As reported in the journal Clinical Infectious Diseases, Dr. Ellen M. Tidaldi, from Temple University Hospital in Philadelphia, and colleagues analyzed hepatitis A and B vaccination practices at various HIV outpatient sites.

Of 612 patients eligible for hepatitis B vaccination, only 198 received at least one dose. Among 716 patients eligible for the hepatitis A vaccine, only 167 received at least a dose.

Hepatitis B vaccination was associated with clinical practice factors as well as patient characteristics. "For hepatitis B, the rates of vaccine administration were somewhat better for those who had more frequent office visits and for those whose HIV risk category was high-risk heterosexual sex," the researchers report.

The investigators were not able to identify factors that predicted hepatitis A vaccination.

"The inclusion of routine viral hepatitis screening, vaccination, and postvaccination testing for any new patients to a clinical practice needs to be emphasized," the authors conclude.

SOURCE: Clinical Infectious Diseases, May 2004.

NEW YORK (Reuters Health) - Treating gay men who think they may have been exposed to HIV -- a strategy known as postexposure chemoprophylaxis (PEP) -- does not increase high-risk behavior, according to research conducted in Brazil.

Dr. Mauro Schechter from Universidado Federal de Rio de Janeiro, and colleagues, examined the acceptability, safety, and impact on sexual behavior of anti-HIV treatment after sexual exposure.

The study involved 200 gay men. Sixty-eight participants took PEP, consisting of the anti-HIV drugs lamivudine and zidovudine in a fixed-dose combination tablet, after high-risk activity, the authors report. Eighty-six did not take PEP despite high-risk behavior at least once during the study, and 46 denied high-risk behavior during the study.

The average number of partners was the same in the 6 months before the study and in the 6 months before the final study visit for the subjects who took PEP and those who did not, the results show.

On average, high-risk sexual activities declined over time for both groups, the authors report in a specialty AIDS journal.

Eleven subjects did become infected with HIV during the study, which is about the number that would be expected for the risk profile of this group.

"This study was originally designed (in 1997) as a pilot study to look at behavioral changes, in preparation for a larger study to look at efficacy," Schechter told Reuters Health. "Since that time, many things have changed and I believe it would be unethical to conduct an efficacy trial now."

Thus, he added, "I believe PEP will become one more thing we do in medicine because we believe it works, although formal proof is lacking and will likely never be available," he said.

"PEP is safe...and most people don't start practicing unsafe sex just because PEP is available," Schechter concluded. However, "PEP is unlikely to have any major impact on the epidemic, and thus has to be viewed just as one more tool to prevent infection."

SOURCE: Journal of Acquired Immune Deficiency Syndromes, April 15, 2004.

By Karla Gale

NEW YORK (Reuters Health) - Lactobacillus, a benign gut microbe that helps prevent more serious infections such as diarrhea in children, could become a weapon in the war on AIDS.

Colonizing an infant's digestive tract with the so-called "probiotic" may protect them from being infected with HIV present in breast milk, according to a report at the American Society for Microbiology general meeting in New Orleans.

With the success of treating HIV-infected mothers before delivery to prevent transmission of the virus to the baby, breast-feeding is now the major route by which infants do become infected in Africa.

However, anti-HIV drugs to prevent infection cannot be used in infants, Dr. Lin Tao explained. "So we sought to block HIV transmission from mother to child using a more innovative approach," added Tao, of the University Illinois at Chicago College of Dentistry.

Lactobacillus, commonly found among the normal bacteria populating the intestines, seemed to be such an option.

The researchers obtained saliva samples from more than 100 healthy volunteers, from which they isolated 170 strains of Lactobacillus. Testing showed that nine were probably capable of binding to HIV. One in particular -- L. fermentum OLB-19a -- stopped HIV from infecting immune cells, the investigators found.

Because "the stomach and intestine is where active absorption of milk takes place, it will be very important to have the bacteria in the oral cavity and throughout the intestinal tract," Tao explained. To that end, his group is attempting to develop a formulation of Lactobacillus that can be administered to infants.

Their current research was funded by the National Institutes of Health, the researcher noted. The group's challenge now is to find a sponsor to fund the next steps in developing a product. Because the Lactobacillus preparation is intended for underdeveloped countries, it is unlikely that a pharmaceutical company will be interested in investing in a product that is unlikely to earn a profit, Tao said.

But if this approach works, freeze-dried Lactobacillus has the potential to prevent half a million HIV infections annually, he added.

Study: Mouth Bacteria May Defend Against AIDS Virus

Two strains of Lactobacillus bacteria can hook onto HIV and stop it from getting into cells. The bacteria also cause immune cells to clump, which could be used to stop HIV-infected cells from infecting other cells, the researchers told a meeting of the American Society for Microbiology in New Orleans.

"While studies have been done so far only in the laboratory, we believe this work opens up new possibilities for preventing the transmission of HIV through mothers' milk," said Lin Tao, associate professor of oral biology in the University of Illinois at Chicago's College of Dentistry.

"Unlike standard retroviral drugs, which are too toxic for newborns, lactobacilli are 'friendly' bacteria already inhabiting the human digestive tract and milk products, and so should pose no danger to infants."

The AIDS virus affects an estimated 43 million people worldwide and has killed more than 25 million. It is passed through body fluids like blood, semen and mother's milk.

Many babies born free of HIV are infected by breast feeding -- an estimated 25 percent in some areas. Up to 800,000 babies are infected each year globally.

Giving the mother and baby antiretroviral drugs, especially one called nevirapine, can protect the infants at birth, but they risk becoming infected later if they are breastfed.

"This discovery opens up a possible means of preventing the transmission of HIV from mother to infant through breast feeding," Tao, who led the study, said in a statement.

Tao's team studied bacteria taken from volunteers.

"The two strains were found to bind with several varieties of HIV, the related simian immunodeficiency virus, and immune cells that HIV targets for infection," Tao said. "Further analysis showed that the bacteria inhibited HIV infection of immune cells in the laboratory."

© Reuters 2004. All Rights Reserved.

Study Says Condoms Contain Cancer-Causing Substance

The Chemical and Veterinary Investigation Institute in Stuttgart, Germany, said it found the carcinogen N-Nitrosamine present in 29 of 32 types of condoms it tested in simulated conditions.

"N-Nitrosamine is one of the most carcinogenic substances," the study's authors said. "There is a pressing need for manufacturers to tackle this problem."

The carcinogen is thought to be present in a substance used to improve condom elasticity. When the rubber material comes in contact with human bodily fluids, it can release traces of N-Nitrosamine, the study said.

Local government officials said condom users should not stop using rubber contraceptives based on results of the study because N-Nitrosamine does not present an immediate health danger.

But Germany's Federal Institute for Risk Assessment said that daily condom use exposed users to N-Nitrosamine levels up to three times higher than levels naturally present in food.

© Reuters 2004. All Rights Reserved.

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