I will copy some things from Reddit threads I have bookmarked about this topic.

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Vaccines have been the driving factor in increasing life by about 80% vs. when we did not have them:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4151714/

The cons are negligible compared to the pros.

Should we talk about the potential harm done by seatbelts when telling people whether to use them or not? Or should we recognize they are overwhelmingly positive and encourage people to wear them?

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Antivaxxers do not only harm themselves. I realize that many people have brought up “at risk populations” that are unable to get the vaccine for medical reasons, but that’s not the only reason.

More unvaccinated carriers and afflicted result in a greater likelihood that the disease mutates into a version that resists the initial vaccine. The immune system creates antibodies to specific sites on “invaders” called epitopes, if the sequence encoding those epitopes change, antibody bonding will be disrupted.

Vaccine immunity isn’t 100% even in healthy individuals. Immunity wanes with time and scheduling is based on the average person. Some individuals lose the immune memory more rapidly and would need incredibly expensive tests to know if this is the case (as a preventative measure) or be proactive enough to frequently get blood tests for specific vaccine antibodies to demonstrate maintained immunity. This group is also at risk.

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Data on vaccine efficacy and safety is among the most transparent in medicine specifically because the medical community desperately wants to convince people like you who are skeptical but genuinely want to learn more.

Here is the CDC website on vaccine safety. There is detailed information on the risks of specific vaccines, links to safety, etc. You may not trust them, but one important thing to note is that they don’t deny that there are risks. There is a lot of discussion of side effects, most of which are minor but can be really scary, like seizures. But they do point out other risks. For example, the MMR vaccine:

Extremely rarely, a person may have a serious allergic reaction to MMR vaccine. Anyone who has ever had a life-threatening allergic reaction to the antibiotic neomycin, or any other component of MMR vaccine, should not get the vaccine.

The medical community also doesn’t hide when a vaccine is so dangerous that it’s not worth the risk. RotaShield was approved as a vaccine against rotavirus in the ‘90s. Some infants started developing intussusception, a type of bowel obstruction, soon after getting the vaccine. After some investigations, the vaccine was withdrawn. The whole story is here

So let’s walk through that—a vaccine is released. Data emerges that there is a risk it is harming some babies. The risk was still really rare—1 or 2 additional cases for every 10,000 babies vaccinated. It was so rare that you statistically couldn’t identify it in a trial of 10,000 patients. The condition itself was treatable in almost all cases. The vaccine was withdrawn anyway.

What that translates to—the vaccine can kill people. It probably has killed people. But it is so rare that the risk is worth the benefits, especially since we can take steps to identify and mitigate the risks.

Let’s talk about efficacy. Here too you can find honest info about how effective we know vaccines to be. Take the flu vaccine—it’s incredibly variable each year how well it will work. The medical community encourages everyone to take it anyway but they don’t hide the fact that it sometimes doesn’t work that well. Here is a chart of effectiveness over the last decade of so. The vaccine makers flat out miss in some years—10% effectiveness in 2004 is terrible. But they don’t hide those facts.

So let’s look at the most common vaccines. Sure, they might cause previously unidentifiable serous harm in some cases. I can’t rule it out. But it is so rare that literally no one can make a compelling data-driven case that the problem exists, weighted against the well-proven benefits of protecting against some truly terrible diseases. If you want to claim that contrary studies are being hidden, I’ll need to see some evidence of that, and why those are hidden when lots of other “bad” news is easy to find on the CDC’s on websites.

Let’s also talk about profit motives. Vaccines are not that profitable. Maybe some of the newest ones, but generally they aren’t a huge money maker, especially not for the vast majority of doctors administering them. The standard vaccines for the American market were so unprofitable that the big concern 10’years ago was that drug companies were abandoning the market.

You know what makes a lot more money than preventing disease? Treating disease. What profit motive is there in pushing one shot for polio against a lifetime of selling expensive treatment for a paraplegic polio patient? An MMR shot is not nearly as profitable as a hospital stay for measles complications. If anything, vaccines reduce the profits of drug companies because there are fewer sick people to sell drugs to.

On a more emotional level, parenting is fucking scary. Every decision you make is simply weighing risks and benefits and hoping that you’re making the best bets possible. It is hard to watch doctors put a needle in your kid while they scream. The side effects can make you question your judgement—my youngest basically got mild measles symptoms from his MMR and was miserable for almost a week. But all the data and evidence we have available says that vaccines are worth it.

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There is tremendous amounts of research on the risks of vaccines. The public health community is incredibly transparent about documenting those risks and making the underlying studies available.

If you click through that website, all the data is there. The WHO also has a good page here.

Take the MMR, for example. Here is the more detailed safety data on the vaccine. At the extreme, they acknowledge there is a risk of a complication involving brain swelling, because there have been three known cases, only one of which is linked with confidence to the vaccine and which happened in people who were otherwise immunocompromised. For a vaccine that has been given millions of times, three documented cases is functionally the same as zero risk.

They also identify other potential side effects—up to 1 in 40,000 children might develop an issue with blood clotting, which isn’t life threatening and is treatable with a transfusion.

Fevers are the most common side effect—both my kids get them after vaccines—and in some cases the fever is bad enough to cause seizures. Still rare, in the 1 in a few thousand range, but common enough that you may meet someone who had it happen.

In case you’re worried that doctors dismiss these side effects, the medical community has shown they will pull vaccines when problems emerge. For example, RotaShield was approved as a vaccine against rotavirus in the ‘90s. Some infants started developing intussusception, a type of bowel obstruction, soon after getting the vaccine. After some investigations, the vaccine was withdrawn. The whole story is here.

So let’s walk through that—a vaccine is released. Data emerges that there is a risk it is harming some babies. The risk was still really rare—1 or 2 additional cases for every 10,000 babies vaccinated. It was so rare that you statistically couldn’t identify it in a trial of 10,000 patients. The condition itself was treatable in almost all cases. The vaccine was withdrawn anyway.

The common theme is that the likely side effects are known, researched and, in almost all cases, not serious. When they are, the vaccine is pulled. Febrile seizures are scary as a parent, but your kid will be fine. “Proven safe” means “incredibly unlikely to cause permanent harm,” not “absolutely free from side effects.”

The most serious problems are associated with people who are allergic to the vaccines or people who are immunocompromised. These people should not get vaccines. Doctors know that and will tell patients (or their parents) in those situations not to get vaccinated.

The fact that some people can’t get vaccinated because their doctors have advised against it is why it’s so important the rest of us get vaccinated, even if it means your kid might get a fever or even have a scary seizure. It’s not just a question of deciding you don’t care if your kid gets measles. Those people depend on herd immunity to stay healthy, and parents who choose not to vaccinate their kids even though their kids would almost certainly be fine are choosing to put those other people at more risk.