Immediate reinfection with Omicron variant after clearance of a previous SARS-CoV-2 infection

Antonella Mencacci; Alessio Gili; Barbara Camilloni; Giulia Bicchieraro; Roberta Spaccapelo; Carla Bietta; Fabrizio Stracci

doi:10.1016/j.jiph.2022.07.013

Immediate reinfection with Omicron variant after clearance of a previous SARS-CoV-2 infection

J Infect Public Health. 2022 Sep;15(9):983-985. doi: 10.1016/j.jiph.2022.07.013. Epub 2022 Jul 28.

Authors

Antonella Mencacci¹, Alessio Gili², Barbara Camilloni³, Giulia Bicchieraro³, Roberta Spaccapelo³, Carla Bietta⁴, Fabrizio Stracci⁵

Affiliations

¹ Microbiology and Clinical Microbiology, Department of Medicine and Surgery, University of Perugia, Perugia, Italy. Electronic address: antonella.mencacci@unipg.it.
² Public Health Section, Department of Medicine and Surgery, University of Perugia, Perugia, Italy.
³ Microbiology and Clinical Microbiology, Department of Medicine and Surgery, University of Perugia, Perugia, Italy.
⁴ Epidemiology Unit, Department of Preventive Medicine, Local Health Unit 1, Umbria region, Italy.
⁵ Public Health Section, Department of Medicine and Surgery, University of Perugia, Perugia, Italy. Electronic address: fabrizio.stracci@unipg.it.

Abstract

SARS-CoV-2 Omicron variant is spreading worldwide, causing unprecedented epidemic peaks due to its transmissibility and immune evasion. We searched in the archive of the Regional Microbiology Laboratory (Umbria, Italy) for immediate reinfection (i.e. infection occurring 25-60 days from primary infection) among 454,764 RT-PCR tests from 261,217 individuals. Lineage heterogeneity was assessed by S gene target failure phenomenon or whole genome sequencing. We found that BA.1 Omicron variant may cause immediate reinfection of patients just recovered from Delta infection. Immediate reinfection was not observed for any other combination of variants, including Delta over Alpha variant and BA.2 over BA.1 Omicron lineage.

Keywords: COVID-19; Delta; Omicron; Reinfection; SARS-CoV-2.

MeSH terms

COVID-19*
Humans
Italy / epidemiology
SARS-CoV-2 / genetics

Supplementary concepts

SARS-CoV-2 variants