Malaria vaccine offers partial protection: final results

2015-04-24 12:21

(Shutterstock)

Multimedia   ·   User Galleries   ·   News in Pictures Send us your pictures  ·  Send us your stories

Paris - The world's most advanced malaria candidate vaccine offers young children partial protection that wanes with time, but could shield millions against the deadly parasite, its developers said on Friday.

Researchers published the final results of a years-long trial with the drug RTS,S in The Lancet medical journal.

"We finally have in our sights a candidate vaccine that could have a real impact on this terrible disease that affects many children during their first years of life," principal investigator Kwaku Asante said in a statement.

"The large number of children affected by malaria, sometimes several times per year, means that this vaccine candidate, if deployed correctly, has the potential to prevent millions of cases of malaria," Asante added.

The trial saw nearly 15 500 children in seven African countries, one group aged five to 17 months and the other six to 12 weeks given three initial vaccine doses over a period of three months.

Some received a booster shot 18 months later, the effects of which were reported for the first time on Friday.

The extra dose, it turned out, "restores some of the immunity lost after the first series of injections," according to study co-author Brian Greenwood of the London School of Hygiene and Tropical Medicine.

"Unfortunately, this is not as big an effect as that seen with some other vaccines," like that against measles, he told AFP by email.

Melinda and Bill gates

In spite of the drug's partial effect, it remains the most clinically-advanced vaccine against malaria, which kills about 1 200 children in sub-Saharan Africa on average per day.

Compared to children not given the vaccine, those in the older age group enjoyed a protection rate of about 50%in the first year against clinical or non-life threatening malaria, dropping to 28% after four years, said the study released on the eve of World Malaria Day on Saturday.

The extra dose increased the protection rate at year four to 36%.

The comparable figures for the younger group was 18% after three years, and 26% with the booster.

For severe malaria, those in the older group who received an extra shot enjoyed a protection rate of 32 percent after four years, said Greenwood, but without a booster the vaccine offered no noticeable defence.

Developed with the backing of drug firm GlaxoSmithKline and non-profit group PATH Malaria Vaccine Initiative, with funding from the Bill & Melinda Gates Foundation, RTS,S is the first candidate malaria vaccine to reach Phase III clinical testing, the final stage before market approval.

The mosquito-borne disease kills some 600 000 people per year, more than 75% of them children under five, according to the World Health Organisation (WHO).

Approached for comment on the study, University of Oxford tropical medicine professor Nick White said the findings were both encouraging and disappointing.

"We at last have a vaccine against malaria that works, but it doesn't work as well as originally hoped," he said.

And it was not clear if the findings warrant a widespread vaccination campaign.

"It depends on the costs and the benefits," said White. "If there is enough money, yes. If this will draw money away from control measures of proven value [drugs and bed nets] then no."

Meningitis risk?

The European Medicines Authority is evaluating whether or not the drug can be licenced for use, and the WHO is preparing policy recommendations for what could be the first licenced vaccine against a parasitic disease.

The trial did not answer the question of how often a booster would be needed, or how many times it would be safe to administer one.

"The results available so far suggest that this might need to be done every year or every two years," Greenwood said.

Some two dozen vaccinated children developed meningitis, but the researchers said this could be coincidental, an issue that requires further investigation.

They also noted that children who did not receive the booster ran a higher risk of severe malaria towards the end of the study period.

The killer parasite has developed resistance to successive treatments, and insecticide-treated bed nets remain one of the most effective prevention methods.

Read more on:    health

Join the conversation!

24.com encourages commentary submitted via MyNews24. Contributions of 200 words or more will be considered for publication.

We reserve editorial discretion to decide what will be published.
Read our comments policy for guidelines on contributions.

24.com publishes all comments posted on articles provided that they adhere to our Comments Policy. Should you wish to report a comment for editorial review, please do so by clicking the 'Report Comment' button to the right of each comment.

Comment on this story
0 comments
Comments have been closed for this article.

Inside News24

 
/News

Book flights

Compare, Book, Fly

Traffic Alerts
Traffic
There are new stories on the homepage. Click here to see them.
 
English
Afrikaans
isiZulu

Hello 

Create Profile

Creating your profile will enable you to submit photos and stories to get published on News24.


Please provide a username for your profile page:

This username must be unique, cannot be edited and will be used in the URL to your profile page across the entire 24.com network.

Settings

Location Settings

News24 allows you to edit the display of certain components based on a location. If you wish to personalise the page based on your preferences, please select a location for each component and click "Submit" in order for the changes to take affect.




Facebook Sign-In

Hi News addict,

Join the News24 Community to be involved in breaking the news.

Log in with Facebook to comment and personalise news, weather and listings.