Long COVID is characterized by symptoms that persist for three months or longer after the initial COVID-19 infection, impacting an estimated 5 to 10 percent of cases, with many patients not feeling normal for 12 to 18 months.

A recent study published in the journal Infection analyzed blood samples from individuals with long COVID symptoms and identified 65 distinct SARS-CoV-2 protein fragments in extracellular vesicles (EVs), suggesting the virus may linger in the body long after infection.

Extracellular vesicles are nanosized particles that transport proteins and other molecules between cells, and they have been known to carry viral materials in previous infections.

While the study detected these peptides, researchers did not find evidence of active viral replication in the patients tested, indicating that the peptides could be remnants from past infections.

The exact nature of the identified peptides remains unclear, as they might represent leftover material from viral protein formation rather than active viral replication.

The stability and timing of the molecular signals in blood samples raised questions about whether exercise triggers the release of viral material or if the peptides are simply remnants from earlier infections.

An ongoing clinical trial is exploring the relationship between EVs, immune function changes related to exercise, and post-exertional malaise, a common symptom in long COVID patients.

William Stringer from the Lundquist Institute for Biomedical Innovation highlighted the lack of confirmatory tests for long COVID diagnoses until now.

If validated, the detection of EV-based peptides could lead to a valuable diagnostic tool and inform treatment strategies for long COVID.

In a related context, a recent study estimated that COVID-19 vaccinations saved 2.5 million lives between 2020 and 2024, underscoring the importance of staying updated with vaccinations as new variants emerge.