Both HHV-6 and specific microRNAs may correlate with neurological symptoms in COVID-19.
HHV-6 was the most common herpesvirus found when tested in nasal swabs, but EBV was the most common in plasma.
Pityriasis rosea was reported more frequently after vaccination than during or after acute infection.
Systematic review and meta-analysis found strong evidence for EBV in the seriously ill; only 6 of 36 studies included HHV-6 testing.
Other studies have suggested that reactivation of these viruses could theoretically contribute to a hyperinflammatory state or autoimmune disorders in acute COVID-19, but this study does not provide evidence of that.
40% of the patients with HHV-6 DNA had CNS symptoms, compared to 14.3% of the HHV-6 negative patients.
EBV, CMV, and HHV-6 reactivation were found in a small cohort of severe COVID-19 patients
So far only one case report has documented HHV-6B reactivation in COVID-19, but the rise in Kawasaki-like symptoms and pityriasis rosea has at least one dermatology group suspicious of HHV-6/7 reactivation.