Hybrid Immunity in a Mozambican Cohort After 1 or 2 Doses of the BBIBP-CorV Vaccine.
More than half of the BBIBP-CorV vaccines, outside of Pacific Asia, were distributed in Africa. Nevertheless, there are limited data on the immunogenicity of BBIBP-CorV from Africa. We compared the antibody response, after 1 and 2 doses of the BBIBP-CorV vaccine, in individuals seropositive or seronegative to severe acute respiratory syndrome coronavirus 2 prior to vaccination.
From March to May 2021, blood samples were obtained at first and second doses of the BBIBP-CorV, and 2 weeks later. Antibody titers against the full-length spike, receptor binding domain and nucleocapsid protein (anti-NC) of severe acute respiratory syndrome coronavirus 2 were measured. Pseudovirus neutralization assays and antibody-dependent cellular cytotoxicity (ADCC) against the D614G, BA.2, and BA.4 variants were also evaluated.
At the second dose, the immunoglobulin G titers for full-length spike and anti-nucleocapsid protein, the ADCC against BA-2, and the neutralizing activity against the D614G and BA.2 were higher in individuals seropositive to any of the epitopes at the first dose (n = 26) compared to the levels observed 2 weeks later in the seronegative group (n = 25). We did not observe an increase on magnitude of binding antibodies, ADCC, and neutralizing activities, in those seropositive, after the second homologous dose of the BBIBP-CorV vaccine.
We suggest that 1 dose of the BBIBP-CorV vaccine in seropositive individuals induced better antibodies response including against variant of concerns compared to that observed after 2 doses in seronegative individuals. A further homologous dose of the BBIBP-CorV vaccine, in those who are seropositive, does not improve the antibody response observed after the first dose.
From March to May 2021, blood samples were obtained at first and second doses of the BBIBP-CorV, and 2 weeks later. Antibody titers against the full-length spike, receptor binding domain and nucleocapsid protein (anti-NC) of severe acute respiratory syndrome coronavirus 2 were measured. Pseudovirus neutralization assays and antibody-dependent cellular cytotoxicity (ADCC) against the D614G, BA.2, and BA.4 variants were also evaluated.
At the second dose, the immunoglobulin G titers for full-length spike and anti-nucleocapsid protein, the ADCC against BA-2, and the neutralizing activity against the D614G and BA.2 were higher in individuals seropositive to any of the epitopes at the first dose (n = 26) compared to the levels observed 2 weeks later in the seronegative group (n = 25). We did not observe an increase on magnitude of binding antibodies, ADCC, and neutralizing activities, in those seropositive, after the second homologous dose of the BBIBP-CorV vaccine.
We suggest that 1 dose of the BBIBP-CorV vaccine in seropositive individuals induced better antibodies response including against variant of concerns compared to that observed after 2 doses in seronegative individuals. A further homologous dose of the BBIBP-CorV vaccine, in those who are seropositive, does not improve the antibody response observed after the first dose.
Authors
Chissumba Chissumba, Kwatra Kwatra, Ramgi Ramgi, Enosse Enosse, Sigaúque Sigaúque, Khosa Khosa, Viegas Viegas, Bule Bule, Langa Langa, Dhar Dhar, Mukendi Mukendi, Langa Langa, Sevene Sevene, Hermanus Hermanus, Manamela Manamela, Richardson Richardson, Moore Moore, Madhi Madhi, Jani Jani,
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