Thread by @ZdenekVrozina

COVID turns common EBV reactivation into a clinically significant event.

A new Czech study (Cell Reports, 2025):
SARS-CoV-2 can trigger Epstein-Barr virus (EBV) reactivation - and in some people, that leads to long-term lung damage in long COVID.🧵

The study analyzed 687 people with long COVID (4–16 weeks after infection).
Tests included:
lung function & chest X-ray
EBV serology (VCA IgM, IgA, EA-D IgG)
EBV DNA in blood
IL1/IL10 genetics
cytokines & immune profiling

Signs of recent EBV reactivation were found in 23% of patients.
Key marker: anti-VCA IgA
This antibody:
indicates a strong, recent EBV reactivation
correlates with lung damage and higher EBV viral load in blood

Reactivation was more common in people with certain genetic variants:
IL1A rs1800587 GG
IL1B rs1143634 GG
IL1RN rs315952 TT / rs579543 A

These variants increase IL-1Ra, dampen inflammation
Easier for EBV to reactivate and persist

Patients with EBV reactivation were more likely to have:
2× higher chance of abnormal chest X-rays
reduced gas exchange (DLCO, KCO)
higher latent EBV levels in blood

Often without reporting stronger symptoms!

But EBV reactivation is common, right?
Yes - even in pre-pandemic controls, it occurred in - 27%.
At first glance: COVID might not be involved.
But hold on:

The difference was not how many reactivated EBV - but how strongly and with what consequences:
Long COVID patients had much higher levels of anti-VCA IgA
This correlated with lung injury and EBV DNA in blood
COVID-19 thus modulates reactivation:
From a harmless event - to a biologically active one

Takeaway:
SARS-CoV-2 can facilitate EBV reactivation in genetically predisposed individuals
This reactivation may be “silent” - but causes measurable damage
Long COVID is not just about SARS-CoV-2 - it’s about what the virus sets off inside the host

The study was led by a team from University Hospital Olomouc & Palacký University in the Czech Republic.
It shows how viral interactions + host genetics = persistent inflammation & damage @marian_hajduch @szupraha @ZdravkoOnline cell.com/cell-reports/f…