Accurate Multiplex Assay for Viral Causes of Vesicular Diseases

Assay for monkeypox virus, HSV1-2, HHV-6, VZV and enteroviruses.

The explosion of monkeypox cases revealed the absence of good rapid diagnostics to distinguish a vesicular (blistering) skin eruption caused by monkeypox from other viral vesicular diseases.  Investigators in Australia have created a multiplex PCR assay (QIAstat Kit, Qiagen) for viruses that can produce vesicular skin eruptions: monkeypox virus, HSV1-2, HHV-6, VZV and enteroviruses.  The kits were tested on thawed samples of plasma or vesicular fluids of 124 samples in which conventional test results also were known. (It is unclear how many samples were from plasma vs. vesicular fluid). 

The overall concordance between the QIAstat Kit and conventional testing was 96%. Breaking this down, negative agreement was 100% (e.g. none of the kits gave a positive result when conventional testing was negative, indicating high specificity.)  Positive agreement was somewhat different by virus: 100% for monkeypox, HSV-2, VZV and enteroviruses; 89% for HSV-1; and 82% for HHV-6.  The kits were tested against samples containing vaccinia and various respiratory viruses, and no cross-reactivity was demonstrated.

The authors argue that this kit combines ease of use, rapid results, good sensitivity and excellent specificity, and may aid clinicians in diagnosing the cause of diseases with vesicular skin eruptions. 

Read the full article:  Batty 2023