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

Introduction Reactivation of herpes viruses, such as Epstein–Barr virus (EBV), simplex 1 (HSV1), and varicella zoster (VZV), increases in astronauts during spaceflight, compared with their preflight postflight levels. Reactivations can increase the risk associated clinical conditions, zoster, chronic neuropathic pain, vision loss, stroke, cognitive impairment, cold sores. Furthermore, continued viral shedding for longer periods after space travel may transmission to uninfected crew contacts, including, but not limited to, immunocompromised newborn infants. Thus, it is essential develop spaceflight countermeasures prevent reactivations ensure health crewmembers contacts. One countermeasure prophylactic administration an antiviral drug (valacyclovir) against alpha herpesviruses (VZV HSV1). To determine effectiveness this countermeasure, we studied EBV, VZV, HSV1 Antarctic expeditioners, who have similar salivary patterns winter-over long spaceflights. Methods The efficacy a was determined using three major parameters saliva expeditioners without drug: (i) load frequency, (ii) physiological stress biomarkers [i.e., levels cortisol, dehydroepiandrosterone (DHEA), amylase), (iii) immune markers (i.e., inflammatory cytokines)]. Thirty-two volunteers from two stations (McMurdo South Pole) participated study. Participants were randomly assigned either treatment group (valacyclovir HCl: g/day) or placebo (oyster calcium: 500mg/day). Results Viral EBV reduced significantly (> 24-fold) group. also by more than fivefold, statistically significant. No VZV observed any participants. In 50% samples had measurable DNA (EBV, HSV1, both), 19% There no significant change ratio cortisol DHEA alpha-amylase, indicating that between groups. difference detected cytokines, except IL-10, which found lower Discussion These data indicate valacyclovir safe successful intervention reduce individuals subjected extreme environments stressors.