Originally created 05/12/00

Study may have accidentally infected participants



Scientists may have accidentally given hundreds of Chinese research participants the very bacterial infections they were trying to prevent during a 1994 study funded and planned by the National Cancer Institute.

Susan Nayfield, who heads a cancer institute review board, said that study subjects may have been infected with H. pylori bacteria from exams with poorly cleaned endoscopes. H. pylori infections cause most stomach ulcers and might raise the risk of developing stomach cancer. China was chosen for the study because it has high rates of such infections and cancers.

Infections usually are easily treated with antibiotics, though some old cases may be more difficult to resolve, Nayfield said. It's also not known whether any serious health problems resulted from the infections, but she said "we don't expect that they have" because disease development is very slow with this bacterium.

Nayfield said that federal officials learned of the matter a few months ago.

The problem came to light last week in Madison, Wis., at a meeting of President Clinton's National Bioethics Advisory Commission, which plans soon to recommend new rules for conducting clinical trials in foreign countries.

Scientists from the United States and China are disagreeing about what to tell the study subjects. A review board that includes Chinese scientists wants to say that the reason for the infections isn't known yet; the cancer institute wants to reveal that it could be due to participating in the study.

"What do we do if they do not tell these people?" Nayfield said. "We believe that people need to be treated." The institute may give in on the disclosure issue to ensure that they are, she said.

The situation shows the problems that sometimes occur when Americans are involved with research in countries that have different cultures, and levels of education, wealth and medical care below those available in the United States.

About 30 percent to 60 percent of clinical trials the cancer institute conducts at any given time involve work in or with foreign countries, Nayfield said.

Those countries provide unique research opportunities because they have natural disasters, unusual disease outbreaks, different population characteristics and different environmental conditions from the United States. Protecting study subjects in the United States and abroad is the role of institutional review boards, or IRBs, which exist at every medical center or university that gets federal money for research.

Nayfield heads one of two IRBs at the cancer institute: the one dealing with studies that aren't conducted at the institute in Bethesda, Md.

The Chinese study started in 1988 and involved nearly the entire population of a rural province, which Nayfield would not identify. The goal was determining the prevalence of H. pylori infections. Study subjects had endoscope exams in which samples of stomach tissue were taken in 1989, in 1994, and again in 1996 or 1997, when the cancer institute started a second study to see whether taking dietary supplements could prevent such infections.

When the 1996-'97 results were analyzed, 40 percent of research participants had developed infections that hadn't been present in 1994. There are other possible explanations, but a likely scenario is that many of the new infections occurred because of the scope exams, Nayfield said.

Chinese infection control standards changed in 1991 - after the original study began - to require merely wiping the scopes with an antiseptic instead of soaking and sterilizing them between patients. The Chinese project manager hired by the cancer institute to conduct the study and to handle scientific and cultural issues didn't believe that the change threatened the safety or integrity of the experiment, so he didn't report it to the institute, Nayfield said.