Discordance: experts study prevention of infection
Jan 25, 2009
A clinical trial on preventing the spread of HIV among discordant couples (where one person is HIV-positive and the other is negative) is going on. The Pre-Exposure Prophylaxis (PrEp) strategy involves administering a pill to an HIV-negative partner in a
A clinical trial on preventing the spread of HIV among discordant couples (where one person is HIV-positive and the other is negative) is going on. The Pre-Exposure Prophylaxis (PrEp) strategy involves administering a pill to an HIV-negative partner in a relationship to prevent them from contracting the virus. The Infectious Disease Institute is conducting the study. Elvis Basudde interviewed Dr. Edith Nakku, the coordinator of the study
Question: What is PrEp about? Answer: There is scientific evidence that Tenofovir (Viread) and the combination of Tenofovir plus Emitricitabine (Truvade), if taken daily as preventive therapy, might substantially reduce the risk of contracting HIV.
This approach is known as pre-exposure prophylaxis (PrEp). Pre means before exposure to contact with HIV and Prophylaxis is about taking medication to prevent infection.
Why conduct the study?
A safe and effective approach to preventing new HIV infections is needed urgently. Each day, nearly 11,000 peopleworldwide get infected with the virus. Most of them live in Africa.
The traditional prevention methods include abstinence, being faithful to one’s sexual partner, and using condoms. However, not everyone is able to use these methods. The majority of HIV infections in Africa occur among women.
The current prevention methods are inadequate, since women often do not have social or economic power to refuse sex or negotiate condom use. A vaccine against HIV is most likely to be availed in 10 years’ time, so a new prevention strategy must be found.
How might PrEp protect against HIV infection?
The idea of medication that prevents infection is old. For instance, mothers who are living with HIV take medication during pregnancy to prevent them from passing the virus on to their unborn babies.
This is key because the medication gets into the bloodstream before one is exposed to infection. It also helps to prevent infection from occurring. If the PrEp medication is already in the bloodstream, when one is exposed to the virus, it would not be able to establish itself, so infection would not occur.
Is PrEp different from ARVs?
A person who is HIV-negative takes PrEp medication to prevent them from contracting HIV, whereas ARVs are given to people living with the virus, to decrease the amount of virus.
What studies on PrEp are being done?
Seven studies are being carried out in Africa, Asia, South America and the US. They will involve more than 15,000 participants, who will have to be in stable relationships or married.
How does discordance occur?
Studies in Africa have found that the partner of an HIV-infected person has a 50% chance of being infected, even if the couple has been together for several years. The factors include higher HIV levels, genital herpes and the male partner being uncircumcised.
Many couples have been in relationships for years and may not know each other’s HIV status. In spite of this, however, the uninfected partner in a discordant relationship can still become infected.
In fact, stable couples that are HIV discordant are thought to account for the majority of new HIV infections among adults in Africa.
How is the PrEp study designed?
It will include about 3,900 discordant couples, enrolled at eight clinical sites in Uganda and Kenya. The study is random and the participants, who are HIV-positive, will be randomly divided into groups. All participants will take their medication everyday. One group will take tenofovir; the second, a combination of emtricitabine and tenofovir; and the third will take a placebo.
What is a placebo?
It is an inactive pill that has no medicine in it that looks or tastes like tenofovir or emtracitibine. In research studies, the medicine being tested is compared with a placebo to see if the effects are truly due to the medication or merely chance.
The placebo is necessary because there is no evidence that PrEp can prevent HIV infection, so there is need to study the number of participants who get infected with HIV during the study.
Who can take part?
The study will enroll voluntary HIV discordant couples who are sexually active. To protect the health of the participants, both the HIV-negative and positive partners must meet the eligibility requirements.
The uninfected partner must be healthy, with a normal liver, kidney and blood count tests and cannot take medication that might interfere with the medication.
The uninfected partner should not be pregnant or breastfeeding.
The infected partner must also be in good health, having a CD4 count of over 250 cells and ineligible for treatment with HIV. Participants will be studied for about three years.
What happens if a participant becomes pregnant?
Tenofovir and emtricitabine/tenofovir have been used safely by HIV-infected pregnant women, and animal studies have shown that these medications do not harm the unborn baby.
However, there is little experience with these drugs to tell if they are safe for pregnant women.
As a result, family planning services will be provided for all participants. Women taking the trial medication will have pregnancy tests at every monthly visit, so that pregnancy can be detected early.
If a woman taking study tablets becomes pregnant, the study medication will be stopped, but she will still continue taking part.
Question: What is PrEp about? Answer: There is scientific evidence that Tenofovir (Viread) and the combination of Tenofovir plus Emitricitabine (Truvade), if taken daily as preventive therapy, might substantially reduce the risk of contracting HIV.
This approach is known as pre-exposure prophylaxis (PrEp). Pre means before exposure to contact with HIV and Prophylaxis is about taking medication to prevent infection.
Why conduct the study?
A safe and effective approach to preventing new HIV infections is needed urgently. Each day, nearly 11,000 peopleworldwide get infected with the virus. Most of them live in Africa.
The traditional prevention methods include abstinence, being faithful to one’s sexual partner, and using condoms. However, not everyone is able to use these methods. The majority of HIV infections in Africa occur among women.
The current prevention methods are inadequate, since women often do not have social or economic power to refuse sex or negotiate condom use. A vaccine against HIV is most likely to be availed in 10 years’ time, so a new prevention strategy must be found.
How might PrEp protect against HIV infection?
The idea of medication that prevents infection is old. For instance, mothers who are living with HIV take medication during pregnancy to prevent them from passing the virus on to their unborn babies.
This is key because the medication gets into the bloodstream before one is exposed to infection. It also helps to prevent infection from occurring. If the PrEp medication is already in the bloodstream, when one is exposed to the virus, it would not be able to establish itself, so infection would not occur.
Is PrEp different from ARVs?
A person who is HIV-negative takes PrEp medication to prevent them from contracting HIV, whereas ARVs are given to people living with the virus, to decrease the amount of virus.
What studies on PrEp are being done?
Seven studies are being carried out in Africa, Asia, South America and the US. They will involve more than 15,000 participants, who will have to be in stable relationships or married.
How does discordance occur?
Studies in Africa have found that the partner of an HIV-infected person has a 50% chance of being infected, even if the couple has been together for several years. The factors include higher HIV levels, genital herpes and the male partner being uncircumcised.
Many couples have been in relationships for years and may not know each other’s HIV status. In spite of this, however, the uninfected partner in a discordant relationship can still become infected.
In fact, stable couples that are HIV discordant are thought to account for the majority of new HIV infections among adults in Africa.
How is the PrEp study designed?
It will include about 3,900 discordant couples, enrolled at eight clinical sites in Uganda and Kenya. The study is random and the participants, who are HIV-positive, will be randomly divided into groups. All participants will take their medication everyday. One group will take tenofovir; the second, a combination of emtricitabine and tenofovir; and the third will take a placebo.
What is a placebo?
It is an inactive pill that has no medicine in it that looks or tastes like tenofovir or emtracitibine. In research studies, the medicine being tested is compared with a placebo to see if the effects are truly due to the medication or merely chance.
The placebo is necessary because there is no evidence that PrEp can prevent HIV infection, so there is need to study the number of participants who get infected with HIV during the study.
Who can take part?
The study will enroll voluntary HIV discordant couples who are sexually active. To protect the health of the participants, both the HIV-negative and positive partners must meet the eligibility requirements.
The uninfected partner must be healthy, with a normal liver, kidney and blood count tests and cannot take medication that might interfere with the medication.
The uninfected partner should not be pregnant or breastfeeding.
The infected partner must also be in good health, having a CD4 count of over 250 cells and ineligible for treatment with HIV. Participants will be studied for about three years.
What happens if a participant becomes pregnant?
Tenofovir and emtricitabine/tenofovir have been used safely by HIV-infected pregnant women, and animal studies have shown that these medications do not harm the unborn baby.
However, there is little experience with these drugs to tell if they are safe for pregnant women.
As a result, family planning services will be provided for all participants. Women taking the trial medication will have pregnancy tests at every monthly visit, so that pregnancy can be detected early.
If a woman taking study tablets becomes pregnant, the study medication will be stopped, but she will still continue taking part.