Biology PCR

Can we use Polymerase chain reaction to produce more hepatitis B surface antigen vaccine?

No, it is because an antigen is a protein.
PCR can be used to amplify DNA or RNA fragments, but not for any protein.
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Or must we use gene cloning?

Use PCR to amplify the mRNA of hepatitis B surface antigen, and then clone these mRNA into a vector.
A vector itself would not produce any protein. Transfect vectors into bacteria in order to get protein expressed by bacteria.