I heard on the news today that Merck abandoned two vaccines it was working on because they couldn't be shown to be very effective.

There is a lot of vaccine information available from Tiberious (a US Dept. of Defense site).

Vaccine makers have plans to adjust the existing formulations or offer a booster if needed to deal with the new varieties turning up if they become prevalent. So far the vaccines are effective against most of them.

Biden found the Trump vaccine program in disarray, he talked about it in a press conference today. They're pushing to get a lot more doses made within the next three weeks to boost the daily vaccine administration numbers.