Eurosurveillance - Volume 28, Issue 9, 02 March 2023

Lateral flow antigen-detection rapid diagnostic tests (Ag-RDTs) for viral infections constitute a fast, cheap and reliable alternative to nucleic acid amplification tests (NAATs). Whereas leftover material from NAATs can be employed for genomic analysis of positive samples, there is a paucity of information on whether viral genetic characterisation can be achieved from archived Ag-RDTs.

To evaluate the possibility of retrieving leftover material of several viruses from a range of Ag-RDTs, for molecular genetic analysis.

Archived Ag-RDTs which had been stored for up to 3 months at room temperature were used to extract viral nucleic acids for subsequent RT-qPCR, Sanger sequencing and Nanopore whole genome sequencing. The effects of brands of Ag-RDT and of various ways to prepare Ag-RDT material were evaluated.

SARS-CoV-2 nucleic acids were successfully extracted and sequenced from nine different brands of Ag-RDTs for SARS-CoV-2, and for five of these, after storage for 3 months at room temperature. The approach also worked for Ag-RDTs for influenza virus (n = 3 brands), as well as for rotavirus and adenovirus 40/41 (n = 1 brand). The buffer of the Ag-RDT had an important influence on viral RNA yield from the test strip and the efficiency of subsequent sequencing.

Our finding that the test strip in Ag-RDTs is suited to preserve viral genomic material, even for several months at room temperature, and therefore can serve as source material for genetic characterisation could help improve global coverage of genomic surveillance for SARS-CoV-2 as well as for other viruses.

Older age is frequently cited as a risk factor for healthcare-associated infections in general, and surgical site infections (SSIs) specifically.

We aimed to investigate the correlation between age and SSI occurrence.

Data on total hip replacement (THR) and total knee replacement (TKR) surgeries and resulting SSIs documented in the German national surveillance network from a 10-year period from 2009 to 2018 were selected for analysis. SSI rates and adjusted odds ratios (AOR) were calculated and a multivariable analysis to determine risk factors for SSI occurrence was conducted.

A total of 418,312 THR procedures resulting in 3,231 SSIs, and 286,074 TKR procedures with 1,288 SSIs were included in the analyses. For THR, SSI rates were higher in older age groups when compared with the reference age group of 61–65 years. A significantly higher risk was observed in the 76–80 years age group (AOR: 1.21, 95% CI: 1.05–1.4). An age of ≤ 50 years was associated with a significantly lower SSI risk (AOR: 0.64, 95% CI: 0.52–0.8). For TKR, a similar correlation was observed, with the exception of the youngest age group (≤ 52 years), which was shown to have an SSI risk equal to that of the knee prosthesis reference age group (78–82 years).

A strong correlation between increasing age and SSI occurrence was observed for both procedure types. The results of our analyses provide a basis to consider future targeted SSI prevention measures for different age groups.