Viral vector vaccines paused
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After reports of rare blood clotting, the U.S., EU and South Africa have paused the rollout of Johnson & Johnson’s coronavirus vaccine. The move follows similar cases after doses of AstraZeneca’s vaccine
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Protein stimulates human immune system to produce antibodies. If infected, antibodies
attack coronavirus
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Blood clots in veins of brain: Europe* detects 222 cases, including cerebral venous sinus thrombosis, out of 34 million injections. Six cases of CVST out of 6.8m shots in U.S.

Vein

Platelets: Form mesh with blood cells, proteins and fibrin to produce clot
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Viral vector vaccines
Use common-cold causing adenovirus – modified so it is unable to cause disease – as
vector to carry genetic instructions into human cells
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Gene
Human cell
Adenovirus
Gene creates viral protein on surface of cell Coronavirus
Antibodies
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*EU, Iceland, Norway, Liechtenstein and UK as of April 4, according to European Medicines Agency

Sources: AFP, European Medicines Agency, Johnson & Johnson © GRAPHIC NEWS