UPDATE 1-Germany's Merck boosts BioNTech lipid supply amid vaccine shortages

* Merck says lipids urgently needed for mRNA vaccines

* Acuitas, Polymun say they supply lipids to BioNTech

* EU Commission flagged concerns over lipid shortage (Adds background on lipids)

FRANKFURT, Feb 5 (Reuters) - Germany’s Merck KGaA is to boost its supply of lipids to biotech firm BioNTech to ease a shortage of a key ingredient in some COVID-19 vaccines as countries struggle to ramp up their programmes to tackle the pandemic.

Lipids, which are used to encapsulate messenger RNA molecules to help them reach the designated cells in the human body, have been in short supply as BioNTech, partnering with Pfizer, and rival Moderna try to boost vaccine output.

“Merck, in close collaboration with BioNTech, will significantly accelerate the supply of urgently needed lipids and increase the amount of lipid delivery towards the end of 2021,” Merck said in a statement on Friday.

Concerns over shortages have already been raised in the European Union, whose vaccination campaign has hit snags.

EU Commission President Ursula von der Leyen told a group of EU lawmakers on Tuesday that limited availability of lipids and other raw materials posed a constraint in COVID-19 vaccine production, according to minutes of the meeting seen by Reuters.

Merck’s CEO Stefan Oschmann told Reuters it would deliver several hundred kilograms, but he could not say how many doses of vaccine that would translate into.

Canada’s Acuitas Therapeutics and Austria’s Polymun have previously said they were working on lipids for BioNTech, which declined to comment on its suppliers.

A spokeswoman for BioNTech said Merck’s support had been taken into account for a global delivery target of 2 billion doses this year previously set by it and Pfizer.

Oschmann said Merck’s work was complementary to BioNTech’s other lipid suppliers.

“Only very few companies in the world are currently able to produce custom lipids in significant quantities and according to the highest quality requirements needed for vaccine production,” the German company said. (Reporting by Ludwig Burger, Patricia Weiss and Francesco Guarascio; Editing by Thomas Seythal and Alexander Smith)