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woodsboro2 t1_iylkts5 wrote

Why has it taken so long to develop a vaccine for HIV? I know Covid vaccine research had massive amounts of funding behind it, but it still came about relatively quickly. What’s the difference?

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alf666 t1_iylmdbp wrote

Keep in mind, I'm trying to remember my high school health class from 15-ish years ago, but I will try to explain as best I can.

If someone has better or more up-to-date info, feel free to correct me.

Viruses replicate by breaking into healthy cells and rewriting the cell's DNA to make the cell create more copies of the virus until the cell dies.

Covid has a recognizable molecular pattern that it uses to attach to cells when breaking into them, and that pattern can be "recognized" by your immune system (e.g. giving someone a vaccine so the immune system can "learn" which molecular patterns to attack), which allows the immune system to fight Covid.

The problem with HIV is that it specifically attacks cells that are part of the immune system, and as it is rewriting a target cell's DNA, it also flags its own molecular pattern as "safe" to prevent the immune system from fighting back.

The result is an immune system that is weakened on two fronts:

  1. the immune system's cells are replicating HIV before dying early

  2. the immune system does not recognize HIV as something it should attack in the first place, allowing HIV to run rampant

The result is a heavily weakened immune system, which allows other germs to run rampant as well, causing chronic illness (and eventually death when the immune system is fully overrun) in someone who has HIV.

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woodsboro2 t1_iynico4 wrote

That makes so much sense, thanks for explaining!

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