Biopharmaceutical Solutions

Background information

• What is HIV?
  HIV is a retrovirus that causes acquired immunodeficiency syndrome (AIDS), a syndrome characterized by progressive deterioration of the immune system. HIV/AIDS patients are at risk for opportunistic infections because of their diminished immune function, which may eventually lead to their death. 
• Global burden
  At the end of 2007, it was estimated that 33.2 million people worldwide were infected with HIV. There were approximately 2.1 million AIDS deaths, and another 2.5 million people were newly infected with HIV. Young people between the ages of 15 and 24 now account for almost half of all the new infections. Young women are especially vulnerable, with prevalence rates being as high as four times those for young men of the same age.
• Geographic distribution
  HIV/AIDS is a worldwide pandemic. Nearly two-thirds of those living with HIV/AIDS are located in sub-Saharan Africa. Southern Africa has been hardest hit; in several countries, the prevalence of HIV exceeds 30 percent of the adult population. Although the prevalence of HIV in South and Southeast Asia is much lower than in Africa, its huge population makes it second to Africa in terms of the total number of individuals infected.
• Causative agent/transmission
  HIV is spread by exposure to infected body fluids including blood, semen, and breast milk. The major routes of transmission are by sexual contact, through contaminated needles, and from infected mother to child in utero, at birth, or through breastfeeding. HIV mutates rapidly, and today patients are infected by many different strains. Most broadly, HIV can be classified as HIV-1 or HIV-2. HIV-1 is more virulent than HIV-2, causes the majority of infections, and can be divided into several distinct groups, which are themselves divided into subtypes, or clades, that display distinct geographic infection patterns. Treatment is more complicated in regions where more than one clade is circulating because hybrid strains can arise.

Presentation

Clinical diagnosis of HIV infection is complicated by the lack of specific symptoms. Two to four weeks after infection, patients may display flu-like symptoms accompanied by a rash and fever. However, many patients are initially asymptomatic. Although the incubation period between infection and onset of AIDS is often cited as seven to 10 years, disease course is accelerated in low- and middle-income countries due to environmental factors including burden of disease and nutrition. Once a patient develops AIDS (as defined as a CD4 lymphocyte count of <200 cells/µL), the disease is characterized by decreased immune functioning and an extreme susceptibility to opportunistic infections.

Trends

The HIV/AIDS epidemic has spread rapidly and is now considered a global pandemic. More than 95 percent of all new infections occur in people living in low- and middle-income countries. There is some good news—since 2000, worldwide, the percentage of people living with HIV/AIDS has stabilized. Due to the success of antiretroviral (ARV) treatment programs in prolonging life combined with new infections, however, the total number of individuals infected with HIV continues to rise. Resistance to ARVs is common and transmission of HIV strains resistant to one or multiple drugs has been documented and appears to be increasing.

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