Q&A: Expert's Answers to Frequently Asked Questions About AIDS
Following is an interview with Dr. Peter Drotman, a medical epidemiologist in the aids program at the federal Centers for Disease Control. In its role as the federal government's chief disease-prevention agency, the cdc has been in the forefront of research on acquired immune deficiency syndrome since the early 1980's.
Staff Writer Debra Viadero asked Dr. Drotman questions that administrators, teachers, and students frequently raise about the fatal disease.
QWe know that aids can be contracted through sexual intercourse with an infected partner, by using dirty needles, by transfusions of infected blood, and by perinatal transmission. How is the disease most effectively transmitted?
ARecipients of blood units that were infected and transfused into them before 1985 have the highest rates of infection of any group. So if you are comparing one instance of sexual intercourse versus one instance of sharing a drug needle with an infected person and one transfusion with a unit of infected blood, certainly the highest risk would be to the person having the transfusion. Fortunately, the risk in blood transfusions is now largely eliminated because all blood units are tested for the presence of the virus.
QMany teachers are advising their students to use condoms to protect against infection through sexual activity. How effective are condoms in providing such protection?
AThe evidence on condoms and aids is largely laboratory evidence. And in the laboratory, condoms perform very well. Latex condoms are the ones that have mainly been tested, and they are impervious to the virus.
The major obstacles to the effectiveness of condoms are behavioral. They can only work if people use them properly and consistently. Used properly, condoms are very effective--not 100 percent effective--in preventing both pregnancy and a number of sexually transmitted dis4eases, including infection with the aids virus.
QDoes the use of spermicide along with a condom increase the condom's effectiveness?
AIt does in the laboratory. The spermicides, particularly those that contain nonoxynol-9--as most of the common spermicides in the pharmacy do--will kill the aids virus rapidly and efficiently in the laboratory. So we recommend that a spermicide be used in addition to condoms, though certainly not in place of them.
QDon't some lubricants that may be used in intercourse reduce the effectiveness of condoms?
APetroleum-based lubricants can weaken the structure of latex condoms, so that type of lubricant is usually advised against.
QOne question teen-agers often ask is, "What is the likelihood of contracting the disease through open-mouthed or 'French' kissing?"
AThat's not a question that can be answered with certainty, because there are no known cases of aids or instances of aids-virus transmission that are attributable to open-mouthed kissing or other exposure to saliva.
Clearly, French kissing does not present a great threat. The evidence that suggests transmission through such activity might be possible, however, is that a small minority of aids patients--maybe 1 out of 18 or 20--have detectable amounts of aids virus in their saliva.
QWould such kissing be riskier if there were open sores in the mouth?
ANo. There are some people who have been exposed to saliva who have had open sores. Those people haven't become infected.
QTeachers tell me that students also ask if they can get the disease from mosquitoes.8What is the possibility of transmission by mosquitoes, head lice, ticks, or other insects?
AThere is no transmission of the aids virus through any insect. Usually when diseases are transmitted by such carriers it's because the life cycle of the parasite requires passing through the insect. That is clearly not the case for the aids virus. The virus does not reproduce itself inside insects.
The other theoretical possibility would be mechanical transmission by insects. But there is too little of the virus in an infected person for it to be ingested by a mosquito and survive long enough to be injected into the next person bitten.
The possibility of insect transmission has been evaluated in a number of places around the world, including Africa and Florida, and there is no evidence for it.
QTattoos are popular among young people in some parts of the country. What is the risk of contracting the disease through tattoo needles?
AThat would depend on several factors: how diligent the tattoo artist is in maintaining and sterilizing his equipment, particularly the needle; whether he disposes of the needle after use; and whether previous customers were infected with the virus.
Certainly it's theoretically possible to transmit the virus through tattoo needles, though I don't know of any such cases.
QWhat risks do teachers run in cleaning up vomit and other fluids of a child with aids?
AThere are no known instances of the aids virus having been transmitted in school through cleanup or hygiene activity.
Similarly, there are no instances of transmission in the homes of children with aids. We have studied many people in the United States who have taken care of aids patients in their homes, and that care includes cleaning up after them and giving them baths, as well as using the same showers and toilets and kitchens and laundry. None of theel10lcare providers has become infected. If there is a risk, it's too small for us to measure.
QSome school districts are passing out plastic gloves to teachers and coaches who might come into contact with students' bodily fluids. Is this a necessary precaution?
AI don't know if it's necessary or not. We do recommend that people who work in laboratories or hospitals have access to gloves and other safety equipment when they are doing work that entails exposure to blood. Whether that's something that is appropriate for schools is for the schools to decide. For most normal school activities, gloves would certainly not be called for.
QHow prevalent is the virus in urine?
AI have never seen a scientific report on the isolation of the aids virus from urine, but I can't say that it could never be present.
QAre there any documented cases of a child with aids having passed the disease to a playmate or a sibling?
QWasn't there an instance in Germany in which one brother passed the disease to another?
AIn a letter to a British journal, German physicians reported aids-virus infections in two brothers, but it's not entirely clear how those brothers got infected.
QWe read several months ago about health workers who became infected with the virus when they came into contact with contaminated blood. One of them had acne. What are the risks of being exposed to the virus through skin that is inflamed but not broken?
AWe disclosed those cases last May because they are extraordinary. They are the only three such cases ever reported to us. And4the thing that links them is that they all represent occupational exposure to blood on non-intact skin or mucous membrane--a lining of the mouth.
That may indicate that having less than perfectly healthy skin may increase the permeability of the skin to infection. But that's not proven by any means, and I'm sure there are many thousands of health-care workers and others who have had infected blood splashed on their skin and do not appear to have become infected.
QWhat role does geography play in increasing one's risk of contracting the disease?
APeople who are infected with the virus are very much concentrated in big cities, particularly on the East and West coasts. People who live in big cities are certainly at higher risk than those who live in the country.
But in the spread of diseases over time, the tendency is for geographic distinctions to become more and more blurred. In fact, aids cases have been reported in all 50 states, the District of Columbia, Puerto Rico, and the other territories of the United States.
QHow serious is the threat that the disease will become prevalent in the teen-age population?
AThe virus that causes aids is transmitted from one person to another through particular behaviors--sexual and drug-using behaviors--that frequently are adopted in one's teen-age years.
Teen-agers are an important group to talk to in preventing this infection from taking hold. And it's certainly not too late, because few teen-agers have been diagnosed as having the disease. Likewise, I think, not many have been infected with the aids virus, although we don't know for sure.
But we do know that the risk seems to increase as one gets older--into the 20's and 30's. So it's best when one is a teen-ager to adopt a safe lifestyle with healthful habits and to maintain them. Then you don't have to worry about aids.