Respiratory Syncytial Virus, Influenza and SARS-CoV-2 in Homeless People from Urban Shelters: A Systematic Review and Meta-Analysis (2023)

Abstract

Homeless people (HP) are disproportionally affected by respiratory disorders, including pneumococcal and mycobacterial infections. On the contrary, more limited evidence has been previously gathered on influenza and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and very little is known about the occurrence of human respiratory syncytial virus (RSV), a common cause of respiratory tract infections among children and the elderly. The present systematic review was designed to collect available evidence about RSV, influenza and SARS-CoV-2 infections in HP, focusing on those from urban homeless shelters. Three medical databases (PubMed, Embase and Scopus) and the preprint repository medRxiv.org were therefore searched for eligible observational studies published up to 30 December 2023, and the collected cases were pooled in a random-effects model. Heterogeneity was assessed using the I² statistics. Reporting bias was assessed by funnel plots and a regression analysis. Overall, 31 studies were retrieved, and of them, 17 reported on the point prevalence of respiratory pathogens, with pooled estimates of 4.91 cases per 1000 HP (95%CI: 2.46 to 9.80) for RSV, 3.47 per 1000 HP for influenza and 40.21 cases per 1000 HP (95%CI: 14.66 to 105.55) for SARS-CoV-2. Incidence estimates were calculated from 12 studies, and SARS-CoV-2 was characterized by the highest occurrence (9.58 diagnoses per 1000 persons-months, 95%CI: 3.00 to 16.16), followed by influenza (6.07, 95%CI: 0.00 to 15.06) and RSV (1.71, 95%CI: 0.00 to 4.13). Only four studies reported on the outcome of viral infections in HP: the assessed pathogens were associated with a high likelihood of hospitalization, while high rates of recurrence and eventual deaths were reported in cases of RSV infections. In summary, RSV, influenza and SARS-CoV-2 infections were documented in HP from urban shelters, and their potential outcomes stress the importance of specifically tailored preventive strategies.

Keywords: RSV; SARS-CoV-2; differential diagnosis; homelessness; influenza; viral pneumonia.

Figure A1

Forest plot for prevalence studies on RSV (a), influenza (b) and SARS-CoV-2 infections (c) among homeless people. All estimates are reported in cases per 1000 people [4,5,6,17,18,42,98,99,100,101,102,103,104,105,106,107,108].

Figure A1

Forest plot for prevalence studies on RSV (a), influenza (b) and SARS-CoV-2 infections (c) among homeless people. All estimates are reported in cases per 1000 people [4,5,6,17,18,42,98,99,100,101,102,103,104,105,106,107,108].

Figure A2

Forest plot for incidence studies on RSV (a), influenza (b) and SARS-CoV-2 infections (c) among homeless people. All estimates are reported in cases per 1000 person-months [19,20,21,44,109,110,111,112,113,114,115,116].

Figure A2

Forest plot for incidence studies on RSV (a), influenza (b) and SARS-CoV-2 infections (c) among homeless people. All estimates are reported in cases per 1000 person-months [19,20,21,44,109,110,111,112,113,114,115,116].

Figure A3

Sensitivity analysis on prevalence studies on RSV (a), influenza (b) and SARS-CoV-2 (c) in homeless people. Analyses were performed through the approach of removing a single study at a time [4,5,6,17,18,42,98,99,100,101,102,103,104,105,106,107,108] (Distinctive series within the same study are noted with progressive letter).

Figure A3

Sensitivity analysis on prevalence studies on RSV (a), influenza (b) and SARS-CoV-2 (c) in homeless people. Analyses were performed through the approach of removing a single study at a time [4,5,6,17,18,42,98,99,100,101,102,103,104,105,106,107,108] (Distinctive series within the same study are noted with progressive letter).

Figure A4

Sensitivity analysis on incidence studies on RSV (a), influenza (b) and SARS-CoV-2 (c) in homeless people. Analyses were performed through the approach of removing a single study at a time [19,20,21,44,109,110,111,112,113,114,115,116].

Figure A4

Sensitivity analysis on incidence studies on RSV (a), influenza (b) and SARS-CoV-2 (c) in homeless people. Analyses were performed through the approach of removing a single study at a time [19,20,21,44,109,110,111,112,113,114,115,116].

Figure A5

Funnel plots for studies on prevalence rates for respiratory pathogens included in the analyses, (a) respiratory syncytial virus (RSV); (c) influenza; (e) SARS-CoV-2, and corresponding radial plots (RSV, (b); influenza, (d), SARS-CoV-2, (f) [4,5,6,17,18,42,98,99,100,101,102,103,104,105,106,107,108].

Figure A6

Funnel plots for studies on incidence rates for respiratory pathogens included in the analyses, (a) respiratory syncytial virus (RSV); (c) influenza; (e) SARS-CoV-2, and corresponding radial plots (RSV, (b); influenza, (d), SARS-CoV-2, (f) [19,20,21,44,109,110,111,112,113,114,115,116].

Figure 1

Flowchart of included studies.

Figure 2

Forest plot reporting Risk Ratios (RRs) with their corresponding 95% confidence intervals (95%CI) for the occurrence of positive cases among the sampled homeless people: subfigure (a), prevalence estimates, whole of assessed timeframe; subfigure (b): prevalence estimates, post-pandemic studies (data retrieved starting with January 2020) are compared to pre-pandemic studies (data collected before January 2020) [4,5,6,17,18,42,98,99,100,101,102,103,104,105,106,107,108]; subfigure (c): positive samples from incidence studies, positive rates for influenza are considered the reference group [19,20,21,44,109,110,111,112,113,114,115,116].

Figure 3

Summary of the risk of bias (ROB) estimates for the observational studies [89,119]. Analyses were performed according to the National Toxicology Program’s (NTP) Office of Health Assessment and Translation (OHAT) handbook and respective risk of bias (ROB), tool including all the retrieved studies (N. = 31, (a)), and the settings of the studies, i.e., prevalence studies (N. = 17, (b)) [4,5,6,17,18,42,98,99,100,101,102,103,104,105,106,107,108] and incidence studies (N. = 12; (c)) [19,20,21,44,109,110,111,112,113,114,115,116].

Figure 4

Forest plots reporting the odds of developing RSV (A) and SARS-CoV-2 infections (B) among homeless people compared to influenza in the same studies [4,5,6,17,18,42,98,99,100,101,102,103,104,105,106,107,108] (Distinctive series within the same study are noted with progressive letter).