90-Second Read: Vaccines and therapeutics for Andes Hantavirus

The recent outbreak of Andes Hantavirus (ANDV) on a cruise ship has raised concerns. So far, human-to-human transmission has only been reported for a single species, for ANDV, a highly pathogenic HCPS-causing Hantavirus with a case fatality rate ranging between 30-50% 2. Neither effective therapeutics nor licensed vaccines are available against ANDV and most of the other members of the Hantavirus family. Infections of humans are reported frequently, with more than 100,000 estimated cases annually 1 and are typically caused by inhalation of contaminated excreta of rodents or by direct contact with rodents or their excreta or body fluids.

Recently, ANDV was the causative agent of an outbreak on the cruise ship MV Hondius with 13 confirmed cases and three deaths so far and likely human-to-human transmission on board. Hantavirus disease has already been described during the Korean War in the 1950s, and research on developing effective vaccines and antivirals is ongoing since then. 3) Attempts to create infectious virus clones via reverse genetics failed so far, limiting research on Hantaviruses, and the development of live attenuated vaccines. Thus, Hantaviruses grow only to low titers and often do not cause cytopathic effects (CPE), which limits efficient production of inactivated virus vaccines.

While it is unlikely that Hantaviruses will cause the next pandemic, increasing numbers of Hantavirus infections are observed globally over the last years and the tendency of ANDV to transmit from human to-human is concerning. Each Hantavirus typically infects one specific host species, in which they cause persistent, mostly apathogenic infections with viral shedding in excreta and body fluids. Hantaviruses establish infections in humans mostly via the respiratory tract; however, most candidate vaccines are administered via the intramuscular route and not via the mucosal route (e.g., intranasal application) to induce a strong mucosal immune response. Two recombinant human monoclonal antibodies that protect against lethal Andes Hantavirus infection in vivo.

Adenovirus vectors expressing Hantavirus proteins protect hamsters against lethal challenge with andes virus. Effect of Vandetanib on Andes virus survival in the hamster model of Hantavirus pulmonary syndrome. However, in different clinical trials (reviewed in 7 ), the immunity induced by the vaccine was considerably low, waned within months, and was not cross-reactive to other Hantaviruses.