Not sure what you are talking about but
NPR had an article about difficulties purchasing a second batch of Pfizer vaccines. Trump eventually purchased 200M Pfizer vaccines. There was some sort of an option to buy between 100M and 500M extra vaccines when Trump ordered the first 100M Pfizer vaccines. I couldn't make out if that was brought into play for the purchase of the second 100M Pfizer vaccines.
Trump ordered 200M vaccines from Pfizer; enough for 100M
Trump ordered 200M vaccines from Moderna: enough for 100M
Trump ordered 100M vaccines from Johnson&Johnson enough for 100M
Biden ordered 100M vaccines from Pfizer; enough for 50M
Biden ordered 100M vaccines from Moderna: enough for 50M
What's next? Biden will probably be taking the credit for helping get these vaccines to market sort of like when Al Gore invented the internet.
I thought it was funny when Biden was promising to bring vaccine distribution up to 1M/day and then he found out that Trump's existing program was already distributing 900,000/day. Biden then said he would raise that number to 1.5m/day. But it isn't Biden magic. Those Johnson and Johnson vaccines Trump ordered are supposed to be all available by the end of June. Biden's FDA is still holding them up. Meanwhile, Democrats contributed to fighting Covid by having two impeachments. Whoopie.