No, "boost" the immune system is a marketing gimmick and a meaningless statement. The immune system is just that; a system. It’s not a single entity but an extremely complex series of interactions on many levels. It's made up of special cells, proteins, tissues, and organs, and is not something you can just ‘boost’.
If you are run down or have not looking after yourself, your immune function can be improved, by healthy diet and lifestyle; but you cannot improve it past its optimal baseline.
There is no need to start taking herbs, supplements or extra antioxidants if you maintain a healthy diet - you can't get healthier than healthy. In any case, its risky - we don't know long term effects, medicinal herbs are basically crude drugs; their quality and potency are subject to variation as they are not regulated or controlled like pharmaceuticals. What it says on the label may not be what you get in the bottle. They are typically handed out by people with little or no medical training have the potential to interact with other medications. They cannot provide immunity to infection.
Avoid crowds and sick people, wash your hands frequently and make sure your vaccinations are up to date.