Hydrate with tons of water throughout the day, and your immune system will thank you. The foods you eat can also help prevent the common cold. Yogurt is a probiotic and has been shown to boost the immune system, and one serving of seaweed packs more vitamin C than an orange. If you suffer from seasonal allergies, contact your HR department if you have questions regarding urgent care providers and Teladoc services. Teladoc is a national network of U.S. board-certified physicians and pediatricians that lets you resolve your routine medical issues, on-demand 24/7, via phone or online video consultations from wherever you happen to be.