Immunization is a global health and development success story, saving millions of lives every year. Vaccines reduce risks of getting a disease by working with your body’s natural defences to build protection. When you get a vaccine, your immune system responds.We now have vaccines to prevent more than 20 life-threatening diseases, helping people of all ages live longer, healthier lives. Immunization currently prevents 3.5-5 million deaths every year from diseases like diphtheria, tetanus, pertussis, influenza and measles. Immunization is a key component of primary health care and an indisputable human right. It’s also one of the best health investments money can buy.