Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Vaccines breed viciousness

13.12.2001


Vaccines can drive the evolution of virulent disease.
© Photodisc


Vaccinations may increase death toll.

Inadequate vaccines can the encourage emergence of nastier bugs, placing the unprotected at risk, a new mathematical model shows. The effect could undermine future vaccination programmes.

Many vaccines save people from dying of a disease, but do not stop them carrying and transmitting it. Over a few decades this may cause more virulent strains to evolve, predict Andrew Read and his colleagues of the University of Edinburgh, UK1.



In some situations, such as in areas endemic for malaria, deadlier disease strains could kill more people than vaccination saves. "Most of the time the benefits [of vaccination] will be eroded," says Read.

Vaccines for HIV, and hepatitis B and C "give most cause for concern", says immunologist Charles Bangham, of Imperial College in London. These viruses are difficult for the body’s immune system to eradicate, leaving them time to reproduce and evolve. Tearaway strains of flu also emerge regularly and evade existing vaccines.

Infections that linger in the body are more likely to meet a second bug, explains evolutionary biologist Dieter Ebert from the University of Fribourg in Switzerland. The competition drives pathogens to evolve faster, nastier killing tactics to get the most from their host.

Don’t encourage them

Vaccines that encourage evolution include those that slow a disease-causing organism’s growth or target its harmful toxin. These types are being pursued to fight diseases such as anthrax and malaria. The possibility that these might save individuals but harm populations "has not been considered before", says Ebert, and should be a factor in public-health policy.

Most existing vaccines, such as those for smallpox, polio and measles, are very effective as they use a different strategy. They stimulate a natural immune reaction which either kills off subsequent infections or blocks pathogen reproduction and transmission altogether. Read does not advocate halting such programmes. New vaccines should similarly aim to prevent pathogens getting a toehold, says Bangham; many in the pipeline do not.

Several different vaccines are being developed to fight malaria: results of clinical trials for one that interrupts the life cycle of microorganism Plasmodium falciparum were announced last week2. ’Multivalent vaccines’ that target several different parts of a pathogen or life cycle at once are the better choice, Read suggests.

References

  1. Gandon, S., Mackinnon, M. J., Nee, S. & Read, A. F. Imperfect vaccines and the evolution of pathogen virulence. Nature, 414, 751 - 756, (2001).
  2. Bojang, K. A. et al. Efficacy of RTS,S/AS02 malaria vaccine against Plasmodium falciparum infection in semi-immune adult men in The Gambia: a randomised trial. Lancet, 358, 1927 - 934, (2001).

HELEN PEARSON | © Nature News Service
Further information:
http://www.nature.com/nsu/011213/011213-14.html

More articles from Health and Medicine:

nachricht New study points the way to therapy for rare cancer that targets the young
22.11.2017 | Rockefeller University

nachricht Penn study identifies new malaria parasites in wild bonobos
21.11.2017 | University of Pennsylvania School of Medicine

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: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Corporate coworking as a driver of innovation

22.11.2017 | Business and Finance

PPPL scientists deliver new high-resolution diagnostic to national laser facility

22.11.2017 | Physics and Astronomy

Quantum optics allows us to abandon expensive lasers in spectroscopy

22.11.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>