One year since the WHO declared a pandemic, Europe now has four COVID-19 vaccines approved for use. While challenges remain in manufacturing and distributing millions of doses of vaccine, the news is the latest sign of progress in the long battle against the virus.
Europe’s medicine and vaccine regulator, the European Medicines Agency (EMA), recommended granting a conditional marketing authorisation for the COVID-19 Vaccine Janssen in adults of all ages. The watchdog said its thorough evaluation concluded that the single-dose vaccine met the criteria for safety, efficacy and quality.
‘With this latest positive opinion, authorities across the European Union will have another option to combat the pandemic and protect the lives and health of their citizens,’ said Emer Cooke, EMA’s Executive Director, adding, ‘this is the first vaccine which can be used as a single dose’.
The vaccine is already in use in the United States, South Africa and several other countries. The EU has ordered 400 million doses of the jab which will be delivered in stages. The first 200 million are expected in 2021 with deliveries due to arrive in European countries in the coming weeks. The vaccine can also be stored in a refrigerator and be transported at 2°C to 8°C for a single period of up to 3 months.
Results from a clinical trial involving people in the United States, South Africa and Latin American countries found that the vaccine was effective at preventing symptomatic COVID-19 in people from 18 years of age. This study involved over 44,000 people. Half received a single dose of the vaccine and half were given placebo (a dummy injection). People did not know if they had been given COVID-19 Vaccine Janssen or placebo.
The trial found a 67% reduction in the number of symptomatic COVID-19 cases after 2 weeks in people who received the vaccine (116 cases out of 19,630 people) compared with people given placebo (348 of 19,691 people). This means that the vaccine had a 67% efficacy.
The side effects with COVID-19 Vaccine Janssen in the study were usually mild or moderate and cleared within a couple of days after vaccination. The most common ones were pain at the injection site, headache, tiredness, muscle pain and nausea.
The safety and effectiveness of the vaccine will continue to be monitored as it is used across the EU, through the EU pharmacovigilance system and additional studies by the company and European authorities.
How COVID-19 Vaccine Janssen works
COVID-19 Vaccine Janssen works by preparing the body to defend itself against COVID-19. It is made up of another virus (an adenovirus) that has been modified to contain the gene for making the SARS-CoV-2 spike protein. This is a protein on the SARS-CoV-2 virus which it needs to enter the human body’s cells.
The adenovirus passes the SARS-CoV-2 gene into the vaccinated person’s cells. The cells can then use the gene to produce the spike protein. The person’s immune system will recognise the spike protein as foreign and produce antibodies and activate T cells (white blood cells) to target it.
Later, if the person comes into contact with SARS-CoV-2 virus, the vaccinated person’s immune system will recognise the spike protein on the virus and be ready to defend the body against it.
The adenovirus in the vaccine cannot reproduce and does not cause disease.
(Vaccines Today is funded by Vaccines Europe, a trade association whose members include Pfizer, Moderna, AstraZeneca & Janssen.)
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This article was updated on 11 October 2021