Glossary

mutation – a change in the genetic structure of an organism (including a virus like HIV). See resistance.

Changing treatment and drug resistance.

phenotype — relating to how an organism behaves, based on how its genotype relates to the environment. Phenotypic resistance tests look at whether HIV continues to grow in a test tube after increasing concentrations of a drug are added. See genotype.

BMI (body mass index) – a calculation using  height and weight that is used to decide whether someone is over or under weight.

Online BMI calculator.

compensatory mutation – this refer to an additional mutation, usually in the context of the fitness of a virus. For example, the mutations that stop a drug form working often stop the virus from reproducing as well. Additional mutations that return the virus to it’s former fitness are called compensatory mutations. They compensate for the reduced viral fitness. See revertant mutation.

Intermediate level resistance – when a drug still has some impact on HIV, but when this is reduced (compared to wild-type HIV) because there is some drug resistance.