I am going to post here, since it does get more views. Go to Pinterest and put in baby proofing spiral staircase. I did and tons of ideas came up.

Gates should suffice if child minder is watchful and not watching TV or texting!

Are the railings too far apart? More importantly, are these the only stairs? If there is another set of stairs, I'd turn this into a plant stand and just not use it for a few years.

In my (limited) experience as a friend/next-door-neighbor who had this childproofing problem with visiting grandchildren, they took them out and made new stairs. Just didn't work well enough.

They are so beautiful. I think I'd try to convince spouse that gates to limit unaccompanied babies would work until the child is old enough to be taught to navigate them safely, and then never allowed to play on them. I would have loved a house with that staircase when I was a child.

Babies are only toddlers for a blink of an eye. I never permanently change out anything for the children in my house. They get redirected and when older face a consequence for using thing improperly or dangerously. A gate hinged with screws at the top and the bottom one can be just the accordion one if desired. Tell your DH that in a year or so your child will be climbing similar stair structures with ease at parks to access slides and your own stairs will be a non issue very soon so I would keep it simple too.

"Aesthetically" is the challenge. As stated this time is sooo short not sure the effort for aesthetics is worth it. The go to barriers and what not one sees parents resorting too may not be beautiful but they are practical, do the job and get them through. The question is do adults have to use those stairs? The barrier one might choose changes if others have to use the stairs. If DH is concerned about company's judgments--WHO HAS TIME TO ENTERTAIN WITH A TODDLER would be my response. LOL I have often wondered what people with children do in these situations...let us know what you find that works for you, please.

I wouldn't be so worried about the risers as they look to have less than 4" open space. For the spindles they look more than code (more than 4") and I would likely do something just because I would feel very awful if something preventable happened (kids getting head stuck or falling through). It only takes the blink of an eye for sure.

The more permanent option would be to weld additional spindles and repaint the rail/spindles with the satisfaction that the stair will now be permanently up to code.

Or you can buy clear Stair Banister Shield that will do the trick:

https://www.amazon.ca/Cardinal-Gates-Banister-Shield-Clear/dp/B002CGRTFY

No suggestion just sympathy. We have lived with a very similar staircase for 25 years. Every small child who has ever come in the house is fascinated with those stairs. The very small ones can & will stick their heads through the vertical posts. Gates across the bottom & top and close supervision of the littles has gotten us through it.

Hm, it's not just gates and watchful eyes --- stuff can happen in a fraction of a second, even without watching TV or texting --- but I can also see a foot slipping through the opening of the riser.

We had something similar. I can still hear my mom screaming. I think I still have scars on my shins. But nobodies head ever got stuck.

When my kids were little we put plexiglass on our stairs. Really couldn't tell it was even there and it made for a happy mama!

can you give me info on where you purchase your stair treads rug grips, and did the adhesion hold up on them?

For the stair tread, I just went to BiMart (Kmart type of store in Oregon) and bought shelf liners on the heavier-duty side, and I cut them to shape of the step. They're spongy foam, non-adhesive, and I use tablecloth clips (pictured) to anchor them at the outer edge of the steps. The same shelf liners have lasted 3+ years, surprisingly durable.

For the childproofing, I decided to take the advice of the gate-people, and I made my own. Here are pictures. One child is now 4, the other is 2 1/2 and they've both had no problem with the stairs, and they are both now allowed to go up and down on their own (without carrying any toys!).