News (Updated January 30, 2005)
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Thursday January 27, 8:26 PM
A recent rise in syphilis rates in the United States is probably due to natural cycles rather than an increase in unsafe sex or other behaviors, according to a new study.
The finding is encouraging to public health authorities who have worried that increasing syphilis infection, especially among gay and bisexual men, is a sign that people at high risk for HIV have grown complacent about practicing safe sex.
Syphilis has been on the rise in the United States since 2000, when the incidence of the disease was at its lowest in six decades. In 2003, the most recent year for which data are available, 7,177 cases were reported, compared with 5,979 in 2000.
"One would expect for the next few years for syphilis incidence to continue to rise," said Nicholas C. Grassly, one of the study's authors.
Similar jumps in syphilis incidence have been observed in the past. When syphilis rates peaked in the early 1970s, some researchers blamed the sexual revolution; when infections rose again a decade later, they were attributed to the spread of crack cocaine.
Grassly and his colleagues argue in this week's issue of the journal Nature that syphilis infection follows a natural cycle that peaks at eight- to 11-year intervals. Though sexual behavior certainly influences the overall number of people infected, the researchers concluded, those regular ups and downs are an intrinsic property of the disease itself.
The researchers discovered the oscillating pattern by examining syphilis infection trends in 68 U.S. cities over the past 50 years. But when they looked at the pattern of gonorrhea infection over the same period, the pattern was absent. Gonorrhea rates tended to rise over the second half of the 20th century, then fell gradually beginning around 1980.
Because the diseases spread the same way, if changes in sexual behavior had caused the oscillating pattern in syphilis they should have created a similar pattern in gonorrhea. Yet gonorrhea rates show a steady rise from the 1950s through the 1970s, followed by a steady fall.
"You don't see these repeated, regular epidemics," said Grassly, an epidemiologist at Imperial College in London. He wrote the Nature paper with Christophe Fraser and Geoffrey P. Garnett, also of Imperial College.
The key to the difference between syphilis and gonorrhea is immunity. Unlike those who catch gonorrhea, people who recover from syphilis can resist re-infection for some time afterward. That means when the disease sweeps through a city, it leaves a relatively immune population in its wake and infection rates fall.
But as the population gradually evolves, the proportion of susceptible individuals rises and so do infection rates. Using a computer model, Grassly and his colleagues showed that the time from one peak to the next should be about a decade.
"It's a kind of neat piece of detective work," said Bryan Grenfell, a biologist at Pennsylvania State University who studies childhood infectious diseases. Many of those illnesses, such as measles and chickenpox, also follow oscillating patterns.
The British researchers detected another interesting pattern in the data as well. Until about 1980, syphilis rates in different cities varied independently. Houston might be experiencing a peak at the same time that New York was going through a trough. But more recently, syphilis rates have become much more uniform in the United States.
Thu Jan 27, 2005 12:01 AM ET
LONDON (Reuters) - Americans, and especially women, are three times more likely
to suffer premature death and adverse health due to sexual activity than people
in other rich nations, scientists said on Thursday.
Researchers from the U.S. Centers for Disease Control (CDC) found some 20 million cases of adverse health conditions and 29,745 deaths in the United States in 1998 were related to sexually transmitted diseases.
"The research showed the sexual behavior attributable health burden is about three fold higher in the U.S. than other developed countries," Dr. Shahul Ebrahim, one of the authors of the CDC study, told Reuters.
"All of it is totally preventable and that's the message."
Ebrahim said the health burden included conditions such as infertility, abortions and infections such as gonorrhea.
Women accounted for 62 percent of all adverse health cases, with most female deaths attributable to cervical cancer and HIV.
Deaths from curable sexually transmitted diseases were, however, rare among both men and women.
The paper, published in the journal Sexually Transmitted Infections, was the first attempt to generate comprehensive findings on the health burden related to sexual behavior in the United States.
Tuesday January 25, 11:02 PM
A potential HIV/AIDS vaccine developed by Merck & Co. that uses synthetic genes to prepare cells to fight the deadly virus is moving into the second stage of testing.
An approved vaccine would be about a decade away if the trial and a third study are successful, said officials with the international coalition that is collaborating on the work.
"It is the most promising candidate that we've seen so far," said Sarah B. Alexander, associate director of the coalition, known as the HIV Vaccine Trials Network, or HVTN. She cautioned, however, "something better could come along tomorrow."
Volunteers began enrolling last month for the Phase II study, which will eventually give the potential vaccine's three doses to 1,500 people in North and South America, the Caribbean and Australia, the network and Whitehouse Station-based drug maker announced Monday.
The study is using male and female volunteers aged 18 to 45 of diverse racial groups who are at high risk for contracting HIV. Participants will receive counseling about how to reduce their risk of HIV infection, Alexander said.
About a dozen companies and organizations worldwide are attempting to develop an AIDS vaccine. Of the 10 associated with HVTN, the Merck candidate is the first to reach Phase II testing, Alexander said.
Of the two that reached Phase III, the final stage before certification is sought, one was deemed unsuccessful in 2000, and another, led by the U.S. Department of Defense, is enrolling volunteers, she said.
The Merck candidate _ the MRKAd5 HIV-1 gag/pol/nef, or trivalent, vaccine _ is designed to persuade the defenders of each cell, called "killer T cells," to attack HIV when the virus enters the cell. Other vaccines generate an antibody response.
The potential vaccine uses the virus of a common cold, modified so it cannot reproduce or cause people to catch a cold, to transport three synthetically produced HIV genes to the cells.
"We give the body enough of the virus so it can recognize it and create an immune response," but not enough to infect a person, Alexander said.
The Phase I study of the possible vaccine, involving about 1,000 people, "generated strong and durable cellular immune responses against HIV," Merck spokeswoman Janet Skidmore said.
Seattle-based HVTN is funded by the National Institute of Allergy and Infectious Diseases of the National Institutes of Health, an agency of the U.S. Department of Health and Human Services, and comprises more than 25 research institutions worldwide.
Merck shares fell 51 cents, or 1.7 percent, to close at $29.85 in Monday trading on the New York Stock Exchange. The stock, which has fallen sharply since Merck withdrew its Vioxx drug from the market amid safety concerns, has traded in a 52-week range of $25.60 to $49.33.
Wed Jan 26, 2005 04:31 PM ET
Amy Norton
NEW YORK (Reuters Health) - A sizable number of African Americans believe in various HIV conspiracy theories, and it may be deterring some men from using condoms, a new survey suggests.
Researchers found that among 500 African Americans ages 15 to 44, more than half believed that information about HIV/AIDS is being held back from the public, and that a cure for AIDS exists but is being "withheld from the poor."
In addition, nearly half agreed with the statement that "HIV is a man-made virus," while a much smaller percentage -- about 15 percent -- believed the AIDS epidemic is a form of genocide against blacks.
Among men, who tended to hold stronger conspiracy-theory views than women, such beliefs were linked to lower rates of condom use, according to findings published in the Journal of Acquired Immune Deficiency Syndromes.
"These beliefs are widespread and demonstrate substantial mistrust of the health care system among African Americans," lead study author Dr. Laura M. Bogart, a psychologist at the research organization RAND Corp., said in a statement.
"For HIV prevention efforts to be successful, these beliefs need to be discussed openly, because people who do not trust the health care system may be less likely to listen to public health messages."
A number of studies have demonstrated that black Americans have a greater distrust of doctors and medical researchers than whites do -- a discrepancy thought to stem from the history of racial discrimination in the U.S. health system.
Most infamous was the "Tuskegee study," a 40-year project that ended in the early 1970s, in which researchers withheld treatment from poor black men with syphilis in order to document the natural progression of the infection.
To win greater trust in black communities, Bogart and her colleagues write in the report, public health agencies "need to acknowledge the origin of conspiracy beliefs openly."
Enlisting the help of people in black communities to spread public health messages about HIV and conspiracy beliefs -- known as peer education -- could be one way to address the issue, according to the researchers.
The study, a telephone survey of a national sample of black Americans, asked respondents the extent to which they agreed or disagreed with a number of statements about HIV.
Overall, 58 percent "somewhat" or "strongly" agreed with the statement, "A lot of information about AIDS is being held back from the public." Fifty-three percent believed that there is a cure for AIDS, but it's being withheld from the poor.
Few respondents agreed with the most extreme conspiracy theories -- including the notion that doctors "put HIV into condoms" or that HIV/AIDS drugs are "poison."
SOURCE: Journal of Acquired Immune Deficiency Syndromes, February 1, 2005.