Lancet has a new study this week that compares the amount of antibodies produced by boosters.
https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(21)02717-3/fulltext
What makes this study great is it shows different combinations of mixing & matching boosters. So, you can look at the tables to see which booster to get based on what your first two shots were.
For instance, if you got Pfizer for your first two doses:
(95% CI range in parentheses)
Pfizer full dose: 26,171 (21,245 - 32,239
Pfizer half dose: 27,498 (20,109-37,602)
Moderna booster: 30,654 (22,916 - 41,004)
https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(21)02717-3/fulltext
What makes this study great is it shows different combinations of mixing & matching boosters. So, you can look at the tables to see which booster to get based on what your first two shots were.
For instance, if you got Pfizer for your first two doses:
(95% CI range in parentheses)
Pfizer full dose: 26,171 (21,245 - 32,239
Pfizer half dose: 27,498 (20,109-37,602)
Moderna booster: 30,654 (22,916 - 41,004)