What is in the Moderna and Pfizer vaccines?
Moderna and Pfizer used an atypical approach when synthesising their COVID-19 jabs.
Traditional jabs inject viruses, alive or dead into the bloodstream with a host of ingredients to produce an immune response.
But the new COVID-19 vaccines rely on prompting action from messenger RNA, a type of nucleic acid.
Otherwise known as mRNA, messenger RNA prompts a genetic mechanism which builds COVID antibodies and destroys traces of the virus without the need for a direct injection of viral matter.
The latest approach diverges from the norm both by mechanism and development time, as traditional vaccines take years to develop.
While the highly effective mumps vaccine took four years to develop, the COVID-19 jabs took less than one.
One of the reasons comes down to ingredients, as mRNA vaccines miss one classic jab constituent.
The exact combination of these ingredients and whether production includes others, depends on the company and disease.
As well as having several constituent ingredients, scientists also use others to manufacture a jab, such as eggs.
Eggs help to incubate a vaccine, which prolongs the process.
The mRNA vaccines don't require eggs or other ingredients, meaning it doesn't take as long to finish making them.
Vaccine manufacturers have not yet released the full array of ingredients their jabs use.
First, they will need to get their vaccines certified, during which independent organisations will evaluate the safety and efficacy of their products.
Preliminary research shows they are at least safe, however, with no safety concerns reported in neither Moderna nor Pfizer's trials.
They noted some side effects, such as pain at the injection site, muscle aches and headaches, however.