Corona note in Std?

Personally, I would skip the Save the Dates due to these circumstances. I sent mine out in February for my July wedding and had to send out another note saying they were uninvited due to social distancing. We cut the guest list from 100 down to 20. I felt absolutely terrible, but it had to be done and everyone understood. Had I known that COVID-19 was coming, I would have waited longer and just have sent the real invitations instead. Putting a note in a STD may make the guests feel uneasy. They'll be wondering if they'll make the cut.

I'd skip the save the dates.
At this point, I'm somewhat regretting telling everyone that was invited to our first wedding that we will see them in October. Because we might not.

A lot of people are putting in notes with their invitations, mostly directing invitees to the website, where all updates will be posted.

That said, it's likely best to not do STDs right now, as we just don't know what the rest of the year will look like.

I included a card in our invitations that said something along the lines of Due to the uncertainty of the world right now we wanted to let you know that at this time our wedding is going forward as planned and that we understand if people are unable to attend or don't feel comfortable attending due to the circumstances and that we can't wait to celebrate with everyone soon.