New studies done in the US, Canada & Italy shows that better results are obtained with longer dosing intervals. A second dose at 16 weeks did not significantly improve humoral (antibody) responses among individuals who were infected prior to the first dose, but it significantly enhanced these responses among infection-naïve individuals.
They found that with the SARS-CoV-2-naïve group, immunization elicited antibodies with weak neutralizing activity but strong Fc-mediated functions three weeks following the first dose.
These responses declined over the following weeks. However, administration of a second dose 16 weeks later significantly enhanced these responses. Also neutralizing activity against some VOCs, VOIs and even the divergent SARS- CoV-1 was significantly increased.
SUMMARY
While the standard regimen of the BNT162b2 mRNA vaccine includes two doses administered three weeks apart, some public health authorities decided to space them, raising concerns about vaccine efficacy. Here, we analyzed longitudinal humoral responses including antibody binding, Fc-mediated effector functions and neutralizing activity against the D614G strain but also variants of concern and SARS-CoV-1 in a cohort of SARS-CoV-2 naïve and previously infected individuals, with an interval of sixteen weeks between the two doses. While the administration of a second dose to previously infected individuals did not significantly improve humoral responses, we observed a significant increase of humoral responses in naïve individuals after the 16-weeks delayed second shot, achieving similar levels as in previously infected individuals. Our results highlight strong vaccine-elicited humoral responses with an extended interval BNT162b2 vaccination for naïve individuals.
They found that with the SARS-CoV-2-naïve group, immunization elicited antibodies with weak neutralizing activity but strong Fc-mediated functions three weeks following the first dose.
These responses declined over the following weeks. However, administration of a second dose 16 weeks later significantly enhanced these responses. Also neutralizing activity against some VOCs, VOIs and even the divergent SARS- CoV-1 was significantly increased.
SUMMARY
While the standard regimen of the BNT162b2 mRNA vaccine includes two doses administered three weeks apart, some public health authorities decided to space them, raising concerns about vaccine efficacy. Here, we analyzed longitudinal humoral responses including antibody binding, Fc-mediated effector functions and neutralizing activity against the D614G strain but also variants of concern and SARS-CoV-1 in a cohort of SARS-CoV-2 naïve and previously infected individuals, with an interval of sixteen weeks between the two doses. While the administration of a second dose to previously infected individuals did not significantly improve humoral responses, we observed a significant increase of humoral responses in naïve individuals after the 16-weeks delayed second shot, achieving similar levels as in previously infected individuals. Our results highlight strong vaccine-elicited humoral responses with an extended interval BNT162b2 vaccination for naïve individuals.
