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The Moderna v Pfizer-Biontech COVID-19 vaccine dispute: a brief explanation

Posted: 30/11/2022

Moderna’s patent infringement claim against Pfizer and BioNTech about its COVID-19 vaccine technology has been widely reported. After filing lawsuits in August 2022 in the US and Germany, Moderna has now launched related proceedings[1] in the UK Patents Court. In response, Pfizer and BioNTech have issued separate UK claims[2] that Moderna’s patents are invalid and should therefore be revoked.

This article discusses the issues in the UK proceedings, although it is to be expected that similar arguments will arise in the US lawsuit.


Moderna made headlines in October 2020 when it issued a 'patent pledge' which stated that it would not enforce its COVID-19 related patents against those making vaccines intended to combat the pandemic 'while the pandemic continues'. In March 2022, Moderna issued a revised version of the pledge that limited it to companies manufacturing in or for 92 low- and middle-income countries, thus signalling its intention to enforce its rights in higher-income territories such as the USA and Europe.

Unusually for a patent infringement case, Moderna is not requesting a court order to prevent Pfizer and BioNTech from selling its vaccine. Instead, it has requested 'payment of appropriate compensation... in lieu of an injunction' together with a damages payment for sales of Pfizer’s competing product which, given the global sales of the product, could be a huge sum.

The differing technologies

The patent cases concern Pfizer and BioNTech’s Cominarty® COVID-19 vaccine which was authorised before Moderna’s Spikevax® in both the UK and the USA. Both vaccines work by using messenger RNA (mRNA) to create an immune response against the virus that causes COVID-19. They are the first vaccines to be authorised using this new mRNA technology.

Most traditional vaccines work by introducing weakened or inactivated viruses or virus proteins to the body, triggering the immune system to respond. In contrast, mRNA vaccines work by providing the 'code' for cells to make copies of viral proteins - or fragments of those proteins - triggering an equivalent immune response.

A significant advantage of this approach is that, because no potentially infectious material is introduced to the body, the vaccine is safer. In addition, the mRNA degrades naturally so no additional or potentially toxic chemicals are needed to inactivate the vaccine. The technology can also be used to manufacture and modify vaccines more quickly than conventional techniques.

In addition to vaccines, mRNA technology shows significant promise as a therapy for other diseases such as cancer as it can be used to deliver tailored proteins directly into cells.

What are coronaviruses?

Coronaviruses are named for the crown-like protrusions or ‘spikes’ on their surface. These spike proteins mediate entry of the virus into host cells, which is necessary for the virus to replicate.

There are four main types of coronavirus. SARS-CoV-2, the virus which causes COVID-19, is a new member of the group of 'beta' coronaviruses which includes the viruses that cause Middle East respiratory syndrome (MERS) and severe acute respiratory syndrome (SARS).

mRNA technology: Moderna’s infringement claim

Moderna is asserting its patent rights in respect of three elements of the Cominarty® vaccine:

  • Use of lipid nanoparticles to encapsulate mRNA

The vaccine mRNA must be delivered inside cells for protein synthesis to occur. One way of achieving this is to encapsulate the mRNA strands in tiny bubbles of fat, known as lipid nanoparticles. This is the method used for Cominarty®.

Moderna has asserted that the formulation of the lipid nanoparticles used in Cominarty®, in particular the types and ratios of lipids used, infringes its patent rights.

  • Replacement of uracil with N1-methylpseudouridine in the vaccine mRNA

Early attempts to deliver mRNA into cells were limited by the inherent instability of mRNA and concerns about allergic reactions to it. In the mid-2000s, it was discovered that modifying uracil, one of the four building blocks of RNA, to create an analogue called pseudouridine significantly improved the stability and safety of mRNA.  

Moderna has claimed that the mRNA in Cominarty® contains N1-methylpseudouridine in place of the uracil building blocks. In turn, Pfizer and BioNTech’s case is that this technique to stabilise mRNA was well known and therefore obvious to do at the relevant time, particularly in light of the work of Katalin Karikó, an eminent mRNA research scientist who is now at BioNTech.

  • Use of mRNA which codes for the SARS-CoV-2 spike (S) protein

Cominarty® contains mRNA strands which code for the entire spike protein of the COVID-19 virus. Moderna is asserting that this infringes its patent rights which cover (in part) a 'betacoronavirus mRNA vaccine' encoding the coronavirus spike protein.

Pfizer and BioNTech’s position is that, given the previous work on MERS and SARS, the spike protein was well known to be a primary target for vaccine development for a betacoronavirus.

The patents asserted by Moderna in the US and UK proceedings claim these elements either individually or in combination. There are three US patents asserted in the US infringement claim. For the UK proceedings, the relevant patents are EP (UK) 3590949 (concerning the replacement of uracil in mRNA) and EP (UK) 3718565 (concerning a betacoronavirus mRNA vaccine encoding the spike protein, formulated in a lipid nanoparticle comprising four types of lipid molecule).

Implications for mRNA technology

As Moderna’s patents relate to the fundamental principles of mRNA technology, they are likely to apply to future developments in mRNA vaccines and therapeutics. This is a rapidly developing area of medicine, with mRNA vaccines currently in development for conditions such as influenza, rabies and respiratory syncytial virus (RSV).

An analysis of the market for mRNA technology published last year revealed that more than 30 biopharma companies were working on mRNA vaccines and/or therapeutics last year. If the patents are upheld, they could provide a lucrative future revenue stream for Moderna. With such high stakes, these claims are likely to be fiercely fought.

Moderna is also facing claims relating to mRNA technology from Alnylam Pharmaceuticals, Arbutus Biopharma and Genevant Sciences. CureVac, a German pharmaceutical company, has also launched proceedings against Pfizer and BioNTech for alleged infringement of four of its patents relating to lipid nanoparticle technology.


[1] Case No. HP-2022-000022

[2] Case No. HP-2022-000027

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