HIV vaccines - an update

The magic of mRNA is not being applied to building vaccines for the HIV-ADIS pandemic.

 HIV vaccines - an update

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• The story: The HIV-AIDS menace arrived in 1980s, and has stayed alive since then. All attempts to build a lasting vaccine have failed, due to the constantly mutating virus, and medication is the way to manage HIV-AIDS. Scientists have struggled since decades to build a reliable vaccine. WHO estimated that there were around 37.7 million living with HIV as of 2020.
• HIV (Human Immunodeficiency Virus): This virus attacks CD4, a type of White Blood Cell (T cells) in the body’s immune system. T cells are those cells that move around the body detecting anomalies and infections in cells. After entering the body, HIV multiplies itself and destroys CD4 cells, thus severely damaging the human immune system. Once this virus enters the body, it can never be removed. The CD4 count of a person infected with HIV reduces significantly. In a healthy body, CD4 count is between 500- 1600, but in an infected body, it can go as low as 200. A weak immune system makes a person prone to opportunistic infections and cancer. It becomes difficult for a person infected with this virus to recover from even a minor injury or sickness.
• mRNA magic: In the pandemic, the magic of messenger RNA was discovered, when a Covid vaccine was successfully developed. Now, Moderna, the Massachusetts-based American biotechnology company, has started human trials for its novel mRNA vaccine (mRNA-1644) for HIV (Human Immunodeficiency Virus) also. This is the first trial for an mRNA vaccine for HIV after the success of mRNA vaccines with Covid-19.
• mRNA vs Traditional vaccines: Medicines are given to sick people, and vaccines to healthy people (to prevent sickness).

1. Vaccines work by training the body to recognise and respond to the proteins produced by disease-causing organisms, such as a virus or bacteria.
2. Traditional vaccines are made up of small or inactivated doses of the whole disease-causing organism, or the proteins that it produces, which are introduced into the body to provoke the immune system into mounting a response.
3. But mRNA vaccines trick the body into producing some of the viral proteins itself. They directly use the mRNA - messenger RNA - the molecule that puts DNA instructions into action. Inside a cell, mRNA is used as a template to build a protein.

• mRNA vaccine for HIV: The vaccine is expected to work similar to the Covid-19 vaccine — by getting the body’s cells to produce the HIV virus’ spike protein triggering an immune response. The larger purpose of stimulating the B cells is to generate what are called broadly neutralising antibodies (bnAbs), which are specialised blood proteins that attach to the surface proteins of HIV and disable them by accessing key but hard-to-reach regions on the virus.

1. B-cells fight bacteria and viruses by making Y-shaped proteins called antibodies, which are specific to each pathogen and are able to lock onto the surface of an invading cell and mark it for destruction by other immune cells.
2. Over the last decade, there have been advances in identifying new bnAbs from HIV-infected individuals that were seen to target very specific sites in the outer envelope of the HIV.
3. Lab-based analysis and tests on animals have improved the understanding of how the knowledge of these sites can be used to make immunogens. An immunogen refers to a molecule that is capable of eliciting an immune response by an organism’s immune system, whereas an antigen refers to a molecule that is capable of binding to the product of that immune response.
4. An immunogen is necessarily an antigen, but an antigen may not necessarily be an immunogen.

• Benefits: The RNA-based immunogens are believed to be a promising alternative because they do not involve the use of a live virus, can be made relatively easily, can be quickly deployed and safely administered.
• Challenges: The experience with the Moderna and Pfizer vaccines has shown that cheaper vaccines are not available easily. Of the people living with HIV, over two-thirds are in Africa. Further, the m-RNA vaccines are sensitive to temperature in storage, and is a challenge for developing countries. Then, HIV has mutated into several variants and is an insidious virus, and will be many years before definitive proof of the success of the m-RNA approach can be established.
• Indian and global initiatives: India has been very successful in its National Aids Control programme, and is recognised worldwide for it. Some initiatives are - The HIV & AIDS Prevention and Control Act, 2017, Project Sunrise, 90-90-90, The Red Ribbon, Global Fund to Fight AIDS, Tuberculosis and Malaria (GFATM).
• EXAM QUESTIONS: (1) Explain the basic functioning of the HIV virus, once inside a human body. What makes it quite dangerous? (2) Explain the basic idea inherent in the mRNA vaccines, that make them different from all traditional vaccines. (3) Science may make vaccines, but it's politics that'll get them to the needy. Do you agree? Critically analyse.
  

#Vaccines #mRNA #HIV-AIDS #NACO #Virus

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