As reported by news-medical, spike protein gets a lot of attention from the host immune system because it is located on the outer surface of the virus (external protein). Scientists have monitored extensively all the genome sequencing data for the coronavirus that is available globally in the Global Initiative for Sharing All Influenza Data (GISAID) database.
Thus, spike mutations D614G is expected to play a major role in modulating the ability of the virus to escape vaccine-induced immune responses.
However, there is evidence to suggest that mutation is possible D614G affect vaccine efficacy is very small.
Because the mutation is not in the spike protein receptor binding domain, the mutation is less likely to affect the ability of the domain to induce a host immune response, which is believed to be a prerequisite for antibody-mediated viral neutralization.
Additionally, most of the ongoing vaccines are being developed against receptor binding domains, and thus, mutations D614G should have no effect on vaccine efficacy.
Another important observation is that the healing serum obtained by people infected with the D614 virus has been found to neutralize the G614-containing virus, and vice versa.