The world is depending on the success of vaccine programs to end the ongoing COVID-19 pandemic. To curb the spread of the virus, it is essential for a population to reach herd immunity, where a significant proportion has developed immunity to infection. There are currently 11 vaccines authorized/approved for use in multiple countries worldwide. According to clinical trial data, these vaccines have demonstrated relatively high efficacy in preventing COVID-19 infection. However, this does not mean that the vaccines will be as effective in the real world. Vaccine response can vary at an individual level and can be influenced by a multitude of biological factors, including the function of the microbiome.
The microbiome plays a significant role in immunity, and may be an underlying factor explaining why elderly people and those with certain comorbidities are at higher risk of infection. The underlying impact of microbiome dysbiosis on immunity may not only increase instances of severe disease in high risk groups but may also affect their response to the COVID-19 vaccines
