Antiviral treatment with valacyclovir reduces virus shedding in saliva of Antarctic expeditioners

• Published in: Frontiers in Virology
• Main Authors: Satish K. Mehta, Douglass M. Diak, Bridgette V. Rooney, Stephanie S. Krieger, Mayra Nelman-Gonzalez, James P. Locke, Maria A. Nagel, Millennia Young, Brian E. Crucian
• Format: Article in Journal/Newspaper
• Language: English
• Published: Frontiers Media S.A. 2023
• Subjects: antiviral; herpes viruses; Antarctic; countermeasure; valacyclovir HCl; Microbiology; QR1-502; South Pole; Antarc*; South pole
• Online Access: https://doi.org/10.3389/fviro.2023.1157659; https://doaj.org/article/45d160da91e14ec3ba429264225547e4

IntroductionReactivation of herpes viruses, such as Epstein–Barr virus (EBV), herpes simplex virus 1 (HSV1), and varicella zoster virus (VZV), increases in astronauts during spaceflight, compared with their preflight and postflight levels. Reactivations can increase the risk of associated clinical conditions, such as herpes zoster, chronic neuropathic pain, vision loss, stroke, cognitive impairment, and cold sores. Furthermore, continued viral shedding for longer periods after space travel may increase the risk of viral transmission to uninfected crew contacts, including, but not limited to, the immunocompromised and newborn infants. Thus, it is essential to develop spaceflight countermeasures to prevent herpes viral reactivations to ensure the health of crewmembers and their contacts. One such countermeasure is the prophylactic administration of an antiviral drug (valacyclovir) against the alpha herpesviruses (VZV and HSV1). To determine the effectiveness of this countermeasure, we studied the shedding of EBV, VZV, and HSV1 in Antarctic expeditioners, who have similar salivary viral shedding patterns during winter-over to astronauts during long spaceflights.MethodsThe efficacy of this antiviral drug as a countermeasure was determined using three major parameters in the saliva of expeditioners during winter-over with and without administration of this drug: (i) viral load and frequency, (ii) physiological stress biomarkers [i.e., levels of cortisol, dehydroepiandrosterone (DHEA), and amylase), and (iii) immune markers (i.e., inflammatory cytokines)]. Thirty-two volunteers from two Antarctic stations (McMurdo and South Pole) participated in this study. Participants were randomly assigned to either the treatment group (valacyclovir HCl: 1 g/day) or placebo group (oyster calcium: 500mg/day). ResultsViral shedding of EBV reduced significantly (> 24-fold) in the treatment group compared with the placebo group. HSV1 was also reduced by more than fivefold, but this was not statistically significant. No VZV shedding ...