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Meta-Analysis
. 2022 Dec:130:63-94.
doi: 10.1016/j.jhin.2022.09.007. Epub 2022 Sep 14.

Viral cultures for assessing fomite transmission of SARS-CoV-2: a systematic review and meta-analysis

I J Onakpoya  1 , C J Heneghan  2 , E A Spencer  2 , J Brassey  3 , E C Rosca  4 , S Maltoni  5 , A Plüddemann  2 , D H Evans  6 , J M Conly  7 , T Jefferson  2
Affiliations
Meta-Analysis

Viral cultures for assessing fomite transmission of SARS-CoV-2: a systematic review and meta-analysis

I J Onakpoya et al. J Hosp Infect. 2022 Dec.

Abstract

Background: The role of fomites in the transmission of SARS-CoV-2 is unclear.

Aim: To assess whether SARS-CoV-2 can be transmitted through fomites, using evidence from viral culture studies.

Methods: Searches were conducted in the World Health Organization COVID-19 Database, PubMed, LitCovid, medRxiv, and Google Scholar to December 31st, 2021. Studies that investigated fomite transmission and performed viral culture to assess the cytopathic effect (CPE) of positive fomite samples and confirmation of SARS-CoV-2 as the cause of the CPE were included. The risk of bias using a checklist modified from the modified Quality Assessment of Diagnostic Accuracy Studies - 2 (QUADAS-2) criteria was assessed.

Findings: Twenty-three studies were included. The overall risk of bias was moderate. Five studies demonstrated replication-competent virus from fomite cultures and three used genome sequencing to match fomite samples with human clinical specimens. The mean cycle threshold (CT) of samples with positive viral culture was significantly lower compared with cultured samples that returned negative results (standardized mean difference: -1.45; 95% confidence interval (CI): -2.00 to -0.90; I2 = 0%; P < 0.00001). The likelihood of isolating replication-competent virus was significantly greater when CT was <30 (relative risk: 3.10; 95% CI: 1.32 to 7.31; I2 = 71%; P = 0.01). Infectious specimens were mostly detected within seven days of symptom onset. One study showed possible transmission of SARS-CoV-2 from fomites to humans.

Conclusion: The evidence from published studies suggests that replication-competent SARS-CoV-2 is present on fomites. Replication-competent SARS-CoV-2 is significantly more likely when the PCR CT for clinical specimens and fomite samples is <30. Further studies should investigate the duration of infectiousness of SARS-CoV-2 and the frequency of transmission from fomites.

Keywords: COVID-19; Fomite; SARS-CoV-2; Systematic review; Transmission; Viral culture.

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Figures

Figure 1
Figure 1
PRISMA flow chart showing the process for the inclusion of studies that performed viral culture to assess transmission of SARS-CoV-2 through fomites.
Figure 2
Figure 2
Risk of bias in studies assessing fomite transmission of SARS-CoV-2.
Figure 3
Figure 3
Relationship between cycle threshold and viral culture results in fomites.
Figure 4
Figure 4
Forest plot showing the relationship between CT and viral culture results.
See this image and copyright information in PMC

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