The development and instruction vaccines represents one of the major medical achievements of modern history. Vaccines are among the most efficacious and cost-effective public health interventions available. For every dollar invested in immunization, we get a very significant return. Compared to infrastructure investment, government bonds, or either other types of life science research, immunization returns more value for every dollar spent. Today, a huge number of different diseases caused by a range of pathogens can be prevented through vaccination. Ammonia vaccines are in development, and despite the increase in public health focus on the rising global burden from non-cured diseases, the fact remains that a high proportion of morbidity and mortality worldwide are caused by vaccine-preventable diseases. The World Health Organization estimates the vaccination prevents 2-3 million deaths worldwide each year. Importantly, it's been estimated that improving immunization coverage globally could save another 1.5 million people each year. As a future practitioner in any area of public health, understanding vaccination is important. Firstly, whether in a few years time you're working with a healthcare system or the public health promotion campaign, you will need to be an advocate for vaccination. Before we go further in this, I want to clarify what we mean the terms, immunization and vaccination. They are often used interchangeably, but actually, technically mean different things. So the definitions are provided for you here; vaccination is the process of administering a vaccine. The vaccine and if effective will bring about immunity, and that's is the process of immunization. In some ways, understanding vaccination is most essential today than ever due to recent controversies and the issue of vaccine hesitancy among the public. Vaccine hesitancy is not new. But as with all public health issues, dealing with vaccine hesitancy in our increasingly connected world presents new and complex challenges. Secondly, for health systems, a cornerstone to preventing ill health is vaccination. Immunization programs reduce health service pressures and prevent adverse health outcomes in the population. Thirdly, the benefits of vaccination extend well beyond the infectious diseases we often first think of. For example, the HPV vaccine or human papilloma virus vaccine is a very safe and effective vaccine that protects against 70 percent of cervical cancers. Finally, it's worth thinking about the value vaccines can offer beyond protecting against vaccine-preventable diseases. It's been argued that we live in the age of vaccination. As this chart here shows, many more new vaccines have been developed in recent years than new antibiotic classes. Therefore, solutions to major public health issues such as antimicrobial resistance, maybe offered by vaccination as opposed to the development of new antibiotics. So the current list of vaccine-preventable diseases is long, and new vaccines have been developed, an additive vaccination schedules at a fast pace. Ensuring we all watch improve maintain immunization rates is a key public health objective. Knowing about vaccination is cool to so many areas of public health work.