A hot topic since their introduction in 1798: vaccines. Vaccines work by training your immune system to detect and combat pathogens like viruses and bacteria. For this to work molecules of the pathogen have to be introduced to the body and trigger an immune response.
Those molecules are called antigens which are present in all viruses and bacteria. Those antigens when injected activate the immune system and allow it to safely detect them as hostile, produce antibodies, and remember them for the future. This means when that same virus or bacteria appears the immune system can recognize it and immediately respond with an offensive to stop spreading and sickness in the body.
There are multiple types of vaccines and so these are the main types the public will encounter:
- Live Attenuated Vaccines. Live vaccines utilize a weaker asymptomatic form of the bacteria or virus in their injection. Due to its weakened state, the pathogen does not spread, and cause sickness yet still allows the immune system to develop recognition and combative strategies for future infection.
- Examples include Measles, Mumps, Rubella (MMR combined), Varicella (Chickenpox), Influenza (nasal spray), and Rotavirus.
- Inactivated Vaccines. These vaccines utilize the dead cells of a specific virus after they have been killed with heat or chemicals which are then injected into the body. Despite the pathogen being dead, the immune system is still able to learn from the antigens.
- Examples include Polio (IPV), Hepatitis A, and Rabies.
- Subunit/conjugate Vaccines. In some cases, scientists isolate a specific protein or carbohydrate from a disease then inject it into the body. This trains the immune system to react to the pathogen without causing sickness in the individual.
- Examples include Hepatitis B, Influenza (Flu), Haemophilus Influenzae Type B (Hib), Pertussis, Pneumococcal, Human Papillomavirus (HPV), Meningococcal
- Toxoid Vaccines. For bacterial diseases that damage the body through the secretion of harmful chemicals or toxins, scientists can “deactivate” some of the toxins. This is done using a combination of formaldehyde and water then those dead toxins are injected into the body. The immune system can now fight off the live toxins encountered in the future.
- Examples include Diphtheria and Tetanus.
- Conjugate Vaccines. Bacteria can possess an outer coating of sugar molecules which allow it to camouflage their antigens and trick a young immune system. To beat this, scientists can link an antigen from a recognizable pathogen to the coating. This allows the body’s immune system to detect the coating as hostile immediately and attack it and its antigens.
- A main example is Haemophilus Influenzae Type B (Hib)