What is the meaning of ‘index case’?

The index case is the initial case of HIV infection in a person newly diagnosed with HIV.  The health professional must raise with this person the possibility of notifying his or her partners of the need to test and potentially treat.  Partner notification is completely dependent on the index person being prepared to discuss the matter and to identify partners who need follow-up.  If the index person chooses not to provide any information or details about the partners at risk, then there is no possibility for a health professional to contact those partners. Therefore, in order to have this discussion with an index person, it is important that the health professional create a non-threatening and non-judgmental environment in which the index person is comfortable to talk.  The interview should be confidential and private and the language used must be easily understood by the index person.

It is important to determine with the index person what kinds of sexual activities took place and, therefore, which of those activities could potentially transmit HIV. By having this discussion, the health professional can also identify sexual activities that do not need to be followed up, such as those where the risk of transmission was nil.  In addition, It is important to have an understanding of infection prodromes and window periods as this will determine how far back in time partners should be contacted.  For example, when considering partners of a person diagnosed with HIV, there is no need to contact partners where the sexual activity was protected (such as with a condom) or partners who were identified where the sexual activity took place over 3 months prior to the last negative HIV test result of the index person.

It is important to stress to the index person that if a health professional is to notify partners on his or her behalf, then the identity of the index person will remain strictly confidential and will never be divulged to the partner.  If this is not guaranteed, then the index person is often anxious and will not provide the health professional with the contact details of all partners who are at risk.

If the index person does not feel safe enough to provide information, or lacks the confidence to follow up the partners themselves, then partner notification by the index person is not possible.  The index person is more likely to provide information to a health professional or carry out partner notification themselves if they understand why it is important to notify partners and what the potential outcome for partners will be.