Disease & body defence
Communicable and non-communicable diseases, vaccines and antibiotics, and how medicines are developed.
Communicable (infectious) diseases are caused by pathogens: bacteria, viruses, protists and fungi. Sexually transmitted infections spread through sexual contact; HIV attacks the immune system and can lead to AIDS.
Treatment and prevention: antibiotics kill bacteria (not viruses); vaccines contain dead or inactive pathogens that trigger antibody production and memory cells, giving future immunity; spread is reduced by hygiene and isolation.
New medicines and vaccines go through pre-clinical testing (in the lab, on cells and animals) then clinical testing (on healthy volunteers and patients) to check they are safe and effective before use.
Non-communicable diseases arise from the interaction of many factors, including cardiovascular disease, many cancers, some lung and liver diseases, and diet-influenced conditions like type 2 diabetes. Cardiovascular disease is managed with medication (statins, anti-coagulants, anti-hypertensives), surgery (stents, bypass) and lifestyle changes (less smoking, more exercise, a balanced diet).
- Saying antibiotics treat viruses (they only work on bacteria).
- Thinking a vaccine contains the active disease; it uses dead or inactive pathogens.