We’ll show here the information we obtain about the various vaccines under consideration.
Here’s a great explainer on the different methods being used by the leading vaccines and possibly soon-to-be vaccines.
AstraZeneca/Oxford
Approved in the UK but not yet in the US.
Two doses, some debate about how far apart, and some uncertainty about optimum strength of each dose.
Safety and efficacy of the ChAdOx1 nCoV-19 vaccine (AZD1222) : An “interim analysis” of this trial.
Johnson and Johnson (Janssen)
This is the third vaccine to be approved in the US, and distinctive for only requiring one shot rather than two. Doesn’t require special/very cold storage. Seems to be somewhat less effective than the Pfizer and Moderna vaccines, but might be more effective with the growing number of virus variants.
It is an adenovirus – a type of virus that causes the common code, modified to include some Covid DNA, and inactivated so you won’t catch either a cold or Covid.
More details here.
Moderna
The second to be approved in the US. An mRNA type vaccine. Requires cold storage (-4°F – most regular freezers can go down this low) and must be used within 30 days of thawing and being kept at fridge type temperatures.
Two doses, 28 days apart.
Here is a series of fact sheets and resources.
Pfizer/BioNTech
The first to be approved in the US. An mRNA type vaccine. Requires the coldest storage temperatures (-94°F – need special storage) and must be used within five days.
Two doses, a minimum of 21 days apart – do not take the second dose in less than 21 days, see for example, point 6 here. It is not known how much longer than 21 days is acceptable, and Pfizer says they’ve not tested extended gaps between the first and second dose.
This presentation, on slide 4, suggests the second dose has a window of four days – ie from 17 to 25 days – during which it can be given.
Safety and Efficacy of the BNT162b2 mRNA Covid-19 Vaccine : A study/review of their trial.