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 How cancer metastasis happens: Researchers reveal a key mechanism
19.01.2018 | Weill Cornell Medicine

nachricht Researchers identify new way to unmask melanoma cells to the immune system
17.01.2018 | Duke University Medical Center

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: Artificial agent designs quantum experiments

On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.

We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

Im Focus: Room-temperature multiferroic thin films and their properties

Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.

Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | 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

 
Latest News

Thanks for the memory: NIST takes a deep look at memristors

22.01.2018 | Materials Sciences

Radioactivity from oil and gas wastewater persists in Pennsylvania stream sediments

22.01.2018 | Earth Sciences

Saarland University bioinformaticians compute gene sequences inherited from each parent

22.01.2018 | Life Sciences

VideoLinks Wissenschaft & Forschung
Overview of more VideoLinks >>>