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Although the shot has been shown to be effective and safe in clinical trials, its place of manufacture can influence whether a country considers it valid for entry.
The vaccine is known as Vaxzevria when made in Europe, but doses produced by Serum Institute of India carry the Covishield brand.
The European Medicines Agency has yet to approve Covishield. This has created hurdles for travellers wishing to visit many EU member states.
What is Covishield?
Like the European-made version of the Oxford-AstraZeneca vaccine, it consists of a harmless version of a type of virus called an adenovirus that normally infects chimpanzees.
This adenovirus has had genetic material from the coronavirus added to it. When the vaccine enters the human body, the recipient’s cells produce spike proteins like those of the coronavirus. This teaches the immune system to recognise them and respond should the individual subsequently be exposed to the virus.
Which organisations have approved Covishield?
India’s Central Drugs Standard Control Organisation granted approval for some emergency use of Covishield in January.
The following month, the World Health Organisation gave emergency use authorisation for the Oxford-AstraZeneca vaccine, whether manufactured in Europe or in India. This includes SII-made doses.
Britain’s Medicines and Healthcare products Regulatory Agency (MHRA) also approved the use of the Indian-made doses.
But the EMA – the EU’s regulator – has not, so some countries in the bloc do not accept vaccination with Indian-made vaccines for entry.
Last month it was reported that a British couple were prevented by their airline from travelling to Malta because they had received the Covishield vaccine rather than Vaxzevria.
The UK transport secretary, Grant Shapps, later tweeted that the Maltese had changed their travel advice to prevent similar incidents.
Why hasn’t the EMA approved the Indian-made doses?
The EMA’s failure to approve the SII as an alternative manufacturer of the Oxford-AstraZeneca shot appears to be simply a “licensing/bureaucratic issue”, said Prof David Taylor, professor emeritus of pharmaceutical and public health policy at University College London.
He said hurdles had arisen because of the speed at which Covid-19 vaccines have been developed and approved, and that there was no indication of safety concerns about the Indian vaccine.
“It’s all a function of it being an emergency situation. I wouldn’t blame anybody,” he said. “It’s quite right we worry about safety and we want things to be licensed by the [appropriate] licensing authority.”
Prof Paul Hunter, an infectious diseases specialist at the University of East Anglia in the UK, said there was “no public health issue” with the Indian-manufactured doses.
“As far as I’m aware, there’s no indication at all that the Indian-made AstraZeneca vaccine doesn’t work just as well as that made in Europe,” he said.
He said that drugs from some countries might not be approved if counterfeiting was suspected, but that this was not a concern with the Indian-made vaccine.
What is the current situation for travel to and within Europe?
The EU has a Digital Covid Certificate for travel within the 27 EU nations and six other places – Iceland, Liechtenstein, Norway, San Marino, Switzerland and Vatican City.
The European Commission states that: “Member states will have to accept vaccination certificates for vaccines which received EU marketing authorisation.”
This means they are not obliged to accept the Indian-made shots, and participating nations are applying the same rules for visitors from outside Europe.
But the EC also says that member states “may decide” to accept other vaccines. About half of the countries that are part of the EU Digital Covid Certificate have approved the Indian-made Oxford-AstraZeneca shots.
Covishield is now accepted by, among others, Austria, Bulgaria, France, Germany, Iceland, Spain, Sweden and Switzerland.
But about a dozen European countries are waiting for the green light from the EMA, so Covishield-vaccinated visitors to Portugal, for example, may need to quarantine on arrival.