Prion science is not cold fusion

EDITOR—In her news item describing the award of the 1997 Nobel prize to Stan Prusiner, Deborah Josefson stated correctly that some people are still sceptical about the prion hypothesis.1 However, Robert Rohwer is quoted as calling prions the “cold fusion of infectious diseases.” Having studied both cold fusion2-4 and prions,5 I believe that this comment is completely inappropriate and unfair.

When Fleischmann and Pons claimed that cold fusion could solve the world's energy problems with a simple table top experiment, many thousands of people all over the world tried to repeat it. The United States government set up a panel of 22 top scientists to investigate, and they concluded that there was no evidence. (Interestingly, each time the scientists announced a visit to a laboratory claiming cold fusion the cells stopped working and they never saw a working apparatus.) There were some dubious incidents.2 Quickly, almost all scientists abandoned cold fusion as they recognised it required too many miracles, with various claims being wrong by enormous factors of 10⁻⁴⁰ and 10⁻¹². A few true believers continue to have meetings, and some ask investors for support.

The question of prions is quite different as there are many serious experimental results consistent with the prion hypothesis, and these results are reproducible and can be seen on visiting laboratories. Also, predictions based on the prion hypothesis are fulfilled—for example, injecting scrapie prions into a transgenic mouse that has no prions should not and does not cause any disease. People who suggest that some form of virus (or virino, or light virus on the analogy of the neutrino) is the real cause of transmissible spongiform encephalopathies have been unable to identify it. A more appropriate comparison5 with the prion hypothesis is the equally daring quark hypothesis proposed in 1964 by Zweig and Gell-Mann. Many predictions from the quark hypothesis were verified experimentally, but a determined group of physicists refused to accept it and were able to later make the same prediction without using quarks. However, in 1974 the charm quark was discovered and all opposition to quarks collapsed.

The prion hypothesis has so much evidence in its favour that it is reasonable to accept it. It does not resemble the cold fusion story in any way.