Antibody and T Cell Responses against SARS-CoV-2 Elicited by the Third Dose of BBIBP-CorV (Sinopharm) and BNT162b2 (Pfizer-BioNTech) Vaccines Using a Homologous or Heterologous Booster Vaccination Strategy

Abstract

In the present study, antibody and T cell-mediated immune responses elicited by BBIBP-CorV and BNT162b2 vaccines were compared 6 months after the two-dose immunization of healthy individuals. Additionally, antibody and T cell responses after the third dose of BBIBP-CorV or BNT162b2 were compared using a homologous or heterologous vaccination strategy. The third dose was consistently administered 6 months after the second dose. Six months following the two-dose vaccination, the cumulative IFNγ-positive T cell response was almost identical in participants immunized with either two doses of BNT162b2 or BBIBP-CorV vaccines; however, significant differences were revealed regarding humoral immunity: the two-dose BNT162b2 vaccine maintained a significantly higher antireceptor-binding domain (RBD) IgG, anti-spike (S1/S2) IgG, and IgA antibody levels. The BNT162b2 + BNT162b2 + BBIBP-CorV vaccine series elicited significantly lower anti-RBD IgG and anti-S1/S2 IgG levels than three doses of BNT162b2, while the anti-S IgA level was equally negligible in both groups. Importantly, the cumulative IFNγ-positive T cell response was highly similar in both groups. Surprisingly, the BBIBP-CorV + BBIBP-CorV + BNT162b2 vaccination series provided a much higher cumulative IFNγ-positive T cell response than that elicited by three doses of BNT162b2; moreover, the levels of anti-RBD IgG and anti-S IgA were almost identical. Only the mean anti-S1/S2 IgG levels were higher after receiving three mRNA vaccines. Based on these data, we can conclude that administering a third dose of BNT162b2 after two doses of BBIBP-CorV is an effective strategy to significantly enhance both humoral and T cell-mediated immune response, and its effectiveness is comparable to that of three BNT162b2 vaccines.

Effectiveness and waning of protection with different SARS-CoV-2 primary and booster vaccines during the Delta pandemic wave in 2021 in Hungary (HUN-VE 3 study)

“…In line with these observations, our study also demonstrated very high effectiveness against infection with the Delta variant for mRNA booster vaccines during the first 4 months irrespective of the type of the primary immunization, and very high, almost 100% effectiveness against Covid-19 related hospitalization and death. Our results harmonized and partially explained by a recently published Hungarian study, where administering a third dose of BNT162b2 (Pfizer-BioNTech) vaccine following two doses of Sinopharm vaccines provided a significantly enhance both humoral and T cell-mediated immune response, and its effectiveness was comparable to three doses of BNT162b2 vaccines (33).…”

Safety and Immunogenicity of Inactivated Bacillus subtilis Spores as a Heterologous Antibody Booster for COVID-19 Vaccines

“…The average time durations between the second dose and this booster study in the booster and placebo groups were 8.67 ± 2.00 and 7.86 ± 1.86 months, respectively, leaving no significant difference between the two groups (two-sample t -test, p > 0.05). Several studies reported that the neutralizing antibody level declined over time and reached a stabilization phase at low levels (~60% for BNT162b2 and 15% for BBIBP), from 6 months after the second dose of the primary vaccination cycle [ 26 ]. The starting date of the booster study was thus chosen using at least 6 months as the criterion.…”

Immunogenicity Following Two Doses of the BBIBP-CorV Vaccine and a Third Booster Dose with a Viral Vector and mRNA COVID-19 Vaccines against Delta and Omicron Variants in Prime Immunized Adults with Two Doses of the BBIBP-CorV Vaccine

“…Studies of the third dose of COVID-19 vaccination reported the effectiveness of reducing risk in symptomatic infection and hospitalization rates compared to two doses of vaccination [ 15 , 19 , 22 ]. Therefore, for the general population, vaccination is necessary.…”

“…Therefore, for the general population, vaccination is necessary. Furthermore, heterologous booster doses (two prime doses with inactive or viral vector vaccine and a third dose with an mRNA vaccine) appear to induce higher levels of immune response than homologous booster doses do, suggesting that heterologous immunization could be considered an alternative to homologous booster doses for immunization programs [ 22 , 32 , 33 ]. To assess the immunogenicity of a booster vaccination, our study found that a third booster dose with heterologous booster immunization of AZD1222, BNT162b2, and mRNA-1273 showed a high titer of total RBD Ig and anti-RBD IgG compared to that before the third booster.…”

“…Antibody and T-cell responses against SARS-CoV-2 in two-dose BBIBP-CorV-primed individuals after the administration of the third dose of BNT162b2 have achieved a significant increase in both humoral and T-cell-mediated immune response [ 22 ]. The immunogenicity after a booster dose with a viral vector or other mRNA vaccine (mRNA1273) in BBIBP-CorV-primed individuals is limited.…”