AstraZeneca's COVID-19 vaccine, Vaxzevria (ChAdOx1-S [Recombinant]), has been granted approval in the European Union by the European Medicine Agency (EMA) as a third dose booster in adults.
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Healthcare professionals can now use Vaxzevria as a third dose booster in patients previously given a primary vaccine schedule of either Vaxzevria or an EU-approved mRNA COVID-19 vaccine.
The authorisation is based on a review by the Committee for Medicinal Products for Human Use (CHMP) of the substantial body of evidence demonstrating an increased immune response after a third dose booster with Vaxzevria following a primary vaccine schedule of either Vaxzevria or an mRNA COVID-19 vaccine.
Although more than 65% of the global population has received at least one dose of a COVID-19 vaccine, there remains a significant challenge to ensure people receive both their primary vaccine schedule and third dose booster, and healthcare professionals now have greater flexibility in their choice of vaccine.
There is a substantial body of evidence supporting Vaxzevria as a third dose booster following all primary vaccination schedules tested to date including Vaxzevria, mRNA vaccines, and CoronaVac.
Vaxzevria is already authorised as a homologous booster (patients previously given a primary vaccine schedule of Vaxevria) in the UK, and several countries in Asia and Latin America.
It has also been authorised as a heterologous booster (patients previously given a primary vaccine schedule of either a viral vector vaccine other than Vaxzevria or an inactivated vaccine or an mRNA COVID-19 vaccine) in a number of non-EU countries.
AstraZeneca COVID-19 vaccine was invented by the University of Oxford.
It uses a replication-deficient chimpanzee viral vector based on a weakened version of a common cold virus (adenovirus) that causes infections in chimpanzees and contains the genetic material of the SARS-CoV-2 virus spike protein. After vaccination, the surface spike protein is produced, priming the immune system to attack the SARS-CoV-2 virus if it later infects the body.
Vaxzevria is a ‘viral vector’ vaccine, which means a version of a virus that cannot cause disease is used as part of the vaccine, leaving the body knowing how to fight it if it is exposed to the real virus later. This vaccine technology has been used by scientists over the past 40 years to fight other infectious diseases such as the flu, Ebola, and HIV.
The vaccine has been granted a conditional marketing authorisation or emergency use in more than 125 countries. It also has Emergency Use Listing from the World Health Organization, which accelerates the pathway to access in up to 144 countries through the COVAX Facility.
Under a sub-license agreement with AstraZeneca, the vaccine is manufactured and supplied by the Serum Institute of India under the name COVISHIELD. ■