Since both HIV and HCV are potentially life-threatening conditions, one of the main benefits from averting infections is the prevention of premature mortality. However, there are considerable contrasts in the natural history of these two chronic viral infections, particularly in the rate of progression to advanced disease and related complications.

Prior to the introduction of improved antiretroviral therapy in the mid-1990s, a half of people with HIV would have developed advanced immunodeficiency and associated AIDS illness complications during the first 10 years of infection. Although a small proportion of people – possibly 5% – were considered long-term non-progressors the majority of the other half would have had evidence of immune function deterioration, and were at risk of progression to AIDS in subsequent years. Survival following development of AIDS was approximately 18 months. Thus, it was expected that very few people with HIV would have been alive or free of AIDS after 15-20 years infection. Although several pre-AIDS HIV conditions are associated with considerable morbidity, the major morbidity associated with HIV infection was as a result of the development of specific AIDS illnesses.

Since the introduction of highly active antiretroviral therapy (HAART), HIV disease progression has markedly slowed, both for people prior to and following development of AIDS illnesses. Morbidity and mortality associated with AIDS illnesses have declined by 50-80% in settings where access to HAART is widespread. On the other hand, there has been an increase in morbidity associated with side effects of therapy. This effect, however, is relatively modest when compared with prior AIDS illness-related morbidity. The sustainability of the effect of HAART on immune function, and longer-term therapeutic toxicity are two areas where there is some uncertainty regarding levels of morbidity and mortality that will be experienced by people with HIV in the next decade.

The natural history of HCV infection varies with HIV in many areas. First, a proportion of people – possibly 20-40% – do not develop chronic infection and are therefore not at risk of advanced liver disease complications. Second, progression to advanced disease is both slower than HIV and not inevitable. An estimated 20% of people with chronic hepatitis C will develop cirrhosis over 15-40 years and be at risk of liver failure and liver cancer. Although the remaining 80% will not develop morbidity associated with advanced liver disease complications, many people suffer considerable morbidity related to a range of relatively non-specific symptoms. These include chronic lethargy, abdominal discomfort, and headaches. There is also recent evidence that HCV may cause cognitive impairment including difficulties with concentration. Pre-advanced liver disease morbidity in chronic hepatitis C is unrelated to the extent of liver damage.
Top of page
As with HIV, antiviral therapy for HCV has improved in recent years. Currently, 50% of people with chronic hepatitis C who commence standard of care antiviral therapy (interferon and ribavirin combination) develop a sustained response that equates to a probable cure of their infection. Antiviral therapy therefore has the potential to considerably reduce morbidity and mortality related to chronic hepatitis C, however, for several reasons uptake to date has been relatively limited.

HIV and HCV may also have psychosocial effects among infected persons, some of which may be associated with discrimination and social stigma. These will also impact on the person's quality of life, regardless of whether the disease progresses or not.

Given the above, it is likely that gains in quality of life are one of the major health benefits of the prevention of HIV and HCV infections.