Definition of HCV Reactivation [Letter]

Dear editor

We have read with great interest the paper by Lensen et al.¹ They reported a case of HCV reactivation developing following a COVİD 19 vaccination. However, we have some concerns regarding the case.

Firstly, the patient had decompensated cirrhosis in 2015. However, its etiology was not clearly mentioned. It should have been specified in the text.

Secondly, she was diagnosed with hepatitis C virus infection in 2007. The tests including HCV-RNA and genotype were not available and it was not known whether she achieved a sustained viral response. Also, she had slightly increased liver enzymes since 2011. We think it is probably to be caused by HCV.

Thirdly, more importantly, the term “reactivation of HCV infection” is used for patients resolved from the infection, namely a positive HCV antibody test and a negative for HCV RNA.³ However, it is not known in this case. Also, reactivation of HCV infection is defined as a rise in the HCV RNA level of at least 1 log₁₀ IU/mL from baseline, as HCV RNA levels in chronically infected patients may fluctuate by about 0.5 log₁₀ IU/mL.^2,3 It is crystal clear that the patient does not meet the criteria for a case definition because follow-up HCV RNA levels were not present. In the patient, it could be only stated that she had hepatitis with the elevation of liver enzymes. Due to findings including fever, elevated CRP and somnolence, and abdominal pain, the systemic infection including sepsis, cholangitis and spontaneous bacterial peritonitis are primarily considered in this case. In the light of these data, it is impossible to state that the patient had reactivation of HCV infection developing following a COVID-19 vaccination.