Optimism as a key factor in coping with the common cold.

Objective: The optimism trait is considered one of the most important psychological factors in protecting and promoting health. This study aims to investigate whether trait optimism may help to cope better with the common cold by reducing the subjective perception of cold symptoms and affecting the immune response. Methods: To do so, 212 volunteers from the Pittsburg Cold Study 3 within the Common Cold Project were exposed to Rhinovirus (RV39). On the 5 days following the inoculation, a daily symptoms scale, nasal wash, and blood samples were collected to assess Jackson Symptoms (nasal congestion, sneezing, runny nose, sore throat, cough, headache, chills, and malaise) and control the Immune System response to infection (concentrations of interleukin (IL)-1β, IL-6, IL-8, IL-10, tumour necrosis factor (TNF)-α, and interferon (IFN)-α). Results: Results showed that approximately 30% of the inoculated participants were finally diagnosed with a common cold, showing higher Jackson Symptom severity and Immune System Response (IL-1β, IL-6, IL-8, IL-10, TNFα and IFNα). Importantly, moderation regression analyses showed that higher optimism scores were related to lower Jackson Symptom severity and TNFα response to infection in cold-diagnosed participants. Conclusions: Our results provide important evidence for the protective role of optimism, a trait factor that promotes a better perception of wellbeing and less need for immune system resources to successfully cope with the common cold.