Glossary

Method of birth where the child is delivered through a cut made in the womb.

A disease caused by the fungi of the candida family such as Candida albicans. Commonly known as thrush.

In discussions of consent for medical treatment, the ability of a person to make a decision for themselves and understand its implications. Young children, people who are unconscious and some people with mental health problems may lack capacity.

A malignant tumour that may spread throughout the body.

Relating to the heart and blood vessels.

Disease of the heart or blood vessels, such as heart attack and stroke.

Describes the medical history of a single patient.

An observational study in which a group of people with an infection or condition (called ‘cases’) are compared with a group of people without the infection or condition (called ‘controls’). The past events and behaviour of the two groups are compared. Case-control studies can help us understand the risk factors for having an infection or a condition. However it is difficult both to accurately collect information about past events and to eliminate bias from case-control studies - see ‘confounding’.

Computerised axial tomography scan. A type of specialised X-ray that gives a view of a 'slice' through the body, and is used to help detect tumours, infections and other changes in anatomy.

A tube that is implanted with one end within the body and the other remaining outside, to make it easier to get drugs into, or waste products out of the body.

A molecule on the surface of some cells onto which HIV can bind. The CD4 cell count roughly reflects the state of the immune system.

A molecule on the surface of some white blood cells. Some of these cells can kill other cells that are infected with foreign organisms.

The brain and spinal cord.

Involving the brain.

The liquid surrounding the brain and spinal cord.

Involving the brain and the blood vessels supplying it.

This means changes to the cervical tissue which can be seen on visual examination through a colposcope. These are graded CIN1 to 3 according to whether one-third, two-thirds or all of the normal cells within the affected area are replaced by pre-cancerous ones. CIN1 is often left untreated; higher-grade lesions will probably need removing.

The neck of the womb, a tight ‘collar’ of tissue that closes off the womb except during childbirth. Cancerous changes are most likely in the transformation zone where the vaginal epithelium (lining) and the lining of the womb meet.

The use of drugs to treat an illness, often denotes drugs used to treat cancer.

A statistical test used when comparing two proportions (e.g. percentages with viral load below 50 copies/ml)

A waxy substance, mostly made by the body and used to produce steroid hormones. High levels can be associated with atherosclerosis.

When somebody has had an infection for at least six months. See also ‘acute infection’.

Scarring of the liver – the structure of the liver is altered. See also ‘fibrosis’, which is moderate scarring. See also ‘compensated cirrhosis’ and ‘decompensated cirrhosis’.

A term referring to the nursing or medical care of patients.

The occurrence of a physical sign or symptom, rather than an abnormality that can only be detected by laboratory tests.

A research study involving participants, usually to find out how well a new drug or treatment works in people and how safe it is.

A medical doctor who is active in looking after patients.

Central nervous system.

A position within a gene.

An observational study in which a group of people (called a cohort) is followed over a period of time and their medical history recorded. Cohort studies can help us understand the risk factors for having an infection or a condition. Prospective cohort studies (which track participants forward in time) are more reliable than retrospective cohort studies. However it is difficult to eliminate bias from cohort studies - see ‘confounding’.

Having more than one infection at the same time. For example, when a person with HIV has hepatitis B or C. This can make disease worse and treatment more difficult.

Inflammation of the bowels.

Examination of the large bowel using a video camera device.

Examination of the surface of the cervix under magnification to identify the location and extent of abnormal lesions.

Using more than one drug at a time.

The release of an experimental drug by its manufacturer to people who are unable to obtain it in a clinical trial.

The earlier stage of cirrhosis, during which the liver is damaged but still able to perform most of its functions. See also ‘cirrhosis’ and ‘decompensated cirrhosis’.

Hepatitis C RNA viral load is undetectable by week 12 of treatment. See also ‘partial early virological response (pEVR)’.

An alternative term for adherence.

An endpoint in a trial that includes several component parts; an individual is deemed to have met the criteria for the composite endpoint as soon as they meet the criteria for at least one of the components.

The level of a drug in the blood or other body fluid or tissue.

A range of values that gives us an indication of how precise an estimate is - if the confidence interval is wide, the estimate is imprecise. The ‘true’ result could be as low or as high as the lower and upper values that are given. A 95% confidence interval suggests that there is a 95% probability that the true result is within the range given. Confidence intervals give similar information to p-values but are easier to interpret.

Confounding exists if the true association between one factor (Factor A) and an outcome is obscured because there is a second factor (Factor B) which is associated with both Factor A and the outcome. Confounding is often a problem in observational studies when the characteristics of people in one group differ from the characteristics of people in another group. When confounding factors are known they can be measured and controlled for (see ‘multivariable analysis’), but some confounding factors are likely to be unknown or unmeasured. This can lead to biased results. Confounding is not usually a problem in randomised controlled trials.  

A patient’s agreement to take a test or a treatment. In medical ethics, an adult who has mental capacity always has the right to refuse. See also ‘capacity’ and ‘informed consent’.

An infection that can be spread easily, by casual contact.

An endpoint in a trial that captures a measurement which can have any value in a range, e.g. CD4 count.

A reason why a drug should not be used.

A group of participants in a trial who receive standard treatment rather than the experimental treatment which is being tested.

Occurs when the walls of the coronary arteries become narrowed by a gradual fatty build-up. Heart attack and angina are main symptoms.

Cost-effectiveness analyses compare the financial cost of providing health interventions with their health benefit in order to assess whether interventions provide value for money. As well as the cost of providing medical care now, analyses may take into account savings on future health spending (because a person’s health has improved) and the economic contribution a healthy person could make to society.

An enzyme (a protein that speeds up a chemical reaction) found mainly in the heart, brain, and skeletal muscle. Raised levels can indicate there has been muscle damage.

The mechanism by which a virus that has developed resistance to one drug may also be resistant to other, similar drugs.

A clinical trial where participants are switched from one arm to the other part way through.

A ‘snapshot’ study in which information is collected on people at one point in time. See also ‘longitudinal’. 

Increased blood levels of a protein that can cause inflamed blood vessels and thicken blood.

A type of fungal infection usually affecting the membrane around the brain, causing meningitis. It can also affect the lungs and chest.

Infection with the gut parasite Cryptosporidium parvum and other species, causing severe diarrhoea.

Laboratory medium in which microbes can grow.

When the virus is no longer present in the body. For hepatitis C, see ‘sustained virological response’.

Chemical "messengers" exchanged between immune cells that affect the function of the immune system. Interleukins such as IL-2 are a particular type of cytokine.

Harmful to cells.

A type of white blood cell which kills virus-infected cells.