EBD (event based dosing) – a term for taking medicines only at times linked to a relevant event.

EDD is also called “on-demand dosing”.

For example, EBD 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,

elite controller (EC) – an HIV positive person whose immune system keeps viral load undetectable for more than five years without ART.

Elite controllers also have a very good CD4 count (always above 500 cells/mm3) that stays at a similar level over many years.

Even with this good immune response, ART is still generally recommended in the long-term. This is because over decades – some ECs have been undetectable for more than 20 years – there is a concern that low level HIV in different body compartments like the brain, might lead to accumulative serious damage that isn’t easy to detect until it is too late.

This is a real concern, though evidence is limited because of the rarity of ECs.

See: long-term slow progresso (LTSP)/long-term non-progessor (LTNP).

empirical treatment – treating an illness based on its symptoms to see if it gets better.

encephalitis – inflammation of the brain.

encephalopathy – degenerative brain function or disease

entry inhibitor (EI) – class of anti-HIV drug.

Drug targets in the virus life cycle.

enzyme – a protein produced in the body that triggers or speeds up other chemical reactions.

epoetin-alpha (EPO) – a treatment for anaemia, given by injection. Used to reduce side effect of hepatitis C treatment.

escape mutation – a mutation or change in the genetic structure of HIV that makes it easier to evade the persons immune system (rather than a mutation that stops an HIV drug from working).

ETR (end of treatment response) – having an undetectable HCV viral load at the end of HCV treatment. See SVR.

European Medicines Agency (EMA) – the EMA is the part of the European Union that is responsible for approving and regulating human and animal medicines and medical products.

See: www.ema.europa.eu/en

even distribution – where most results are in the middle and a roughly similar number of results fall either side. Also called bell-shaped or ‘normal’ distribution.

event-based dosing –  See EBD.

EVR (early virological response) – a 99% (2-log ) drop in HCV viral load after 12 weeks of HCV treatment.

expanded access programme (EAP) – a scheme that allows people to access a drug before it has been approved (but when approval is expected).

EAPs are for people urgently need treatment as a life-saving option and who do o have the time to wait for the six months that it takes for approval to be finalised. EAPs are usually available for most HIV drugs after the main studies (phase 3) have been completed.

They were an important early result of community activism. They are also called ‘early access’ or ‘named-patient’ programmes.