Was a September 18 tweet by someone named John Cammo (@johncammo) predicting that President Trump would become infected with COVID-19 in October the only one to make that assertion? No. There were several prior tweets that made the same prediction.
"@joshtpm Trump's October surprise will be the announcement of "his infection." Fake, but quite dramatic. This twist will blow Biden off the screens, the "Trump COVID watch" dominating every minute of every day. Then, 14 days later, Trump will emerge, 100% cured by hydroxychloroquine."
This is what the post looked like on Twitter at the time of writing:
(Source: Twitter screenshot taken on Fri Oct 2 18:38:38 2020 UTC)
The September tweet saying Trump would contract COVID-19 has been repeated widely, with many of the commentaries appearing on Facebook. But it's just social media's version of winning the lottery. Lots of people play the lottery, so someone is likely to win. Same with social media: Lots of people make all sorts of predictions, so some are bound to be right.
Not only that, but the September tweet wasn't the only one to make the Trump COVID prediction. There have been many, some dating to 2019.