EMA ( European Medicines Agency ) has recommended granting a conditional marketing authorisation for COVID-19 Vaccine AstraZeneca to prevent coronavirus disease 2019 ( COVID-19 ) in people from 18 years of age.
This is the third COVID-19 vaccine that EMA has recommended for authorisation.
Combined results from 4 clinical trials in the United Kingdom, Brazil and South Africa have shown that COVID-19 Vaccine AstraZeneca was safe and effective at preventing COVID-19 in people from 18 years of age.
These studies involved around 24,000 people altogether. Half received the vaccine and half were given a control injection, either a dummy injection or another non-COVID vaccine.
People did not know if they had been given the test vaccine or the control injection.
The safety of the vaccine has been demonstrated across the four studies. However, the Agency based its calculation of how well the vaccine worked on the results from study COV002 ( conducted in the UK ) and study COV003 ( conducted in Brazil ).
The other two studies had fewer than 6 COVID-19 cases in each, which was not enough to measure the preventive effect of the vaccine. In addition, as the vaccine is to be given as two standard doses, and the second dose should be given between 4 and 12 weeks after the first, the Agency concentrated on results involving people who received this standard regimen.
These showed a 59.5% reduction in the number of symptomatic COVID-19 cases in people given the vaccine ( 64 of 5,258 got COVID-19 with symptoms ) compared with people given control injections ( 154 of 5,210 got COVID-19 with symptoms ).
This means that the vaccine demonstrated around a 60% efficacy in the clinical trials.
Most of the participants in these studies were between 18 and 55 years old.
There are not yet enough results in older participants ( over 55 years old ) to provide a figure for how well the vaccine will work in this group. However, protection is expected, given that an immune response is seen in this age group and based on experience with other vaccines; as there is reliable information on safety in this population, EMA’s scientific experts considered that the vaccine can be used in older adults.
More information is expected from ongoing studies, which include a higher proportion of elderly participants.
COVID-19 Vaccine AstraZeneca is given as two injections into the arm, the second between 4 to 12 weeks after the first.
The most common side effects with COVID-19 Vaccine AstraZeneca were usually mild or moderate and got better within a few days after vaccination.
The most common side effects are pain and tenderness at the injection site, headache, tiredness, muscle pain, general feeling of being unwell, chills, fever, joint pain and nausea.
The safety and effectiveness of the vaccine will continue to be monitored as it is used across the European Union ( EU ), through the EU pharmacovigilance system and additional studies by the company and by European authorities.
COVID-19 Vaccine AstraZeneca is expected to work by preparing the body to defend itself against infection with the coronavirus SARS-CoV-2. This virus uses proteins on its outer surface, called spike proteins, to enter the body’s cells and cause disease.
COVID-19 Vaccine AstraZeneca is made up of another virus ( of the adenovirus family ) that has been modified to contain the gene for making the SARS-CoV-2 spike protein.
The adenovirus itself cannot reproduce and does not cause disease.
Once it has been given, the vaccine delivers the SARS-CoV-2 gene into cells in the body. The cells will use the gene to produce the spike protein.
The person’s immune system will treat this spike protein as foreign and produce natural defences − antibodies and T cells − against this protein.
If, later on, the vaccinated person comes into contact with SARS-CoV-2, the immune system will recognise the virus and be prepared to attack it: antibodies and T cells can work together to kill the virus, prevent its entry into the body’s cells and destroy infected cells, thus helping to protect against COVID-19. ( Xagena )
Source: EMA, 2021