摘要
Inducing durable and effective immunity against severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)via vaccination is essential to combat the current pandemic of coronavirus disease 2019(COVID-19).It has been noticed that the strength of anti-COVID-19 vaccination-induced immunity fades over time,which calls for an additional vaccination regime,as known as booster immunization,to restore immunity among previously vaccinated populations.Here we report a pilot open-label trial of a third dose of BBIBP-CorV,an inactivated SARS-CoV-2 vaccine(Vero cell),on 136 participants aged between 18 to 63 years.Safety and immunogenicity in terms of neutralizing antibody titers and cytokine/chemokine responses were analyzed as the main endpoint until day 28.While systemic reactogenicity was either absent or mild,SARS-CoV-2-specific neutralizing antibody titers rapidly arose in all participants within 4 weeks,surpassing the peak antibody titers elicited by the initial two-dose immunization regime.Broad increases of cellular immunity-associated cytokines and chemokines were also detected in the majority of participants after the third vaccination.Furthermore,in an exploratory study,a newly developed recombinant protein vaccine,NVSI-06-08(CHO Cells),was found to be safe and even more effective than BBIBP-CorV in eliciting humoral immune responses in BBIBP-CorV-primed individuals.Together,these results indicate that a third immunization schedule with either homologous or heterologous vaccine showed favorable safety profiles and restored potent SARS-CoV-2-specific immunity,providing support for further trials of booster vaccination in larger populations.
基金
supported by the National Program on Key Research Project of China(Nos.2020YFA0707500,2016YFD0500301,2017YFC0840300,2020YFC0842100)
National Mega projects of China for Major Infectious Diseases(No.2016ZX10004001-003)
National Mega Projects of China for New Drug Creation(No.2018ZX09734-004)
Beijing Science and Technology Plan(No.Z201100005420014).