Antibody Response of BNT162b2 and CoronaVac Platforms in Recovered Individuals Previously Infected by COVID-19 against SARS-CoV-2 Wild Type and Delta Variant

Abstract

Vaccinating recovered patients previously infected by COVID-19 with mRNA vaccines to boost their immune response against wild-type viruses (WT), we aimed to investigate whether vaccine platform and time of vaccination affect immunogenicity against the SARS-CoV-2 WT and Delta variant (DV). Convalescent patients infected by COVID-19 were recruited and received one booster dose of the BNT162b2 (PC-B) or CoronaVac (PC-C) vaccines, while SARS-CoV-2 naïve subjects received two doses of the BNT162b2 (CN-B) or CoronaVac (CN-C) vaccines. The neutralizing antibody in sera against the WT and DV was determined with live virus neutralization assay (vMN). The vMN geometric mean titre (GMT) against WT in recovered individuals previously infected by COVID-19 reduced significantly from 60.0 (95% confidence interval (CI), 46.5–77.4) to 33.9 (95% CI, 26.3–43.7) at 6 months post recovery. In the PC-B group, the BNT162b2 vaccine enhanced antibody response against WT and DV, with 22.3-fold and 20.4-fold increases, respectively. The PC-C group also showed 1.8-fold and 2.2-fold increases for WT and DV, respectively, after receiving the CoronaVac vaccine. There was a 10.6-fold increase in GMT in the CN-B group and a 1.3-fold increase in the CN-C group against DV after full vaccination. In both the PC-B and PC-C groups, there was no difference between GMT against WT and DV after vaccination. Subjects in the CN-B and CN-C groups showed inferior GMT against DV compared with GMT against WT after vaccination. In this study, one booster shot effectively enhanced the pre-existing neutralizing activity against WT and DV in recovered subjects.

Immunogenicity of a Heterologous Prime-Boost COVID-19 Vaccination with mRNA and Inactivated Virus Vaccines Compared with Homologous Vaccination Strategy against SARS-CoV-2 Variants

“…In one clinical study, Vasileiou et al reported that the effectiveness of primer-dose BNT162b2 was 85% at day 28-34 post-vaccination and then dropped to a level of 64% after 42 days post-vaccination [22]. Furthermore, from our previous study, the neutralizing activity in recovered patients with previous COVID-19 infection decreased significantly at week 6 after discharge [23]. Thus, the antibody response on day 56 might be lower than on day 28 in healthy individuals who have just received one dose of BNT162b2.…”

Boosting of serum neutralizing activity against the Omicron variant among recovered COVID-19 patients by BNT162b2 and CoronaVac vaccines

“…This is consistent with previous studies which showed a weaker NAb response among recipients of inactivated vaccines compared to mRNA vaccines. 19 , 24 , 32 , 39 , 40 , 47 However, we did not assess the T cell response, which may be important for the prevention of severe disease. Gilbert et al.…”

“…Some patients in the vaccinated cohort were included in our previous study. 32 Under elimination strategy, all individuals with laboratory-confirmed COVID-19 are isolated in hospitals. For asymptomatic patients, the day of hospitalization was used as the date of symptom onset.…”

Kinetics of the Neutralizing and Spike SARS-CoV-2 Antibodies following the Sinovac Inactivated Virus Vaccine Compared to the Pfizer mRNA Vaccine in Singapore

“…In another study of 288 participants [ 18 ], 99.3% of mRNA vaccine recipients were positive for IgG (VIDAS, Biomerieux Inc., Hazelwood, MO, USA) 6 weeks after the second dose of the vaccine, with mean titers of 515.5 BAU/mL, but only 85.7% of inactivated virus vaccine recipients were seropositive, with lower mean S-Ab titers around three-fold less than the titers of the mRNA vaccine group (170 BAU/mL). Even in patients with previous COVID-19 infection, a post-infection booster of mRNA vaccine (BNT162b2) caused 20.4–22.3-fold increases in virus neutralization titers, while the inactivated vaccine only resulted in a 1.8–2.2-fold increase [ 19 ]. Our findings are also supported by studies of patients who received heterologous dosing regimens [ 20 ], where a third dose of mRNA vaccine in patients who already received two doses of inactivated virus vaccine elicited a much more robust anti-receptor binding domain antibodies 14 days after inoculation (third dose inactivated virus vaccine: antibody geometric mean titer 1073 U/mL, third dose mRNA vaccine: antibody geometric mean titer 20,787 U/mL).…”