Antibody responses to the BBV152 vaccine in individuals previously infected with SARS-CoV-2: A pilot study

Abstract

Background & objectives: Vaccination against SARS-CoV-2 is a recommendation from the World Health Organization as the foremost preference in the current situation to control the COVID-19 pandemic. BBV152 is one of the approved vaccines against SARS-CoV-2 in India. In this study, we determined SARS-CoV-2-specific antibody levels at day 0 (baseline, before vaccination), day 28 ± 2 post-first dose (month 1) and day 56 ± 2 post-first dose (month 2) of BBV152 whole-virion-inactivated SARS-CoV-2 recipients, and compared the antibody responses of individuals with confirmed pre-vaccination SARS-CoV-2 infection to those individuals without prior evidence of infection.

Methods: Blood samples were collected from 114 healthcare professionals and frontline workers who received BBV152 vaccine from February to May & June 2021. Prior infection with SARS-CoV-2 was determined at baseline. Serum samples were used to estimate SARS-CoV-2 nucleoprotein-specific IgG [IgG (N)], spike protein-specific IgG [IgG (S)] and neutralizing antibodies (NAb).

Results: Participants with previous SARS-CoV-2 infection after a single vaccine dose elicited IgG (N) and IgG (S) antibody levels along with NAb binding inhibition responses levels were similar to infection-naïve vaccinated participants who had taken two doses of vaccine.

Interpretation & conclusions: Our preliminary data suggested that a single dose of BBV152-induced humoral immunity in previously infected individuals was equivalent to two doses of the vaccine in infection-naïve individuals. However, these findings need to be confirmed with large sized cohort studies.

Keywords: BBV152; COVID-19 vaccine; IgG; SARS-CoV-2; neutralizing antibody.

Fig. 1

Outline of participant categorization. Blood samples were collected from COVID-19 vaccine BBV152 vaccinated individuals (n=114) during day 0 (baseline, before vaccination), day 28±2 post-first dose (month 1) and day 56±2 post-first dose (month 2).

Fig. 2

SARS-CoV-2 antibody response to whole-virion–inactivated BBV152 vaccine in individuals with and without prior SARS-CoV-2 infection. The serum levels of (A) SARS-CoV-2 (N) protein, (B) SARS-CoV-2 (S) protein and (C) SARS-CoV-2 neutralizing antibodies (NAb) were measured in no prior infection (n=84) and prior infection (n=30) individuals. Box plots display the median values with the interquartile range (lower and upper hinge). The data are also represented as scatter plots with each circle representing a single individual. The values plotted on y-axis represent log-median values. P *<0.05, ***<0.001 compared to those with no prior infection.