# Demographic and socioeconomic characteristics associated with SARS-CoV-2 reinfection: An observational study

**Authors:** Natasha Nicos Ferreira, Pedro Manoel Marques Garibaldi, Gustavo Jardim Volpe, Bruno Belmonte Martinelli Gomes, Maira Nilson Benatti, Maria Aparecida Alves Leite Dos Santos Almeida, Glenda Renata de Moraes, Dimas Tadeu Covas, Simone Kashima, Rodrigo Tocantins Calado, Benedito Antonio Lopes Fonseca, Marcos Carvalho Borges, Rajiv Sarkar, Rajiv Sarkar, Rajiv Sarkar, Rajiv Sarkar, Rajiv Sarkar

PMC · DOI: 10.1371/journal.pgph.0006103 · 2026-03-10

## TL;DR

This study identifies demographic and socioeconomic factors linked to SARS-CoV-2 reinfection, showing that women and those with poor hygiene or work habits are at higher risk.

## Contribution

The study provides new insights into reinfection risk factors, including gender, hygiene practices, and work status.

## Key findings

- Female sex was associated with a 1.5 times higher risk of reinfection.
- Not practicing hand hygiene increased reinfection risk by 1.35 times.
- Working on-site or from home increased reinfection risk compared to not working.

## Abstract

Since SARS-CoV-2 emergence, risk factors for reinfection have not been totally determined. In this cohort, we analyzed the monthly incidence and outcomes of COVID-19 reinfection and its association with variants of concern, demographic, and socioeconomic factors. An infection case was defined as a positive test for SARS-CoV-2 and reinfection as the presence of a new positive test after 90 days or more of the previous infection. From September 1, 2020, to December 31, 2022, a total of 12,051 cases of COVID-19 were analyzed: 11,129 had one infection, 890 had two infections, and 32 had three infections, yielding a reinfection rate of 7.6%. Female sex was a risk factor for reinfection (RR 1.5, 95% CI 1.23-1.75). A higher risk of reinfection was related to not practicing hand hygiene (RR 1.35, 95% CI 1.14-1.60) and working on-site or from home compared with no work (RR 1.53, 95% CI 1.24-1.87 and RR 3.18, 95% CI 2.02-4.99, respectively). The risk of progressing to moderate or severe disease was higher during the first infection compared with the second (RR 2.12, 95% CI 1.34-3.34). Patients with two or three infections were older than those with one, with a mean age of 75.5 ± 17.3 and 59.6 ± 19.1 years old, respectively (p < 0.002). Our results underscore the importance of targeted public health campaigns and preventive measures for specific demographic groups.

## Linked entities

- **Diseases:** SARS-CoV-2 (MONDO:0100096), COVID-19 (MONDO:0100096)

## Full-text entities

- **Genes:** ORF1ab (ORF1a polyprotein;ORF1ab polyprotein) [NCBI Gene 43740578], E (envelope protein) [NCBI Gene 43740570], N (nucleocapsid phosphoprotein) [NCBI Gene 43740575]
- **Diseases:** re-infection (MESH:D000084063), sore throat (MESH:D010612), death (MESH:D003643), hypertension (MESH:D006973), infection (MESH:D007239), COVID-19 (MESH:D000086382), nasal congestion (MESH:D009668), cough (MESH:D003371), muscle pain (MESH:D063806), infectious disease (MESH:D003141), headache (MESH:D006261), dysgeusia (MESH:D004408), dyspnea (MESH:D004417), diabetes (MESH:D003920), nausea (MESH:D009325), coryza (MESH:D003139), fatigue (MESH:D005221), diarrhea (MESH:D003967), fever (MESH:D005334), anosmia (MESH:D000857), vomiting (MESH:D014839)
- **Chemicals:** PGPH-D-24-03019 (-)
- **Species:** Homo sapiens (human, species) [taxon 9606], Severe acute respiratory syndrome coronavirus 2 (no rank) [taxon 2697049]

## Figures

5 figures with captions in the complete paper: https://tomesphere.com/paper/PMC12974802/full.md

---
Source: https://tomesphere.com/paper/PMC12974802