A recent NEJM letter indicates that serum from individuals (n=15) who received the Pfizer vaccine is adequate to neutralize tested variants.
Y Liu et al. NEJM 2021; DOI: 10.1056/NEJMc2102017. Full text Neutralizing Activity of BNT162b2-Elicited Serum
“All the serum samples efficiently neutralized USA-WA1/2020 and all the viruses with variant spikes.”