The epidemic is not expected to be anything out of the ordinary. If you strongly want a flu shot, I'd say get it. I know several people who swear by their annual flu shots, and if you had a very bad case last year, the vaccine may give you peace of mind. In an ordinary year I recommend flu shots only to people who have chronic respiratory illness or who are elderly, debilitated or have compromised respiration for any reason. You also may want to consider other ways to boost your immune system against the flu.
Astragalus is a Chinese tonic herb, known as huang qi.
Traditional Chinese doctors recommend it to increase resistance to disease and to improve immune function. It may increase the body's production of interferon, which triggers cellular defenses against viruses. You can buy it in tinctures and capsules in health food stores, or use the bundles of thin slices from Chinese herb shops. Use the slices in soups and remove them before serving. For the prepared products, follow dosages specified on the labels.