TL;DR: Abortions only affect the mother and her fetus. Not getting vaccinated negatively affects yourself and others by putting you at a higher-risk as well as leaving room for the virus to mutate and hurt more people than would have been.

Honestly, abortion is kind of tricky to justify since in reality it literally does kill the fetus. The current standings held by people who support it is that the baby in most cases isn't really a person yet and while it does have a heartbeat it doesn't have the brain capacity to give a fuck about anything. It's cruel, yes, and an argument can be made against that saying that that argument is like saying people with mental disabilities who don't have the brain functionality to give a fuck about anything can be killed. The issue with this is that those people already exist and are alive on their own, whereas a 7-15 (on average) week old fetus could not survive outside of the womb due to being completely dependent on the mother. Another standing is that since the fetus is basically an extension of the mother's body, it should be her decision to choose what to do with it.

While adoption is an option, some pregnant women get abortions because they do not want to have to go through the physical and (sometimes) mental pain that pregnancy causes as well as not have to risk dying at childbirth, something that can sometimes happen unexpectedly to anyone. So at this point, it comes down to either the few-month-old fetus or the already-alive mother, and in all cases, it should be about the well-being of the mother. Of course, there's a point where pre-born babies do start to have a certain level of brain functionality where killing it can't reasonably be argued to be moral, which is why there are already laws in most places preventing abortions from being done after about 20ish weeks (I may be wrong about this). I've seen people say "don't have sex if you're not ready for a child" which is a fair point to make since the purpose of traditional male-female sex is to make a child and I don't really have a good rebuttal against it other than sex being good for mental health as well which is why contraceptives should be more widely available and affordable.

Now, not getting vaccinated against covid prevents your body from being able to fight off the virus as well as it could while vaccinated. This may result in no side effects, mild to severe side effects, or death. By not getting the vaccine, you are taking the chance of any of those possibilities coming true for you and it is your right to choose to take that risk or not. However, by allowing the virus to healthily reside in your body and benefit from living inside, you are allowing the virus to potentially mutate into a more severe version of itself, which is what we are seeing now with the Delta variant. People may think they don't need the vaccine because they were completely fine when they got covid before, but if enough people don't get vaccinated, theres a very good possibility that may not be the case next time when they contract an even stronger variant. This can also harm vaccinated people as well, since the virus could eventually mutate so much to the point where the variants aren't affected if a person is vaccinated.

Abortions and refusing vaccines both affect the individuals body and it is the right of the individual to do either, however, only refusing the vaccine can negatively affect other living people as well.