However, the study, which was not peer-reviewed, has since been retracted Health24 spoke to a professor in nutrition science who said that further research is needed, and warned against taking high doses as a preventative The Covid-19 pandemic has brought on a heightened fear of infection for us and our loved ones, leading us to do all we can to minimise exposure and improve our overall immunity. But while maintaining a healthy vitamin D level can play a role in having a healthy immune system, it’s unclear whether it may help us to fight Covid-19 more effectively and quickly, as well as reduce the chances of hospitalisation – as some studies have suggested.