Selected words and phrases

diagnosis – identifying the cause of an illness.

axis – line on a graph to measure data. Graphs usually have a vertical axis (y-axis) and horizontal axis (x-axis). An axis should show what is being measured and the units of measurement, eg ‘time (in minutes)’.

primary mutation – see major mutation.

IRIS (immune reconstitution inflammatory syndrome) – illnesses that occur when HIV treatment is started when the CD4 count is very low.

IRIS occurs because the immune system quickly becomes stronger and identifies infections that it was previously too weak to fight.

IRIS can occur in 1 in 4 (25%) people who start with a CD4 count under 50 cells/mm3.

Although the symtoms are serious, IRIS can usually be easily managed.

Common infections related to IRIS include TB and CMV.

On-demand dosing – a term for taking medicines only at times linked to a relevant event.

On-demand dosing for PrEP is also called “event based dosing” (EBD).

For example, on-demand dosing for PrEP (to prevent HIV transmission) involves taking PrEP before sex and then for several days after sex. EBD for PrEP is only appropriate in some situations and for some people – otherwise daily dosing is recommended,