WATCH | Pfizer's Covid-19 vaccine looks positive, but many questions remain
Pfizer has announced that initial data shows its Covid-19 trial vaccine is more than 90% effective. The vaccination consists of two injections 21 days apart and these types of vaccines are considered safe and easy to produce.
While this is great news, there are some grey areas.
Pfizer and BioNTech have chosen RNA messenger technology for their vaccine. It is made up of lab-made RNA strands containing the code for the same protein that allows the coronavirus to enter cells.
Each of these RNA strands is inserted into a lipid envelope injected into muscle cells. They programme them to produce the protein, which will trigger an immune response without triggering disease.
Beate Kampmann, head of the vaccine centre at the London School of Hygiene and Tropical Medicine, said it was exciting to see a vaccine produce results, but warned we are still to see how long a vaccine can protect someone from the coronavirus, given that the data from the study showed a test patient's positive status 28 days after volunteers received two injections.