Rapid and reliable inactivation protocols for the diagnostics of emerging viruses: The example of SARS‐CoV‐2 and monkeypox virus

Abstract

The emergence and sustained transmission of novel pathogens are exerting an increasing demand on the diagnostics sector worldwide, as seen with the ongoing severe acute respiratory coronavirus 2 (SARS‐CoV‐2) pandemic and the more recent public health concern of monkeypox virus (MPXV) since May 2022. Appropriate and reliable viral inactivation measures are needed to ensure the safety of personnel handling these infectious samples. In the present study, seven commercialized diagnosis buffers, heat (56°C and 60°C), and sodium dodecyl sulfate detergent (2.0%, 1.0%, and 0.5% final concentrations) were tested against infectious SARS‐CoV‐2 and MPXV culture isolates on Vero cell culture. Cytopathic effects were observed up to 7 days postinoculation and viral load evolution was measured by semiquantitative polymerase chain reaction. The World Health Organization recommends an infectious titer reduction of at least 4 log 10 . As such, the data show efficacious SARS‐CoV‐2 inactivation by all investigated methods, with >6.0 log 10 reduction. MPXV inactivation was also validated with all investigated methods with 6.9 log 10 reductions, although some commercial buffers required a longer incubation period to yield complete inactivation. These results are valuable for facilities, notably those without biosafety level‐3 capabilities, that need to implement rapid and reliable protocols common against both SARS‐CoV‐2 and MPXV.

Review of virological methods for laboratory diagnosis and characterization of monkeypox virus (MPXV): lessons learned from the 2022 Mpox outbreak

“…The results showed that the MPXV DNA was stable over 5 days of storage with no significant drop in Ct values observed, even when the DNA aliquot was exposed to temperatures above 30 °C for several hours on day 3. This stability is consistent with the results of other studies (97,99). In addition, the DNA stability after MPXV inactivation using an autoclave (121 °C, 30 min) was investigated.…”

“…In addition, evaluations of commonly used reagents in clinical laboratories such as Trizol and commercially available lysis buffer AVL with ethanol were performed, showing inactivation of MPXV after a 10-minute incubation at room temperature (98). A study testing seven commercial diagnostic buffers confirmed inactivation of MPXV at different incubation times, and heat (56 °C and 60 °C) and sodium dodecyl sulfate detergent were also found to be effective, highlighting the importance of matching the protocol to downstream biological processes (99).…”

Evaluation of Stability, Inactivation, and Disinfection Effectiveness of Mpox Virus

“…This was consistent with the conditions recommended in many guidelines. This effective inactivation condition requires higher requirements, compared to reports that MPXV can effectively inactivate at 56 °C for 10 min (titer reduction > 6.9 lg TCID 50 /mL) [ 31 ]. Some studies have also shown that MPXV can be inactivated at 70 °C for less than 5 min, which is less than the required 10 min in this study [ 32 ].…”

Current status of pathogen handling in European laboratories: focus on viral inactivation process

“…Consequently, there are many studies or guidelines describing specific protocols for chemical or physical inactivation of viruses. In practice, this regulatory framework does not harmonize practices or guarantee their effectiveness as demonstrated by recent viral outbreaks and the need for systematically published new protocols to protect laboratory workers ( Quéromès et al, 2023 ).…”