A metabolic hormone could negatively impact the effectiveness of Covid-19 vaccines, a new study has warned.
Leptin is a metabolic hormone largely produced in the body by fatty tissue, and researchers from the University of Queensland found that reduced levels of leptin was linked to poor vaccine antibody responses.
Study leader Professor Di Yu identified a link between the body's metabolic and immune systems while investigating responses to the influenza vaccine or hepatitis B vaccine before the Covid outbreak.
"Using multiple advanced techniques in immunology, genetics and biochemistry, our study found leptin directly promoted the development and function of cells which are vital in triggering an antibody response," he explained.
The study found that leptin was associated with "compromised vaccine responses" in both young and older people.
Yu said that the findings could help identify those individuals who were at risk of not having a sufficient antibody response after being vaccinated.
He said that being fit and healthy can help to keep leptin levels steady, and while vaccines affect people differently, we have a much better vaccine efficacy "when we are fit and healthy".
"If we are healthy, we have a good metabolism and a normal level of leptin, but if we have malnutrition or some disease conditions, we may have a low level of leptin, which may limit our vaccine response and immune protection," Yu explained.
However, people with obesity may have leptin resistance due to high levels of fatty tissue, and could also have a poorer vaccine response, but further research is needed.