STRESS VS. THE FLU VACCINE

BY OLIVIA WALLON – Flu season is like a groundhog day for America. Campuses and offices are littered with flyers and posters to get vaccinated. News articles claim that this flu season is the worst yet, and the public is repeatedly told the same tips to stay healthy: keep hands clean, get vaccinated, and avoid others with the flu. This “trifecta” to avoid the flu has been ingrained in the public’s mind for years, resulting in a feeling of invincibility to those who follow each step meticulously. But there is a flaw in this system. Recent studies have clued that an individual’s susceptibility to the flu is not based solely on physical factors, but stress levels too.

Stress is the body’s response to demand, both positive and negative. The body’s threat reaction initiates a “flight or fight” response that results in focus, energy, and alertness. The initial stress response originates in the brain. The amygdala sends a threat-like message to the hypothalamus, which directs the sympathetic nervous system to engage and protect. The triggering of the sympathetic system affects the pituitary gland, the heart, adrenal glands, and the digestive system. Heart rate increases, blood vessels constrict and dilate, digestive processes slow down, and cortisol is secreted. Some stress is beneficial to trigger motivation, but when persistent negative stress is present, there seems to be a drop in physical health.  

A study conducted by Gregory Miller and colleagues analyzed the effects of stress levels on antibody production in students. Each student recorded their stress levels over a 13 day period. During this time, the students had their baseline antibody levels recorded and were administered a vaccine. The individuals’ antibody count was also measured one month after vaccination and four months after vaccination. The researchers then analyzed the self reported stress for each individual and calculated average daily stress and a cumulative stress index. Researchers then created three groups; low-stress individuals, medium-stress individuals, and high-stressed individuals. Initially, all 3 groups reported similar baseline antibody levels. But at both the one month and the four month check in, the high-stress group had considerably less antibodies compared to the other two groups. They also saw consistency in low antibody production with those who experienced high level stress between eight and ten days after vaccination, around a twelve to seventeen percent decrease.

In a meta-analysis of 13 studies, Pedersen and colleagues explored the hypothesis that stress contributes to a high risk of contracting influenza and a lower antibody count. The studies consisted of comparing increased antibody levels of vaccinated caregivers verses vaccinated non-caregivers, and an individual’s self reported stressors and antibody production after vaccination. The 13 studies all had consistent results involving higher psychological stress and a lower than normal level of antibodies after being exposed to the flu vaccine. The findings also hinted that stress’ effects on antibody production did not change based on age, sex, or race, but solely on an individual’s stress levels.

These studies, along with a multitude of others, support the idea that stress is debilitating to the immune system because of the body prioritizing “fight or flight” over things like antibody production. Antibodies are crucial for the immune system. Their jobs are to latch onto and terminate antigens, which are potentially dangerous foreign pathogens. The immune system also uses antibodies as a form of memory, meaning that if the body successfully fights off a foreign pathogen with specific antibodies, these antibodies will be stored, creating a life long immunity to a specific antigen. This “memory” is what makes vaccines effective. In specific, the flu vaccine works by introducing small amounts of the flu virus into the body, stimulating antibody production. This predisposition to the flu virus allows a person to have less of a chance to contract the flu, especially during peak flu season. These studies hint the effects of stress on vaccines by showing that chronically stressed individuals had insufficient antibody production, resulting in an almost ineffective flu vaccine.

As this flu season approaches, it is important to focus on not only physical health, but mental health too. Integrating practices like exercise, a balanced diet, and meditation are often suggested to help ease stress. Although finding time to relax may not be as easy as a prick in the arm or using hand sanitizer, it is vital to be mindful of stress levels, because no one wants the flu.