By Jonathan Corum and Carl ZimmerUpdated May 7, 2021
The University of Oxford partnered with the British-Swedish company AstraZeneca to develop and test a coronavirus vaccineknown as ChAdOx1 nCoV-19 or AZD1222. A large clinical trial showed the vaccine offered strong protection, with an overall efficacy of 76 percent.
A Piece of the Coronavirus
The SARS-CoV-2 virus is studded with proteins that it uses to enter human cells. These so-called spike proteins make a tempting target for potential vaccines and treatments.
Some of the spike proteins produced by the cell form spikes that migrate to its surface and stick out their tips. The vaccinated cells also break up some of the proteins into fragments, which they present on their surface. These protruding spikes and spike protein fragments can then be recognized by the immune system.
The cell sends out warning signals to activate immune cells nearby. By raising this alarm, the Oxford-AstraZeneca vaccine causes the immune system to react more strongly to the spike proteins.