Vaccination, immunisation and medicines

In a nutshell

Vaccines and certain drugs, such as antibiotics, can be used to prevent the spread of infection. Other drugs, such as painkillers, can relieve symptoms of a disease.

Vaccination and immunisation

Vaccination and immunisation do not mean the same thing. Vaccination involves administering dead or inactive pathogens into a person to prevent disease. The pathogens will carry antigens which cause the lymphocytes to produce antibodies and attack them, even though the pathogen is harmless to you as it is dead or inactive.

The antigens will trigger memory lymphocytes to be made. This means if the individual is infected with the live pathogen, the lymphocytes can quickly produce lots of antibodies to kill that pathogen. Immunisation is the process of being vaccinated and the immunity you develop as a result of the vaccination.

Example

The MMR vaccine carries weakened versions of the measles, mumps and rubella pathogens in one vaccine.

Pros and cons of vaccination

Pros	Cons
Vaccination can control lots of communicable diseases. Example Polio, measles, mumps and rubella.	Vaccines aren't always $100\%$ effective.
Herd immunity can be achieved. This is when a large percentage of the population is vaccinated so big outbreaks of a disease, known as epidemics, can be prevented. This is because people who are not vaccinated are unlikely to catch the disease as there are fewer people to pass it on.	Some people may react badly to the vaccine. This is very rare. Example Swelling or something more serious like seizures.
Immunity is produced without the individual getting ill.
Immunity will usually last a very long time, sometimes even for life.

Medicines

Painkillers

Painkillers are drugs that relieve pain. They don't prevent disease or kill pathogens, but they reduce the symptoms that the disease causes.

Examples

Paracetamol and aspirin can be used to treat headaches.

Antibiotics

Antibiotics are chemicals that kill bacteria without killing human body cells. Antibiotics are often produced naturally by fungi and other microbes.

Example

Penicillin is made from a type of mould.

Antibiotics do not kill viruses and some bacteria are naturally resistant to some antibiotics. Antibiotics can also become ineffective through misuse. For instance, doctors may overprescribe antibiotics or patients may not complete their prescribed course.

Antivirals

Antivirals are used to treat viral infections but do not kill the virus, they just stop them from reproducing. Antivirals are difficult to produce as viruses use the host cell to replicate so the antiviral must target the virus without killing the host cell.

Antiseptics

Antiseptics are chemicals that are used outside of the body to clean wounds or surfaces as they can destroy microbes or stop them from growing. They are not used to treat infections but to prevent them. Many household cleaning products are antiseptics and they are often used in hospitals to prevent the spread of infection.