Correlations of Long COVID Symptoms and Inflammatory Markers of Complete Blood Count (CBC): A Cross-sectional Study

Long-COVID refers to lasting unspecific symptoms like fatigue, decreased concentration and sleep issues after infection which persist for at least three months and cannot be attributed to other causes. Previous studies surveyed the association between inflammatory markers like C - reactive protein (CRP) at hospital admission and long-COVID symptoms in the preceding months. Post-COVID syndrome can affect one-third of patients. Thus early diagnosis can assist in reducing burdens on public health. We attempted to see any correlations between complete blood count (CBC) markers (like red blood cell (RBC), white blood cell (WBC), Neutrophil to lymphocyte ratio (NLR), etc.) at hospital admission and long COVID symptoms at a 6-month follow-up.

167 patients (44.9% females, mean age 49 years old) answered semi-structural interviews through telemedicine which focused on the three prominent symptoms: fatigue, loss of concentration and decreased libido. Results: Two third of patients have symptoms of long COVID and others do not have. NLR in the symptomatic group was statically higher. Patients who underwent decreased libido at a 6-month follow-up had significantly more severe lymphopenia (p = 0.028) and higher NLR values (p-value = 0.007). Poor mental concentration is associated with high WBC in numbers and polymorphonuclear (PMN) count. Other symptoms do not correlate with blood markers.

Utilizing available data like CBC can help predict the upcoming symptoms of previously hospitalized patients and further measures like rehabilitation. Additional investigations should be done on the effect of COVID vaccination on converting long COVID. Different variants of the virus may have different results.