From BBC (story and charts here):
“The big three”
“The three vaccine frontrunners are those developed by Pfizer/BioNTech, Moderna and Oxford/AstraZeneca. Pfizer and Moderna have both developed RNA vaccines … [that] inject a tiny fragment of the virus’s genetic code into the body [which] starts producing part of the coronavirus and [gets] the body to mounts a defence. These have been approved for use in the UK, Europe and the US. The Oxford vaccine … uses a harmless virus to carry the same genetic material into the body. This has been approved in the UK and Europe. It is the easiest of the three to use as it can be stored in portable vaccine freezers, making it relatively easy to transport. All are supposed to be given as two doses ….
“The two new ones”
“Data from large-scale trials on two new vaccines have also been presented recently. The work by Janssen and Novavax will now be reviewed by drugs regulators before they can join the vaccination effort. Janssen’s vaccine uses the same technique as Oxford, but … is given as a single injection … [which] could make a significant impact around the world. Novavax [is] using a different, old-school, approach … [in which] proteins from the virus and a chemical to prime the immune system are injected into the body.
“What is the rest of the world doing?”
“There are other noteworthy vaccines [that] are not being used in Europe and the US. The Sinovac, CanSino and Sinopharm vaccines have been developed … in China and deals have [been] signed with other countries in Asia and South America. Around one million people in China are reported to have been given the Sinopharm injection. The Sputnik V vaccine, developed by Russia … has published early trial data saying it is effective and some people have been immunised.
“Are they all equally effective?”
“… [A]ll the main vaccines seem to have a large impact on your chances of needing hospital treatment or dying from Covid. [But] one of the most important questions — do they stop you [from] spreading the virus — remains unknown.
“What about [virus] variants?”
“New versions of the coronavirus are emerging …. [T]here is a warning sign in the data from Janssen and Novavax which have the first ‘real-world’ data on the new variants. Both showed a dip in their overall effectiveness in South Africa, where a new and worrying variant has been spreading. The results were still good and clearly better than no vaccine at all… [but] we may need to change the vaccines we use in the future. …
“What still needs to be done?”
- “Huge-scale manufacturing to produce billions of doses and distribute them around the world
- Research to find out how long protection lasts
- Research to discover what effect vaccine have on the spread of the virus”