Covid-19 vaccine maker Moderna is suing Pfizer and the German drug manufacturer BioNTech, accusing its main competitors of copying Moderna’s technology in order to make their own vaccine.

Moderna said Pfizer and BioNTech’s vaccine Comirnaty infringes on patents Moderna filed several years ago protecting the technology behind its preventive shot, Spikevax.

The company filed patent infringement lawsuits in both US federal court and a German court.

Pfizer spokeswoman Pam Eisele said the company had not fully reviewed Moderna’s lawsuit but was surprised by it, given that their vaccine is based on proprietary technology developed by both BioNTech and Pfizer.

She said the company would “vigorously defend” against any allegations in the case.

BioNTech said in a statement that its work was “original” and that it too would defend itself.

Moderna and Pfizer’s two-shot vaccines both use mRNA technology to help patients fight coronavirus.

“When Covid-19 emerged, neither Pfizer nor BioNTech had Moderna’s level of experience with developing mRNA vaccines for coronaviruses,” the company said in a complaint filed on Friday in the US District Court for the District of Massachusetts.

The mRNA vaccines work by injecting a genetic code for the spike protein that coats the surface of the coronavirus.

That code, the mRNA, is encased in a little ball of fat, and instructs the body’s cells to make some harmless spike copies that train the immune system to recognise the real virus.

That approach is radically different to how vaccines have traditionally been made.

Moderna said it started developing its mRNA technology platform in 2010, and that helped the company quickly produce its Covid-19 vaccine after the pandemic arrived in early 2020.

By the end of that year, US regulators had cleared shots from both Pfizer and Moderna for use after clinical research showed that both were highly effective.

Moderna chief executive Stephane Bancel said in a prepared statement that the vaccine developer pioneered that technology and invested billions of dollars in creating it.

Moderna worked with scientists at the National Institutes of Health to test and develop its Covid-19 vaccine.

The company said its lawsuit is not related to any patent rights generated during that collaboration.

The firm said it believes its rivals’ vaccine infringes on patents Moderna filed between 2010 and 2016.

Moderna said in its complaint that Pfizer and BioNTech copied some critical features of its technology, including making the “exact same chemical modification to their mRNA that Moderna scientists first developed years earlier” and went on to use in Spikevax.

Moderna said it recognises the importance of vaccine access and is not seeking to remove Comirnaty from the market.

It is also not asking for an injunction to prevent future sales.

Moderna said in 2020 that it would not enforce its Covid-19 related patents while the pandemic continued.

But the company said in March, with vaccine supplies improving globally, that it would update that pledge.

It said it still would not enforce its patents for vaccines used in low and middle-income countries.

But it expected companies such as Pfizer and BioNTech to respect its intellectual property, and it would consider “a commercially reasonable licence” in other markets if they requested one.

“Pfizer and BioNTech have failed to do so,” Moderna said in a statement.

The vaccines have swiftly become top-selling products globally.

Pfizer’s Comirnaty brought in more than 36 billion dollars (£30 billion) in sales globally last year, and analysts expect it to bring in nearly 33 billion dollars (£28 billion) this year, according to FactSet.

Moderna booked 17.6 billion dollars (£14.9 billion) in revenue from its vaccine last year.

Analysts project more than 21 billion dollars (£17.8 billion) in 2022.

Spikevax is Moderna’s only product on the market, but it is developing other vaccines using the mRNA technology.

The stock of the company, based in Cambridge, Massachusetts, trades publicly under the ticker symbol MRNA.