cases in the country has been going down since then.
On April 26, 2021, the DOH said the country鈥檚 malaria incidence declined by 87 percent from 48,569 in 2003 to 6, 210 cases in 2020.
The number of deaths caused by malaria has also declined by 98 percent, from 162 deaths in 2003 to only three deaths in 2020.
鈥淎long with this is the shrinking geographic extent of malaria, with 60 provinces officially declared by the DOH as malaria-free, and an additional 19 provinces having reached malaria elimination phase with zero local transmission, waiting to be assessed and declared malaria-free provinces,鈥� the DOH said.
鈥淎t the end of 2020, only 126 barangays from 2 provinces in the country have recorded local malaria transmission,鈥� it added.
READ: Malaria awareness month: Numbers show sharp decline in PH cases
Some of the symptoms of malaria that might manifest at the beginning of the disease, according to the US CDC, are fever, sweats, chills, headaches, malaise, muscles aches, nausea, diarrhea, and vomiting.
Malaria can also lead to anemia and jaundice, which causes the color of the skin and eyes to turn yellow, due to the loss of red blood cells.
The incubation period takes anywhere from seven to 30 days.
鈥淚f not promptly treated, the infection can become severe and may cause kidney failure, seizures, mental confusion, coma, and death,鈥� the US CDC added.
How it can help PH reach its target
Although the R21 Matrix-M malaria vaccine is still under clinical trials, it could potentially play a role in the Philippines鈥� zero malaria goal鈥攅specially with the help of the Serum Institute of India.
Hill said that the Serum Institute of India has committed to manufacturing at least 200 million doses of the Oxford malaria vaccine annually in the coming years.
鈥淪erum Institute is committed to global disease burden reduction and disease elimination strategies by providing high volume, affordable vaccines,鈥� Dr. Cyrus Poonawalla and Mr. Adar Poonawalla, chairman and CEO of the Serum Institute of India, also said in a statement.
鈥淲e are highly confident that we will be able to deliver more than 200 million doses annually in line with the above strategy as soon as regulatory approvals are available.鈥�