Medicine rarely leaps forward over the course of a single year. Instead, the big advances reported in any 12-month period often have their beginnings much earlier, and their full potential may not be known for years to come. With that in mind, here’s a look at three of the most interesting medical advances reported last year that bear watching.
Re-creating 1918 flu virus may help thwart future epidemics
When two teams of scientists announced that they had re-created the 1918 “Spanish flu” virus that killed somewhere between 20 million and 50 million people, their work was hailed not only as important to the history of medicine, but as having the potential to lead to breakthroughs in understanding and preventing the bird flu strains now emerging in Asia.
In painstaking work going back a decade, scientists used tissue samples from three victims of the 1918 influenza pandemic to decipher the full gene sequence of the virus, which was unusual in its ability to spread rapidly and kill the young and healthy. Their work, published in the Oct. 6 issue of the journal Nature, found evidence that the pandemic was caused by a bird flu virus that adapted to humans through genetic changes. Further, the scientists said, a number of those genetic changes have been found in H5N1 influenza strains—the bird flu virus that has recently sparked fears of an impending influenza pandemic. The changes identified in the 1918 virus, the researchers wrote, may be important clues to how influenza viruses, including the bird flu, adapt to humans. In contrast to the 1918 virus, so far H5N1 has not spread easily from person to person.
Using this new genetic information, a different team of researchers actually reconstructed the 1918 virus. They studied what they called its “extraordinary virulence” by testing it in the lab on human lung cells and in mice. Their findings, published in the Oct. 7 issue of the journal Science, revealed that in some ways the 1918 virus acted differently than other human flu viruses, potentially explaining why it was so deadly.
Aware of the dangers of reproducing the virus, all of the researchers worked in a laboratory at the U.S. Centers for Disease Control under stringent safety precautions. But some scientists worry that the reconstructed virus may escape the lab and that publication of its full gene sequence means terrorists could make their own versions of the influenza virus. Others, however, emphasize the work’s potential to help researchers spot emerging viruses and develop vaccines and drugs to fight them.
In a joint statement, the directors of the National Institute of Allergy and Infectious Disease and the CDC, Dr. Anthony S. Fauci and Dr. Julie L. Gerberding, respectively, pointed out the work’s potential: “The findings reveal essential information to help us speed our preparation for—and potentially thwart—the next influenza pandemic. … The new studies could have an immediate impact by helping scientists focus on detecting changes in the evolving H5N1 virus that might make widespread transmission among humans more likely.”
Simple saliva tests may detect disease
Spit may not be getting the respect it deserves. In fact, doctors might one day be able to use simple saliva tests to check for cancer and other diseases, providing an alternative to blood tests. Besides being much easier to administer, these saliva tests may yield quicker results and do a better job of detecting disease in its earliest stages.
The idea of checking saliva for signs of disease is not new. Tests already use saliva to find HIV, for example. But attempts to find cancer biomarkers in saliva—changes in cells that point to the presence of the disease—took a major step forward in December 2004. That’s when scientists working at the University of California at Los Angeles reported in the journal Clinical Cancer Research that by analyzing the levels of molecules in saliva, they could distinguish between people with oral cancer and healthy people with 91 percent accuracy.
Since then, the scientists led by Dr. David Wong have repeated their research in three small studies and have begun to use the same approach to look for biomarkers for early-stage breast cancer. Next, says Dr. Wong, his group wants to determine whether saliva tests can provide early diagnosis of diseases that affect more people, such as pancreatic cancer and Type 2 diabetes. If the science holds up and interest in the tests remains strong, Dr. Wong says, the saliva test may be available to people at high risk of contracting oral cancer in as little as a year and a half, while other tests may take five years to come to market.
Dr. Len Lichtenfeld, deputy chief medical officer at the American Cancer Society, thinks that time frame is optimistic. “I suspect it will be a bit longer than one or two years before we see this used,” he says. “But having said that, this sort of research has been going on for years and sooner or later there are going to be a whole slew of these kinds of tests. And they’re going to be able to tell us whether somebody either has or is at high risk of having cancer.”
Vaccine may prevent most cervical cancer
In 2005, researchers announced dramatic results from trials of a vaccine that guards against the virus responsible for most cases of cervical cancer, a deadly disease found in some half-million women worldwide each year.
The vaccine works by making people immune to the two strains of sexually transmitted human papillomavirus (HPV) that cause about 70 percent of cervical cancer cases. It also takes aim at two different HPV strains that account for roughly 90 percent of cases of genital warts.
A vaccine against cervical cancer could have its greatest impact in the developing world, if the infrastructure exists to deliver it to women there, says Debbie Saslow, director of breast and gynecological cancer for the American Cancer Society. In industrialized nations such as the United States, she explains, most women get periodic Pap tests, which screen for cervical cancer, and this has helped reduce the number of deaths greatly. About 10,000 American women are diagnosed with cervical cancer each year and about 4,000 die. In contrast, about 250,000 women worldwide die from cervical cancer annually.
In the United States, Saslow says, the vaccine could cut down on the number of women who undergo treatment when their Pap tests falsely show abnormal results. “That’s a lot of repeat visits, a lot of time off from work, a lot of increased anxiety and a lot of cost to the health care system,” she says.
Unfortunately, approval of a vaccine will not mean the end of the Pap test—yet. Women would still need to be screened since the vaccine will not block all HPV strains that cause the cancer. In addition, Saslow points out, most men and women who have been sexually active have already been exposed to the virus. Although in most people HPV clears up on its own, women would need Pap tests to check for cases that don’t resolve themselves