Vaccines are very effective in preventing serious outcomes and complications following infection with a virus. However, vaccines do not prevent infection and transmission. The solution to halting any pandemic is to prevent community transmission and new outbreaks. To date there are no therapeutic interventions that prevent transmission of any viral infection.
Interferons are broad-spectrum antivirals that inhibit any and all viral infections and activate the host immune response to assist with viral clearance. Most pertinent for pandemic preparedness, the scientific literature is replete with evidence that interferons protect uninfected cells, tissues, animals and humans from infection, i.e., provide prophylactic protection. We have conducted a ring prophylaxis trial where we found evidence that interferon treatment of uninfected individuals in a household exposed to a confirmed SARS-CoV-2 infected individual protected them from infection, or, among those who became infected, helped reduce viral load (i.e., less severe disease). This research program continues with the development of a nasal formulation of an interferon to be examined in Phase 1, 2 and 3 clinical trials, for protection from serious respiratory virus infections including flu, RSV and SARS-CoV-2.