Short or Long Interval between Priming and Boosting: Does It Impact on the Vaccine Immunogenicity?

Abstract

Characterizing the impact of the vaccination schedule on the induction of B and T cell immune responses is critical for improving vaccine immunogenicity. Here we compare the effect of a short (4 weeks) or a long (18 weeks) interval between priming and boosting in mice, using a model vaccine formulation based on the chimeric tuberculosis vaccine antigen H56 combined with alum. While no significant difference was observed in serum antigen-specific IgG response and the induction of antigen-specific T follicular helper cells into draining lymph nodes after the two immunization schedules, a longer interval between priming and boosting elicited a higher number of germinal center-B cells and H56-specific antibody-secreting cells and modulated the effector function of reactivated CD4+ T cells. These data show that the scheduling of the booster immunization could affect the immune response elicited by vaccination modulating and improving the immunogenicity of the vaccine.

Impact of SARS-CoV-2 infection on vaccine-induced immune responses over time

“…A longer interval may indeed generate an improved memory formation, albeit at the price of a suboptimal protection during the longer interval between first and second dose in SARS-CoV-2 naïve populations. Although no significant differences in binding antibody titres, a slight elevation in pseudoneutralization titres were found between the 3-4 week and 6-8 week dose interval in SARS-CoV-2 naïve participants, could indicate improved memory formation in the latter 42 . Continued studies are needed to address potential differences in longevity of the immunological memory induced by different prime boost intervals and combinations of various vaccine platforms, as well as the optimal timing of additional vaccine doses.…”

A Higher Antibody Response Is Generated With a 6- to 7-Week (vs Standard) Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Vaccine Dosing Interval

“…We found that compared to the recommended (≤4 week) dosing interval, a 6- to 7-week interval for mRNA vaccines resulted in higher spike-related antibody concentrations. Increased development of germinal center B cells associated with vaccine dosing intervals may explain this observation [ 11 ]. These data may help inform COVID-19 vaccination strategies, especially in settings where vaccine supplies remain constrained.…”

The Rise of Vectored Vaccines: A Legacy of the COVID-19 Global Crisis

“…In the host, in the case of replication-deficient vectors, the transgene is expressed for approximately 24 h, the epitopes are presented via the major histocompatibility complex (MHC), innate T and B cells are recruited, and the vector is rapidly eliminated [13]. Additionally, as the immune system is full of pathways and antigen presentation can take place through several of them, we can expect that a good antigen combined with a good vector can summon the right "soldiers" and trigger robust humoral and cellular responses [92].…”