If HIV is left untreated, it can have severe long-term effects on the body. Over time, the virus gradually weakens the immune system, leading to a significant drop in CD4 cells. This decline in immune function makes the body increasingly vulnerable to opportunistic infections and certain cancers. Common complications include infections like tuberculosis, pneumocystis pneumonia, and severe fungal infections, as well as cancers such as Kaposi's sarcoma and non-Hodgkin lymphoma. The final stage of untreated HIV infection is AIDS (Acquired Immunodeficiency Syndrome), marked by a critically weak immune system and a high risk of life-threatening infections. Additionally, untreated HIV can lead to neurological complications and severe weight loss (wasting syndrome).

HIV testing typically involves testing a sample of a person's blood or oral fluid for the presence of HIV antibodies or antigens. The most common tests are the antibody screening test (also known as the ELISA test) and the rapid antibody test, which can provide results in 30 minutes or less. For those with a higher risk of infection, such as sexually active individuals with multiple partners, intravenous drug users, or partners of HIV-positive individuals, it is recommended to get tested at least once a year. Regular testing is crucial because it ensures early detection, which is vital for effective treatment. Early treatment with antiretroviral therapy (ART) can control the virus, maintain health, and prevent transmission to others.

As of now, there is no vaccine available to prevent HIV infection. Developing a vaccine for HIV has proven to be exceptionally challenging due to several factors. HIV is a highly mutable virus, meaning it changes rapidly and frequently, making it difficult for scientists to target with a vaccine. Additionally, HIV attacks the immune system itself, the very system that a vaccine aims to activate and strengthen. Despite these challenges, research in this area is ongoing. Scientists are exploring different approaches to an HIV vaccine, including using different parts of the virus to trigger an immune response and using novel delivery systems. While an effective HIV vaccine remains a crucial goal, current prevention strategies such as safe sex practices, pre-exposure prophylaxis (PrEP), and post-exposure prophylaxis (PEP) are vital in controlling the spread of HIV.

Condoms are highly effective in preventing HIV transmission when used correctly and consistently. They act as a physical barrier, preventing the exchange of body fluids during sexual activity, which is a primary mode of HIV transmission. Latex condoms are particularly effective because they are impermeable to even the smallest pathogens, including viruses like HIV. It is important, however, to use condoms correctly to ensure their effectiveness. This includes using a new condom for each act of intercourse, checking the expiration date, and using water-based lubricants with latex condoms to avoid breakage. When used consistently and correctly, condoms significantly reduce the risk of HIV and other sexually transmitted infections.

No, HIV cannot be transmitted through casual contact. It's a common misconception that HIV can be spread through touch, sharing food, kissing, or using the same toilet as someone with HIV. HIV is transmitted through specific body fluids from a person with HIV. These fluids include blood, semen, pre-seminal fluids, rectal fluids, vaginal fluids, and breast milk. The virus requires a direct entry point, such as cuts or sores, or direct injection (for example, through needle sharing) to spread. Everyday social contact, like hugging, shaking hands, or sharing utensils, does not provide a route for HIV transmission. Understanding these facts is crucial for reducing the stigma associated with HIV and for informed health practices.