Why is it difficult to develop vaccine against hiv?
Answers
At a time when many infectious diseases were being brought or kept under control with global vaccination efforts in the 1990s, the human immunodeficiency virus (HIV), only identified in 1984, infected millions worldwide. From 1990 to 2014 the number of people living with HIV rose from 8 million to 36.9 million; since the beginning of the HIV/Acquired Immune Deficiency Syndrome (AIDS) epidemic, AIDS has claimed more than 34 million lives.
HIV is a major public health concern not only because it can’t yet be prevented by vaccination, but also because those it infects are infected for life with a virus that targets their immune system - making them more prone to other infections. The virus kills immune T helper cells called CD4+ cells, which are the coordinators of the human immune system. This is where the “Acquired Immune Deficiency Syndrome” name comes from: when HIV kills enough CD4+ cells, the infected person’s immune system is unable to fight off infections it could ordinarily control. When the number of CD4+ cells drops below a certain point, a person is considered to have progressed from HIV infection to AIDS. People with AIDS are more susceptible to many types of infections, including those it could normally fight off, including types of pneumonia, tuberculosis, and shingles, as well as certain cancers.
In the early years of the AIDS epidemic, people infected with the virus faced certain death, often within just a few years after infection. Though many in the medical and public health fields lobbied to direct funding and research efforts to the growing crisis, U.S. government response was very slow. Factors that led the U.S. government to take action included vocal activism by people infected with HIV and their allies as well as persistent efforts by advocates in the scientific world. They highlighted the need for effective treatments, the need to improve access to effective treatments once they were developed, and the importance of reducing the stigma of living with HIV infection.
Mark me as Brainliest...
pls follow meeeeee.....