Vaccination

• Vaccines work by exposing our bodies or immune systems to a certain pathogen, developing immunity to it, and preventing us from catching the disease.
• The problem with vaccines is that we still have to catch the disease the first time, which can range from being unpleasant to lethal.
• Vaccines work by containing the pathogens that we want to be immune to, but they've been weakened or inactivated so they can't cause us any disease.
• Our bodies still treat these weakened pathogens as if they're the proper pathogens, and so they respond by producing antibodies and developing immunity.
• Vaccines are available for many diseases, including both bacteria and viruses, and by the time we start primary school, we've already been vaccinated against more than a dozen diseases that could otherwise kill us.
• Vaccines have helped us control diseases like polio, smallpox, measles, and whooping cough, and they prevent big outbreaks of disease, known as epidemics.
• Vaccines work because of a concept called herd immunity, where enough people in a population are immune to a pathogen, preventing the pathogen from spreading and causing disease.
• Vaccines don't always work, sometimes they just don't grant us full immunity, but with important vaccines, we generally check after the injection to see if it's been effective.
• A common problem with vaccines is that some people have bad reactions to the vaccine, such as swelling around the injection site, fevers, or even seizures, but these reactions are rare and the severe reactions are super rare.