Arms: the group in a clinical trial, usually known as the control
group and intervention group. Comparing results from the different
groups enables researchers to determine whether and how well a new
intervention (treatment, vaccine, prevention method, or what ever
is being tested) works. Some studies are designed to test more than
one treatment; these would have more than two arms/group.
Cellulose sulfate (CS) – a gel that was tested as a possible topical
microbicide but in 2007 was found not to be effective. Researchers
thought that CS could potentially block HIV infection (and possibly
other STI infections) by creating a barrier between the virus and
the woman’s cells in the vagina, which the virus targets for
infection. This would make it more difficult for the virus to enter
the woman’s cells.
Cohort- a defined group of people who are followed over a period of
time during a trial to see if anything changes in their situation
(e.g. a group of HIV negative women could be treated as a cohort).
Coital act – sex involving the penetration of a penis into a vagina.
Control group- the comparison group in a clinical trial. This is the
group of trial participants who do NOT receive the intervention that
is being tested. Depending on the intervention being tested, they
usually either receive no treatment at all, a placebo, or current
treatment in use.
Diaphragm- a small latex silicone dome/cup that covers the cervix
(the lower part of the uterus, or womb, that connects to the
vagina). A diaphragm prevents pregnancy by covering the cervix and
blocking sperm from entering the uterus. It also blocks viruses and
bacteria from entering. Trails have shown that the diaphragms DO NOT prevent women from HIV infection.
Double blind- in a double-blind trial, neither the participants nor
the researchers know which participants are in the control group and
which are the intervention group. This is done to reduce bias
from both researchers and participants. An independent group of
experts who are not researchers in the trial, the Data Safety
Monitoring Board, look at the different points in the trial.
DSMB (Data Safety Monitoring Board)- an independent panel of experts who are not researchers associated with the clinical trial, but who have responsibility to look at the results at different points
during a trial to make sure that it is not ethically necessary
to stop the trial either because the intervention causes greater
risk or is overwhelmingly successful.
Efficacy versus Effectiveness- Efficacy refers to how well an
intervention works under controlled situations (such as in a trial).
Effectiveness refers to how well an intervention works in real life
settings.
Epithelium- layer of cells lining the vagina, the cervix, uterus(and
other body cavities).
Fusion inhibitor- a microbicide that would work by preventing HIV
from attaching to a woman’s cells.
Interim data analysis- conducted by the DSMB. Data from the control
and intervention groups of a trial are examined and analysed during
the trial at different points, not just at the end when all the
data is completely collected and the trial is finished. These
interim data analyses are used to make sure that the trial does not
need to be stopped early for safety reasons, or because the
intervention being tested is either causing harm or is shown to be
effective.
Intervention groups- the group of participants receiving the
intervention (e.g. new treatment, vaccine, prevention method) in a
clinical trial.
Microbicide- any compound or substance that can be used to reduce
the ability of a virus or bacteria to infect cells. The microbicide
candidates being developed and tested now for HIV prevention are all topical gels or creams that are inserted into the vagina (or anus),
and that coat the cells lining the reproductive tract.
Second and third generation microbicides- first generation
candidates were the first possible microbicides that were tested but
proven not effective. Second and third generation candidates are
those more recently developed that use and build on the results
obtained from the candidates that didn’t work, as well as the new
information and knowledge about HIV. Some of these more recent
microbicide candidates are ARV- based.
Mode of action- how a treatment works. There are several possible
modes of action for microbicides. Some acts as physical barriers,
blocking the virus from entering a woman’s cells, others prevent HIV
from entering and infecting the woman’s cells, while others
preventing the virus from making copies of it self.
N-9( (nonoxynol-9)- a spermicide (kills sperms to prevent pregnancy) that was tested as a microbicide to prevent HIV infection. It was NOT affective, and its regular use increase women’s risk of HIV infection. N-9 works as a surfactant, by breaking up the membrane (outer layer) of the virus, but its regular use also causes
irritation and lesions in the vagina, which made it easier for HIV
to enter the woman’s cells.
Oral prophylaxis- taking anti-retroviral pills, either before
sexual exposure (pre-exposure prophylaxis) or after sexual exposure (post-exposure prophylaxis) to HIV.
Pap test (also known as a pap smear)- a medical screening test,
where calls are taken from the cervix and looked at under a
microscope to see if there are any cells that look abnormal. The pap
smear is a way to screen women for early signs of cervical cancer.
Phase 3 clinical trials- randomized clinical/controlled trials on
large groups of participants to look at the efficacy of a new
intervention. Phase 3 trials are begun only after phase 1 and phase
2 trials (which are smaller studies that look at safety, at doses,
and at efficacy) are successfully completed.
Placebo- in a blind or double-blind clinical trial, the control
group receives a placebo. This is not the treatment being tested,
but it looks exactly like the treatment. For typical microbicide
trials, the control group received a gel that looked and was used
the same as the gel given to the intervention group, except that it
did not contain the microbicide. Placebos are used in blinded
clinical trials so that participants and researchers do not know
which participants are in the control group and which are in the
intervention group.
Post- exposure prophylaxis (PEP)- taking oral anti-retroviral
medication for a short period of time after exposure (such as an
accidental needlestick for a health care worker), or possible
exposure to HIV (as in the case of rape). PEP should begin 2-24 hours after the exposure to HIV, and no later than 72 hours. There is evidence that PEP can lower tha risk of HIV infection after exposure.
Pre-exposure prophylaxis (PEP)- taking oral anti-retroviral
medication before HIV exposures. Currently, clinical trials are
being done to determine the efficacy and effectiveness of PEP for HIV prevention.
Randomized clinical/controlled trial- a study to determine whether
and how well a medical intervention (e.g. a drug treatment, a
vaccine, a prevention method, etc.) works. Usually, there are two
groups (also called arms), the control group and the intervention
group. The control group either gets no treatment, the current
standard treatment, or a placebo. The intervention group gets the new intervention. Results from both groups are compared to see whether and how well the intervention works. Participants are placed into the groups randomly (by chance, without knowing which groups they are placed in). There are stages of trials. The first stages test
with small numbers of participants to make sure the intervention is
safe. Later stages enroll more people ad test the intervention’s
efficacy.
Sero-conversion- becoming infected with HIV. In clinical trials,
this term is used to refer to people who were HIV negative when they
enrolled in the trial, who became infected during the trial.
STI- sexually transmitted infections.
Surfactant microbicide- a microbicide that works by disrupting or
breaking up the membrane (outer surface) of the HIV virus.
Target cells- type of cell that HIV, or another virus or bacteria,
infects.
Tenofavir – an antiretroviral (ARV) that is currently being tested
in gel format as a possible topical microbicide to prevent HIV
infection.
HIV vaccine- a vaccine that would prevent HIV infection. There is
no effective HIV vaccine at present, but there are several possible
vaccines being developed and tested.
Vaginal lesions- small scrapes of tear in the vaginal, which may be
cellular entry points from HIV.
Kingsley Obom-Egbulem, Delhi.
Nigeria-AIDS.org
February 28,2008
