A new study suggests that a smile can help reduce pain during vaccination. Researchers proved that people who smiled or grimaced while getting a vaccination experienced a lower level of pain when compared to people who didn’t smile while getting a shot. Whenever people face pain they tend to close their eyes tightly and bare their teeth which are often referred to as grimace response.


This study makes a new protocol in helping phobic patients. The researchers asked the patients to smile just prior to the vaccination and asked them to report their level of pain. They specifically wanted to understand whether manipulating the patient’s facial reaction during vaccination will help to reduce their pain and stress.


Sarah Pressman, Ph.D., a professor of psychological science at the University of California, Irvine and the study’s lead author tells that “In our study, faking a big, Duchenne smile before and during a sham vaccination not only made the needle hurt about half as much, but it also made people anticipate that the needle would hurt less before they got it.” and “In addition, it reduced the physiological stress response associated with needle anxiety.”


To investigate the link between facial expression and pain sensation, the scientists decided to recruit 231 members. They all were shot with saline with the same injection which is used for the flu vaccine. The scientists then split the members into four groups like a Duchenne smile, a non- Duchenne smile, a neutral expression, and a grimace in order to recognize their reaction after receiving the shot with chopsticks in their mouth.


Before receiving the vaccination they stress levels were also recorded and after receiving the shot the medical examiner asked them to report their pain levels and stress levels. And also they were connected with an electrocardiogram to measure the changes before, after, and during the vaccination.


In addition to this, Electrodermal Activity (EDA), the measure of psychological and physiological changes in the participant’s skin were also measured. When the researchers measured the heart rate data, it seems to be that the Duchenne smile group has a lesser heart rate than the neutral groups and there were no significant changes in the grimace and the non-Duchenne group.


The research shows that people who smile or grimace while receiving the shot will experience 40% of less needle pain when compared to the other groups. Together the researchers hope that it can help and encourage people to get vaccinated even if they are phobic to injections and pain.