Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Meningitis: effectiveness of preventive vaccination demonstrated

06.06.2007
Meningitis epidemics caused by the pathogen Nesseiria meningitis (or meningococcus) provoke high mortality in children and young people under 20 years of age in sub-Saharan Africa. They rage during periods of drought from January to April, in the area known as the “Meningitis Belt”

Two types of vaccine are currently on the market: the polysaccharide vaccine and the conjugated vaccine. The polysaccharide form, elaborated from a sugar present at the surface of the meningococcus provides only partial, temporary immunity in very young children (2).

The conjugated vaccine, however, is based on a combination between this same sugar and an antigenic protein and renders an effective durable immunity. It could therefore be used in a routine preventive vaccination campaign. But it is costly. Its high price, at 11 to 22 euros per dose, means it remains inaccessible for African countries. These have available only the polysaccharide vaccine, less expensive at 0.3 to 0.5 euro, but which, because of its low immunity capacity, is generally kept only for emergency vaccinations, when epidemics occur.

IRD researchers have been running a follow-up study of the people of the Niakhar region (located 150 km from Dakar, in Senegal) for more than 40 years. They looked into the question of the ability of the polysaccharide vaccine to prevent the occurrence of meningitis cases during epidemics in the course of subsequent years. To do that, they made use of results of two vaccination campaigns conducted with this vaccine by the Senegalese health services. One of these was run in 1996 in 8 of the 30 villages that make up the Niakhar region, the other in 1999, in the whole of the study area, hit be a series of epidemics between 1998 and 2000.

Using quarterly censuses carried out since 1983, the researchers collected then analysed data on children’s state of health and vaccine status. They could therefore make comparisons between the different villages regarding the number of cases of meningitis that broke out, in particular in the years that followed the 1996 vaccination campaign (3).

Their investigation revealed that in the villages vaccinated at that date, two to three times fewer subjects were recorded as suffering from the disease. The polysaccharide vaccine could help avoid up to 72% of cases in subsequent epidemics.

These results speak in favour of adopting a strategy of routine vaccination using this vaccine – whenever no other vaccine is available – in order to prevent meningococcus meningitis epidemics in this region of Africa. However, a conjugated vaccine which should be sold at less than 1$ (0.80 euro) per dose, is under development. Thanks to the full, durable immunity it confers right from early childhood, it is an ideal tool for a preventive vaccination strategy. Clinical trials initiated in 2006, notably in Niakhar, are continuing for a further 2 years in order to make sure that no undesirable side-effects occur after administration.

Marie Guillaume | EurekAlert!
Further information:
http://www.ird.fr

More articles from Health and Medicine:

nachricht Nanoparticles as a Solution against Antibiotic Resistance?
15.12.2017 | Friedrich-Schiller-Universität Jena

nachricht Plasmonic biosensors enable development of new easy-to-use health tests
14.12.2017 | Aalto University

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First-of-its-kind chemical oscillator offers new level of molecular control

DNA molecules that follow specific instructions could offer more precise molecular control of synthetic chemical systems, a discovery that opens the door for engineers to create molecular machines with new and complex behaviors.

Researchers have created chemical amplifiers and a chemical oscillator using a systematic method that has the potential to embed sophisticated circuit...

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Engineers program tiny robots to move, think like insects

15.12.2017 | Power and Electrical Engineering

One in 5 materials chemistry papers may be wrong, study suggests

15.12.2017 | Materials Sciences

New antbird species discovered in Peru by LSU ornithologists

15.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>