The European Union has decided to exercise an option to purchase additional doses of the Comirnaty COVID-19 vaccine from Pfizer (NYSE:PFE) and BioNTech (NSDQ:BNTX). 

The two companies will deliver 600 million doses of the vaccine to the EU in 2021. 

The Continent’s mass-vaccination efforts have sputtered for much of early 2021, given supply constraints related to the AstraZeneca vaccine and, later, safety concerns related to rare blood clotting problems potentially linked to that vaccine. 

In related news, Sweden and several other EU nations are negotiating with Russia to procure that country’s Sputnik V vaccine. The idea behind those talks is to prepare for when the European Medicines Agency authorizes that vaccine. 

The EU nations Hungary and Slovakia had already obtained a substantial number of doses of the vaccine, but Russia had asked Slovakia to return hundreds of millions of doses earlier this month, citing contract violations, Reuters reported. 

Slovakia’s SUKL drug agency had decided that 200,000 doses of the vaccine should not be administered as the manufacturer had provided incomplete or inaccurate information. 

In particular, SUKL determined that the batches of vaccine did not match vaccine doses the EU regulator had reviewed.