Each dose of Pfizer has a long and complex path involving mixing, storage at temperatures colder than the South Pole and specific protocols that must be followed before it becomes a jab.

Each dose of Pfizer vaccine has a long and complex path involving mixing, storage at temperatures colder than the South Pole and specific protocols that must be followed before it becomes a jab.

Various companies use different ingredients and different delivery systems in their COVID-19 vaccines. Researchers are investigating whether it's better for individuals to mix what's available.

Recently in the spotlight for its role in the Pfizer and Moderna COVID-19 vaccines, mRNA is not a new invention. It's a crucial messenger molecule at work every day in every cell in your body.

So far, most vaccines in the US are mRNA vaccines. These represent a new technology and are likely to take over the vaccine world. But how do they work? What are their weaknesses? Five experts explain.

A biologist explains what proteins do in viruses, how they interact with human cells, how the vaccine delivers mRNA into the cell and how antibodies protect us.

Two pharmacists involved in COVID-19 vaccine preparation explain the role pharmacists are poised to play in expanding vaccine access.