The European Medicines Agency (EMA) has said it hopes to be able to approve the Russian Sputnik V vaccine for use in Europe's vaccine roll-out.
EMA Executive Director Emer Cooke told a European Parliament committee this morning: "We do hope this will be a valuable vaccine to add to the vaccines that are available for the EU population and that it will get an authorisation at European level based on the same standards of safety, quality and efficacy that we apply for every vaccine."
She said the EMA had been in discussion with the company and was currently carrying out a "rolling" review of the vaccine, and was carrying out inspections of the facility producing it.
The EMA is also evaluating the Novax and CureVac vaccines, as well as looking at companies producing so-called monoclonal antibody medicines, such as Eli Lilly, Regeneron and Celltrion, which can treat Covid-19 patients.
The EMA approved the Jansen (Johnson & Johnson's) single dose vaccine on 11 March and said it should become available for distribution in April.
Addressing the parliament's health committee, Ms Cooke reiterated that the risk of blood clots associated with the AstraZeneca vaccine was, so far, determined to be lower than would be expected in the overall population.
However, she said that during investigations into the issue, the EMA's risk committee had found a small number of cases of "rare, unusual, but potentially very serious clotting disorders, and some of these had a fatal outcome".
She said this had prompted the agency to "take a closer look" and to call for more clinical and laboratory information from member states.
Ms Cooke said that based on the information so far, "we are not in a position to definitively rule out a link between the vaccine and these cases, and we are therefore at a point where we need to launch additional investigations to understand more".
She said the EMA's safety committee has recommended raising awareness of the risks by making sure they were included in the vaccine product information and by drawing attention to "these possibly rare conditions" so that healthcare professionals and those already vaccinated would be able to spot signs and symptoms, and to "help manage any possible effects".
She told MEPs: "This is not an unexpected situation. When you vaccinate millions of people it's inevitable that rare or serious instances of illnesses will be detected after vaccination."
Ms Cooke said the EMA would be able to speed up the authorisation process for any new vaccines that had been produced in order to adapt to new Covid-19 variants, and to have multiple variants dealt with under one market authorisation, as is the case with annual flu vaccines.
She said the EMA had approved the practice of securing six, and possibly seven doses, from a Pfizer/BioNTech vial, but that in order to put this information on labels it was important to ensure that medical professionals administering the jabs were able to "consistently" get seven doses in every vial.
She said with the Moderna vaccine, the EMA was looking at data that would indicate the ability to get 11 doses from a ten-dose vial.
However, she urged countries to continue the roll out of vaccine programmes.
She said: "We have to continue not to lose sight of the fact that vaccines will help us to control this pandemic.
"We see already early observational studies particularly from Israel and the UK which indicate that infection rates are falling and that the spread of the disease can be reduced when vaccination rates in the population are high."
EU vaccine target requires 255 million doses - Gallina
Meanwhile, the European Commission's chief vaccine negotiator Sandra Gallina said that Europe should be able to meet its target of vaccinating 70% of all those aged over 18 by the end of the summer.
She told the European Parliament's budgetary control committee that the target would require 255 million vaccine doses and that this was "achievable".
Ms Gallina was highly critical of AstraZeneca, which she said had caused reputational damage for the EU.
She said the company had been contracted to deliver 300 million doses to member states, but had not even delivered "one quarter" of that amount.
The EU had issued a letter of formal notice to the company, the first step in legal proceedings, she said.
"This is an issue which cannot be left unattended," she told MEPs. "We will use all the tools at our disposal to get doses."
Ms Gallina said that when the European Commission negotiated contracts with pharmaceutical companies last year, they did so through advance purchasing agreements, meaning that they were paying for vaccines which did not yet exist.
She said the "trend" among member states at the time was to order fewer vaccines than might be allocated through a pro-rata distribution mechanism, because the vaccines had not yet existed.
Other member states had agreed to "soak up" any excess doses from those allocations not taken up by member states.
It is understood this was done so as to ensure that the overall numbers in the contract did not fall, and thus push up the price of the doses.
Ms Gallina told MEPs that the European Commission was still using its export authorisation scheme, which has so far prevented one shipment of AstraZeneca doses going from Italy to Australia.
The option of further export blocks was on the table, she said.
This week an AstraZeneca facility in the Netherlands, run by Halix, a contractor, is due to be approved by the EMA, meaning it will be able to start distributing millions of vaccine doses.
However, due to the ongoing row between the company, the EU and UK over the shortfall in doses for Europe, the Dutch government is expected to alert the European Commission to any move by Halix to ship the AstraZeneca doses to the UK.
The UK has sent Tim Barrow, a former ambassador to the EU, to Brussels for negotiations with the European Commission and AstraZeneca on how to resolve the standoff over vaccine supplies.
The EU believes that AstraZeneca has fulfilled its contracts to the UK at the expense of the EU, which has received vastly smaller amounts of vaccine doses than what was contracted for.