key: cord-0993346-b2pi5cf9
authors: Brnjarchevska Blazhevska, Teodora; Babačić, Haris; Sibinovska, Olgica; Dobrevski, Boban; Kirijas, Meri; Milanovski, Gorjan; Arsov, Todor; Petlichkovski, Aleksandar
title: A single dose of BNT162b2 vaccine elicits strong humoral response in SARS‐CoV‐2 seropositive individuals
date: 2021-08-21
journal: Allergy
DOI: 10.1111/all.15047
sha: c9085084be4c13ad57f766fe4e80c433b14b4c2d
doc_id: 993346
cord_uid: b2pi5cf9

nan

To the Editor The high demand for COVID-19 vaccines, combined with a significant lack of supply, leaves smaller and developing countries behind in mass immunization. This prompts the question whether administering a single vaccine dose in SARS-CoV-2 seropositive individuals could be a method for rationing available vaccine doses.

We report results from a prospective study on Macedonian healthcare workers who received two doses of the Pfizer/BioNTech BNT162b2 mRNA vaccine, comparing antibody titres and frequency of side effects after vaccine administration between individuals who were SARS-CoV-2 seropositive (SeroPOS group) and seronegative (SeroNEG group) prior to immunization. The study included 226 participants recruited through convenience sampling, of whom 41

were SeroPOS (73.17% female; mean age 43 years, SD: 10.571), and 185 were SeroNEG (68.11% female, mean age 46 years, SD: 10.523).

Appendix (Table S1 ). Blood samples were collected 18-21 days after the first vaccine dose and 25-28 days after the second dose. Baseline antibody levels were obtained from patient records. All participants gave blood samples after the first dose and filed a questionnaire for side effects, and 189 participants (83.63%) returned for assessment four weeks after the second dose. Serological testing was performed using the commercially available quantitative CLIA anti-SARS-CoV-2 RBD kit (Snibe, Shenzhen, China), 1 which targets the S1 subunit of Table S2 ). The vast majority of the study participants reported at least one side effect after the first dose (91.15%, Figure 1C ), mostly minor local pain (69.47%). A higher proportion of study participants reported at least one side effect after the second dose (97.35%, Figure 1D 

Cyril and Methodius University in Skopje, Faculty of Medicine-Skopje, Institute for Immunobiology and Human Genetics, 50. Divizija 6a

SARS-CoV-2 serosurvey in health care workers of the Veneto region

Antibody responses to the BNT162b2 mRNA vaccine in individuals previously infected with SARS-CoV-2

Antibody responses in seropositive persons after a single dose of SARS-CoV-2 mRNA vaccine

Binding and neutralization antibody titers after a single vaccine dose in health care workers previously infected with SARS-CoV-2

Effect of previous SARS-CoV-2 infection on humoral and T-cell responses to single-dose BNT162b2 vaccine