Comparison of immune responses induced by two or three doses of an alum-adjuvanted inactivated SARS-CoV-2 vaccine in mice.
J Med Virol
; 94(5): 2250-2258, 2022 05.
Article
in English
| MEDLINE | ID: covidwho-1664418
ABSTRACT
Waning antibodies and rapidly emerging variants are challenges for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine development. Adjusting existing immunization schedules and further boosting strategies are under consideration. Here, the immune responses induced by an alum-adjuvanted inactivated SARS-CoV-2 vaccine in mice were compared among immunization schedules with two or three doses. For the two-dose schedule, a 0-28-day schedule induced 5-fold stronger spike-specific IgG responses than a 0-14-day schedule, with only a slight elevation of spike-specific cellular immunity 14 days after the last immunization. A third homologous boost 2 or 5 months after the second dose for the 0-28-day schedule slightly strengthened humoral responses (1.3-fold for the 0-1-3-month schedule, and 1.8-fold for the 0-1-6-month schedule) 14 days after the last immunization. Additionally, a third homologous boost (especially with the 0-1-3-month schedule) induced significantly stronger cell-mediated immunity than both two-dose immunization schedules for all indexes tested, with a response similar to that induced by a one-dose heterologous boost with BNT162b2 in clinical trials, according to cellular immunity analysis (1.5-fold). These T cell responses were Th2 oriented, with good CD4+ and CD8+ memory. These results may offer clues for applying a homologous boosting strategy for alum-adjuvanted inactivated SARS-CoV-2 vaccines.
Keywords
Full text:
Available
Collection:
International databases
Database:
MEDLINE
Main subject:
COVID-19 Vaccines
/
COVID-19
Type of study:
Prognostic study
Topics:
Vaccines
/
Variants
Limits:
Animals
/
Humans
Language:
English
Journal:
J Med Virol
Year:
2022
Document Type:
Article
Affiliation country:
Jmv.27637
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