Nikhil Prasad Fact checked by:Thailand Medical News Team Sep 20, 2026 35 minutes ago
A little-studied herpesvirus may deserve closer attention in long COVID research after scientists found strikingly high HHV-7 positivity among patients experiencing persistent neurological and neuropsychiatric symptoms following SARS-CoV-2 infection.
HHV-7 positivity reached 76.7% among patients with neurological or neuropsychiatric long COVID in a retrospective study
Research institutions: Independent Researcher, Paris, France; BelgiumR.E.D. Laboratories S.A., Asse, Belgium.
HHV-7 Positivity Reached 76.7%
Researchers retrospectively examined 30 patients, including 18 women and 12 men ages 21 to 55, who developed persistent neurological or neuropsychiatric symptoms and underwent HHV-7 testing within 24 months of COVID-19. Their results were compared with 320 historical diagnostic tests performed before the pandemic between 2012 and 2019.
The difference was substantial. HHV-7 was detected in 23 of 30 long COVID patients, representing 76.7%, compared with 29.1%—93 of 320 tests—in the historical reference cohort. The difference was statistically significant at p<0.000001. All six patients tested during the first 12 months following SARS-CoV-2 infection were HHV-7-positive.
Viral loads among positive patients ranged from 96 to 2,025 copies per million cells, with most exceeding 250 copies. The laboratory classified results above 50 copies per million cells as positive.
Neuropsychiatric Symptoms Were Common
A particularly notable finding involved neuropsychiatric symptoms. Among the 23 HHV-7-positive patients, 21, or 91.3%, reported intense anxiety, panic attacks or persistent internal agitation. Such prominent anxiety or panic symptoms were not consistently reported among HHV-7-negative patients.
In one longitudinal case, HHV-7 was undetectable before illness but increased as symptoms worsened, reaching 329 copies per million cells at peak severity. Following antiviral treatment, viral levels declined and eventually became undetectable, alongside reported improvements in sleep, heart rate, cognition and social functioning. However, the single case cannot demonstrate that treatment caused the improvement.
An Important Clue, Not Proof
HHV-7 establishes lifelong latency, primarily in CD4+ T cells, and previous research has linked the virus with neurological conditions. This
Thailand Medical News report highlights the possibility that HHV-7 reactivation could be relevant to a subset of patients with neurological long COVID.
However, researchers stressed that the findings are exploratory. The study was small and retrospective, patients were self-selected, symptoms were self-reported, and the historical reference population was not matched by age, sex or clinical characteristics.
Conclusion
The unusually high HHV-7 positivity provides a compelling reason for further in
vestigation, but it does not establish that viral reactivation causes long COVID symptoms. Larger prospective studies using matched controls, standardized clinical assessments and repeated viral measurements are needed to determine whether HHV-7 could eventually serve as a biomarker or therapeutic target.
The study findings were published in the peer reviewed journal: Viruses.
https://www.mdpi.com/1999-4915/18/9/1043
Read Also:
https://www.thailandmedical.news/articles/coronavirus
https://www.thailandmedical.news/articles/long-covid 
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