Seroepidemiology of Human Cytomegalovirus and Human Herpesvirus 6 in a Cohort of Healthy Blood Donors from Abbottabad, Pakistan

Background. Human Cytomegalovirus (CMV) and Human Herpesvirus 6 (HHV-6) represent significant public health concerns due to their widespread prevalence and potential clinical sequelae. This study aimed to elucidate the sero-epidemiological profile of CMV and HHV-6 among a cohort of ostensibly healthy blood donors in Abbottabad, Pakistan. Methods. A cross-sectional study was conducted from December 2021 to June 2022 at the Regional Blood Centre in Abbottabad. Initially, 1850 healthy male blood donors were recruited according to WHO criteria, with 1750 meeting eligibility after screening for high-risk behaviors and clinical symptoms. Plasma samples were assayed for anti-CMV IgG, CMV IgM, and HHV-6 IgM using ELISA kits (sensitivity: 99%, specificity: 95%), with optical density measured at 450/620 nm. Donors were stratified into four age groups (<18, 21–30, 31–40, and 41–50 years) and statistical analyses were performed using descriptive statistics and Pearson’s Chi-square test (p<0.05) in SPSS (version 25). Of the 1850 initially recruited donors, 1750 met the inclusion criteria (mean age: 28.2 years; range: 19–50 years). Results. Initial screening revealed low prevalence rates for HBsAg (0.69%), anti-HCV (2.4%), and syphilis (1.14%), with all donors testing negative for malarial parasites and HIV. Blood group distribution was predominantly O (36%) and B (36%), with 96% of donors being Rh-positive. Overall, serological assessment demonstrated a CMV IgG seroprevalence of 90.2%, CMV IgM positivity in 5.7%, and HHV-6 IgM positivity in 8% of donors. Age-stratified analysis indicated: donors aged <18 years exhibited 80% CMV IgG positivity (with no CMV IgM or HHV-6 IgM), those aged 21–30 years 89% CMV IgG, 5.45% CMV IgM, and 9.1% HHV-6 IgM positivity; donors aged 31–40 years showed 94.2% CMV IgG, 7.69% CMV IgM, and 7.6% HHV-6 IgM positivity; while donors aged 41–50 years demonstrated universal CMV IgG positivity without detectable CMV IgM or HHV-6 IgM. Conclusion. The elevated CMV IgG seroprevalence among Abbottabad blood donors indicates widespread viral exposure, while the lower rates of CMV IgM and HHV-6 IgM suggest infrequent recent or reactivated infections. These findings underscore the need for continued sero-epidemiological surveillance to inform and optimize regional blood safety protocols.