I am not an anti vaxxer, but just someone who is concerned with how they can have a vaccine for covid, but nothing for cancer or aids/hiv
A perfectly reasonable question for a layperson to ask - and, I might add, a related question would be: the common cold is caused by a corona virus, so why the hell can't we have a vaccine against that?
The thing is, there are answers out there and all you have to do is spend a little time reading in order to find them. You shouldn't get the answers from me, because I'll mangle them. But just to demonstrate: I done my best to read and absorb trustworthy sources geared to laypeople. So here goes, the Puspa awkwardly-worded 101 course on Why Some Stuff Has Vaccines and Some Stuff Doesn't:
First thing you have to know (and I assume you do, but just in case): vaccines work on viruses. They don't work on bacteria, genetic disorders, injuries, or any of the other myriad causes of illness and disorders. Just viruses!
As to cancer, there is no "cancer virus." While some cancers are suspected to have a viral component, all kinds of things, like exposure to certain chemicals - to the best of our imperfect but ever-improving knowledge - start the cancerous process of cell replication running amok. You can't vaccinate against, for example, cyclamate consumption, or lack of exercise, or stress - all of which can contribute to getting certain forms of cancer.
HIV is caused by a virus, but for reasons I don't understand well because I'm not an immunologist, its mechanisms are atypical. Because of its unusual features, we don't know how to create a vaccine.
Regarding the common cold, that is caused by a corona virus - or rather zillions of them, and they mutate. So a single vaccine couldn't possibly protect you. It's not practical to have 3500 different vaccines (number pulled out of one of my orifices, ahem, I don't know the real number we'd need).
On a related front, consider the flu vaccine (though flu is not caused by a corona virus) and why people need to get it every year and it varies in its effectiveness: it is because the virus mutates and every year vaccine makers have to predict in what direction it is going to go, and come up with a vaccine that defends against that predicted strain. It's like H5N1 ("bird flu") - the name relates to the number and types of spikes on the surface of the virus. That can mutate and it changes both the potential severity of the disease and the specific make-up of the vaccine that's effective against it.
NOTE - some viruses are more stable than others, which is why a measles vaccine will last you indefinitely but a flu vaccine won't. At the beginning, scientists weren't sure about SARS Corona Virus 19, the one that we're dealing with. They were scared that it would mutate too quickly and extremely to make a vaccine practical. Thankfully that is apparently not the case.
So there you go. I'm not trying to give you a science lesson. You need a much better source than I am. But my point is that
there are answers to your questions and even a layperson can find them and understand them reasonably well.
Sure, there is a lot of junk on the internet, but generally speaking sources like Mayo Clinic, NIH, and others are reputable. Just use your critical thinking skills.
I try and listen(or read) to both side of the argument.
That's fine up to a point, but don't fall into the trap of false equivalency. Borrowing the way I recently read someone else put it: "If there are two sides to an argument and one is arguing that 2+2=4 and one is arguing that 2=2=5, I don't have to give them equal time."
'Kay, I'll shut up now