Longitudinal study comparing IgG antibodies induced by heterologous prime­boost COVID­19 vaccine

ABSTRACT: Vaccines are critical cost­effective tools to control the COVID­19 pandemic. The heterologous prime­boost vaccination has been used by many countries to overcome supply issues, so the effectiveness and safety of this strategy need to be better clarified. This study aims to verify the effect of heterologous prime­boost COVID­19 vaccination on healthcare professionals from Dante Pazzanese Hospital in Brazil. It was performed serological assays of vaccinated individuals after 2­dose of CoronaVac (Sinovac; n = 89) or ChAdOx1 nCoV­19 (Oxford­AstraZeneca; n = 166) followed by a BNT162b2 booster (Pfizer­BioNTech; n = 255). The serum antibodies anti­S (spike), anti­N (nucleocapsid), and anti­RBD (receptor binding domain) were assessed by enzyme­linked immunosorbent assay. The heterologous booster dose induced a 10­fold higher anti­Spike antibody regardless of the 2­dose of a prime vaccine. It was strikingly observed that BNT162b2 enhanced levels of anti­spike antibodies, even in those individuals who did not previously respond to the 2­dose of CoronaVac. In conclusion, the heterologous scheme of vaccination using mRNA as a booster vaccine efficiently enhanced the antibody response against SARS­CoV­2, especially benefiting those elderly who were seronegative with a virus­inactivated vaccine.

Longitudinal study comparing IgG antibodies induced by heterologous prime-boost COVID-19 vaccine.

Vaccines are critical cost-effective tools to control the COVID-19 pandemic. The heterologous prime-boost vaccination has been used by many countries to overcome supply issues, so the effectiveness and safety of this strategy need to be better clarified. This study aims to verify the effect of heterologous prime-boost COVID-19 vaccination on healthcare professionals from Dante Pazzanese Hospital in Brazil. It was performed serological assays of vaccinated individuals after 2-dose of CoronaVac (Sinovac; n = 89) or ChAdOx1 nCoV-19 (Oxford-AstraZeneca; n = 166) followed by a BNT162b2 booster (Pfizer-BioNTech; n = 255). The serum antibodies anti-S (spike), anti-N (nucleocapsid), and anti-RBD (receptor binding domain) were assessed by enzyme-linked immunosorbent assay. The heterologous booster dose induced a 10-fold higher anti-Spike antibody regardless of the 2-dose of a prime vaccine. It was strikingly observed that BNT162b2 enhanced levels of anti-spike antibodies, even in those individuals who did not previously respond to the 2-dose of CoronaVac. In conclusion, the heterologous scheme of vaccination using mRNA as a booster vaccine efficiently enhanced the antibody response against SARS-CoV-2, especially benefiting those elderly who were seronegative with a virus-inactivated vaccine.

Sequential IgG antibody monitoring for virus­inactivated and adenovirus­vectored COVID­19 vaccine in Brazilian health care workers

Vaccination certainly is the best way to fight against the COVID­19 pandemic. In this study, the seroconversion effectiveness of two vaccines against severe acute respiratory syndrome coronavirus 2 was assessed in healthcare workers: virus­inactivated CoronaVac (CV, n= 303), and adenovirus­vectored Oxford­AstraZeneca (AZ, n= 447). The immunoglobulin G (IgG) antibodies anti­spike glycoprotein and anti­nucleocapsid protein were assessed by enzyme­linked immunosorbent assay at the time before vaccination (T1), before the second dose (T2), and 30 days after the second dose (T3). Of all individuals vaccinated with AZ, 100% (n= 447) exhibited seroconversion, compared to 91% (n= 276) that were given CV vaccine. Among individuals who did not respond to the CV, only three individuals showed a significant increase in the antibody level 4 months later the booster dose. A lower seroconversion rate was observed in elders immunized with the CV vaccine probably due to the natural immune senescence, or peculiarity of this vaccine. The AZ vaccine induced a higher humoral response; however, more common side effects were also observed. Nonvaccinated convalescent individuals revealed a similar rate of anti­spike IgG to individuals that were given two doses of CV vaccine, which suggests that only a one­shot COVID­19 vaccine could produce an effective immune response in convalescents.