Epidemiology

To control the COVID-19 pandemic, high COVID-19 vaccination coverage is urgently needed in each country worldwide. According to Our World in Data COVID-19 vaccination tracking, by the end of April, 2021, the proportion of individuals who had received at least one dose of vaccination was 62% in Israel, 51% in the UK, 43% in the USA, and 28% in Germany. However, this proportion was quite low in other countries, such as Russia (8%) and South Korea (7%). Although Japan is preparing to host the Summer Olympic Games in Tokyo, only 4% of the population had been vaccinated as of May 21, 2021.

The identification of HIV led to the development of the first commercial blood test for the detection of the virus, which was approved by the FDA in March, 1985. The test consisted of an enzyme-linked immunosorbent assay that detected antibodies against the virus in the blood and was an unprecedented scientific breakthrough at the time, as it was developed in only 9 months. The test was initially used to screen blood products in blood banks; however, by March, 1986, testing was extended to people in high-risk groups. Investigation of the viral replication cycle led to the identification of the first antiretroviral drug, zidovudine, which was licensed by the FDA in March, 1987. Zidovudine, a reverse transcriptase inhibitor, decreased the amount of HIV RNA in the blood, and produced a modest benefit in the life expectancy of patients. However, it was almost 10 years later, in 1996, that a three-drug regimen, known as highly active antiretroviral therapy, heralded a new era in the treatment of HIV, and suppressed the concentration of the virus to reduce disease progression and transmission. Another important advance in the fight against HIV was the introduction of pre-exposure prophylaxis (PrEP) for HIV prevention in 2012. Several randomised, placebo-controlled trials have shown that a once-daily PrEP regimen is highly effective in preventing HIV infection.

In the summer of 1981, the US Centers for Disease Control (CDC) documented cases of Pneumocystis carinii pneumonia and Kaposi's sarcoma, usually reported in immunosuppressed patients, in previously healthy young men. The number of cases continued to increase, with the majority reported in men who had sex with men and in people who injected drugs. Notably, the patients exhibited defects in cellular immunity and had a high mortality. In September, 1982, the CDC issued a case definition for the new disease, which they called acquired immune deficiency syndrome (AIDS). The disease was also observed in patients who had received transfusions of blood or blood products, sexual partners of patients with AIDS, and children born to mothers with the disease. Consequently, in March, 1983, the CDC suggested that AIDS might be caused by an infectious agent transmitted sexually, via blood products, or by vertical transmission. However, it would be another year until a retrovirus, later named human immunodeficiency virus or HIV, was confirmed as the cause of the disease.

The HIV/AIDS pandemic remains one of the world's biggest health challenges, particularly in low-income and middle-income countries. Since the first reported cases of AIDS in June, 1981, the disease has claimed the lives of almost 33 million people, and at the end of 2019, UNAIDS estimated that 38 million people were living with HIV. As we approach the 40th anniversary of the identification of the disease, we highlight key moments that defined the HIV/AIDS pandemic over the past four decades.

June 5, 2021 marks 40 years since the first description of cases of what came to be known as AIDS. Since then, remarkable progress has been made in understanding the disease and its treatment. The HIV response globally has not always been smooth but has become a model for community engagement.