Good Immunogenicity of Delayed Second Dose of BNT162b2 Vaccine in Individuals with Acute Allergic-like Reactions after the First Dose

We assessed SARS-CoV-2 anti-spike immunoglobulin G (anti-S-IgG) levels among healthcare workers (HCWs) after BNT162b2 vaccination. The anti-S-IgG titers of study participants were measured every three months, a week before, and three weeks after each vaccination. This study compared the short-term immune response to the second vaccination in four HCWs who received the first two doses six months apart (due to acute allergic-like adverse events after the first dose), with that of six HCWs who received the first two doses three weeks apart, according to the standard schedule. The four HCWs who experienced acute allergic-like adverse events after the first vaccination took antihistamines before the second vaccination. None of them experienced an allergic-like reaction after the second vaccination, and the short-term immune response to the second vaccination was similar in both groups.