👉 Antiphthisic is a medical term used to describe an individual who does not have any symptoms of influenza (flu) and yet has developed antibodies against it. This condition typically occurs in individuals who have been vaccinated or have had previous exposure to the flu virus, but do not experience the typical flu-like symptoms such as fever, cough, sore throat, body aches, etc. Antiphthisic individuals may also be able to pass on antibodies from their immune system to others who are infected with