Why aren't there HIV vaccines?

In 2019, viral pneumonia of unknown origin was detected. It was later classified as novel coronavirus or "nCoV". After the detection, we could see various successful vaccines had developed within one year. This brings us to the question, why aren't there any HIV vaccines after 3 decades? HIV is a member of the retroviridae family. It is a DNA virus and mutates super fastly. It integrates within the host cell within 72 hours. HIV is a headache to doctors because it's regarded as the greatest con man of the virus world. The virus itself doesn't do any harm. As a con man, it just impersonates the cells responsible for the immune system(CDT+ cell, CD4 cells, WBC, etc). It kills the cell it replaced. The immune system thinks of HIV as a friend all the time. This way, by scamming the immune system, it destroys the immune system. Our body then becomes vulnerable to the simplest disease there could ever be. Vaccine-induced protective immunity generally are being done in the following ways- 1. Neutralizing antibodies 2. non-neutralizing antibodies 3. Cytotoxic lymphocytes Option 1&2 are being regarded as the only shot now. That's being said after a successful trial in Thailand(after 6 failures). The goal of the HIV vaccine is to induce HIV-1 bnAb(broadly neutralizing antibodies). But this process is based on many unknown factors such as- 1. Viral infection works by receptors. A normal vaccine just blocks that receptor site. Such was the case in many vaccines including the novel coronavirus vaccine.HIV's receptor site is EnV glycoprotein. Unlike other viruses, they are densely and poorly assigned. So it becomes incredibly difficult to neutralize them.HIV-1bnab fails because of this. 2. Molecular mimicry by env glycoprotein induces cross-reaction with the human protein.Another reason for failure. 3.HIV-1bnabs have unusual traits such as autoreactivity, long third heavy chain complementary determining regions (HCDR3s), and are enriched in rare somatic mutations — all of which make bnAb precursors either very rare owing to immune tolerance deletion or difficult to activate. In other words, they're considered harmful instead of HIV by the body. Now you get why HIV is called a conman.

Sars-CoV-2 vaccine, after being injected within the body, easily induces the antibodies prepared against the n-CoV. Then it's just a matter of time till corona gets kicked out or killed. But after injecting the HIV-1bnab, there's only a 10% chance for your immune system to develop immunity against HIV after 1 year. Not close enough to get called a vaccine. But the pandemic has shown us how people of different countries act as one. We hope by the collaboration of all scientists, we'll be able to conquer HIV.

Retold by-Mahdi ashraf (Academics Executive) Source(s):Google,Nature