The AstraZeneca-Oxford vaccine uses a weakened live pathogen. One drawback of recombinant adenoviral vector vaccines is that people may require booster shots over time. While recombinant vaccines are common, the only commercially available adenovirus-based vaccine of this type is a rabies vaccine for animals.

Is the mRNA COVID-19 vaccine a live vaccine?

mRNA vaccines are not live vaccines and do not use an infectious element, so they carry no risk of causing disease in the vaccinated person.

Is AstraZeneca COVID-19 vaccine approved by the FDA?

The AstraZeneca vaccine is not authorized for use in the U.S., but FDA understands that these AstraZeneca lots, or vaccine made from the lots, will now be exported for use.