Vaccines are only given to children after a long and careful review by scientists, doctors, and healthcare professionals. Vaccines will involve some discomfort and may cause pain, redness, or tenderness at the site of injection, but this is minimal compared to the pain, discomfort, and trauma of the diseases these vaccines prevent. some vaccine-preventable diseases can result in prolonged disabilities and can take a financial toll because of lost time at work, medical bills, or long-term disability care