Response to Letter to the Editor: Post-Vaccination Immunogenicity of BNT162b2 SARS-CoV-2 Vaccine and Its Predictors in Pediatric Inflammatory Bowel Disease

Abstract

Dear Editor, On behalf of our research team, I would like to submit a short response to the Letter to the Editor (“Postvaccination Immunogenicity of COVID-19 Vaccine in Pediatric Inflammatory Bowel Disease.: Comment”)(1) concerning our original article published in JPGN named “Post-Vaccination Immunogenicity of BNT162b2 SARS-CoV-2 Vaccine and Its Predictors in Pediatric Inflammatory Bowel Disease.”(2) We have read with interest the letter submitted by Amnuay Kleebayoon and Viroj Wiwanitkit.(1) In this letter, the authors raise the point that higher post-vaccination levels of anti-spike S2 antibodies in inflammatory bowel disease patients compared to controls could be explained by cross-contamination with “silent COVID-19 infection” in some of the subjects who had no apparent clinical signs at the time of testing. Although this may theoretically be one plausible explanation that we would not be able to rule out (as we did not test all our subjects for SARS-CoV-2 infection along with post-vaccination antibodies), from a statistical point of view we deem unlikely that a silent SARS-CoV-2 infection would appear with different frequency (probability) in each group. Therefore, we consider this unlikely to be a true major factor underlying the difference in the antibody production between inflammatory bowel disease patients and healthy controls. We remain, however, in agreement that the possibility of a cross-contamination with undiagnosed SARS-CoV-2 infections cannot be formally ruled out.