AIDS

艾滋病

Evidence-backed information EN 7/7 applicable sections · ZH 7/7 applicable sections Updated Oct 23, 2026

AIDS is the advanced stage of HIV infection caused by HIV, which was isolated in 1983 and leads to progressive immune deficiency ^[1]^[2]. Clinical features vary by stage, ranging from asymptomatic or influenza-like early illness to severe illnesses associated with immune weakening ^[1]. HIV can spread more easily soon after infection and through sexual and mother-to-child transmission, while testing, ART, PrEP, PEP, and prevention of mother-to-child transmission reduce risk ^[1]. People living with HIV/AIDS are also vulnerable to opportunistic fungal disease such as histoplasmosis, which has been reported with high prevalence and mortality in this group ^[3].

Read the full clinical and epidemiological profile 8

Definition

AIDS is the advanced stage of HIV infection caused by HIV, which was isolated in 1983 ^[1]^[2]. The infection course includes primary infection, chronic infection, and AIDS, with progressive immune weakening and dysregulated cytokine responses contributing to disease ^[1]^[4]^[5]. AIDS is therefore a stage-specific classification of HIV disease rather than a separate infection ^[2]^[5].

Clinical features

Clinical features vary by stage of HIV infection; early weeks may be asymptomatic or include influenza-like illness ^[1]. As infection progresses, the immune system is weakened, leading to additional signs and symptoms, and untreated HIV infection can result in severe illnesses ^[1]. HIV can also worsen other infections, such as hepatitis B, hepatitis C, and mpox ^[1].

Epidemiology

Among immunocompromised groups including people living with HIV/AIDS, histoplasmosis has been reported as a notable health challenge, with prevalence of 22%-44% in people living with HIV and mortality of 21%-53% in a systematic review ^[3]. Histoplasmosis is primarily prevalent in Africa and the Americas, with emerging reports globally ^[3].

Transmission

HIV spreads more easily in the first few months after infection, when many people are unaware of their status ^[1]. Sexual transmission and mother-to-child transmission are important exposure pathways, and antiretroviral treatment that suppresses virus to no evidence in the blood prevents sexual transmission ^[1]. PrEP and PEP are biomedical prevention options for high-risk exposures, and risk-reduction approaches address contexts such as sexual practices and substance use ^[1]^[6].

Risk groups

Prevention guidance identifies HIV-negative people who may use PrEP, people at high risk of contracting HIV who may consider PrEP or PEP, and mothers with HIV as relevant to preventing mother-to-child transmission ^[1]. People living with HIV who are taking ART and have no evidence of virus in the blood are also relevant to preventing sexual transmission ^[1].

Prevention

HIV prevention is based on access to testing and ART, use of PrEP by HIV-negative people to reduce acquisition risk, and PEP after possible exposure ^[1]. ART reduces viral load and can prevent sexual transmission, while antiretroviral interventions can prevent mother-to-child transmission ^[1]. PrEP and PEP efficacy, prescribing guidance, efficient use, and treatment retention are part of public-health prevention strategies, including nonjudgmental risk-reduction education ^[1]^[6].

Surveillance note

GlobalID source-data note: Brazil publishes separate SINAN series for AIDS in adults and AIDS in children; these are population slices of the same AIDS concept, not different diseases. Norway reports AIDS separately from HIV infection. Do not add overlapping AIDS and HIV series as though they were disjoint case totals.

References

1 World Health Organization. HIV and AIDS [Internet]. cited 20 May 2026. Available from: https://www.who.int/news-room/fact-sheets/detail/hiv-aids
2 Shioda T et al. [The history of HIV]. Uirusu. 2025. PMID: 41882858. doi: 10.2222/jsv.75.135. PubMed: https://pubmed.ncbi.nlm.nih.gov/41882858/
3 Dao A et al. Histoplasmosis: A systematic review to inform the World Health Organization of a fungal priority pathogens list. Med Mycol. 2024 Jun 27. PMID: 38935903. doi: 10.1093/mmy/myae039. PubMed: https://pubmed.ncbi.nlm.nih.gov/38935903/
4 Emilie D et al. Cytokines in HIV infection. Int J Immunopharmacol. 1994 May-Jun. PMID: 7927984. doi: 10.1016/0192-0561(94)90026-4. PubMed: https://pubmed.ncbi.nlm.nih.gov/7927984/
5 Barrionuevo-Cornejo C et al. Lymphadenopathies in human immunodeficiency virus infection. Semin Diagn Pathol. 2018 Jan. PMID: 29277280. doi: 10.1053/j.semdp.2017.12.001. PubMed: https://pubmed.ncbi.nlm.nih.gov/29277280/
6 Yingling C et al. Pharmacoprevention of Human Immunodeficiency Virus Infection. Nurs Clin North Am. 2020 Sep. PMID: 32762861. doi: 10.1016/j.cnur.2020.06.006. PubMed: https://pubmed.ncbi.nlm.nih.gov/32762861/
7 Wikipedia contributors. HIV/AIDS - Wikipedia [Internet]. Wikipedia. cited 2 Sept 2026. Available from: https://en.wikipedia.org/wiki/HIV%2FAIDS