Aspirin is an established, safe, and low-cost medication in long-standing common use in prevention and treatment of cardiovascular diseases, and in the past a pain relief and fever reducing medication. The use of aspirin was very popular during the 1918 Spanish Influenza pandemic, several decades before in-vitro confirmation of its activity against RNA viruses. Studies showed that aspirin, in addition to its well-known anti-inflammatory effects, could modulate the innate and adaptive immune responses helping the human immune system battle some viral infections.