The director of US National Institutes of Health (NIH), Dr. Francis Collins, has said that NIH scientists played "a major role" in developing Moderna Inc's (Nasdaq:MRNA) COVID-19 vaccine and the agency intends to defend its claim as co-owner of patents on the shot, Reuters news agency reported on Thursday.

Moderna reportedly excluded three NIH scientists as co-inventors of a central patent for the company's COVID-19 vaccine in its application filed in July 2021.

NIH has asserted that three of its scientists, Dr John Mascola, Dr Barney Graham and Dr Kizzmekia Corbett, helped design the genetic sequence used in Moderna's vaccine and should be named on the patent application.

Collins said the NIH has been trying to resolve the patent conflict with Moderna amicably for some time and has failed.

In a statement emailed to Reuters, Moderna acknowledged that scientists at NIH's National Institute of Allergy and Infectious Diseases (NIAID) played a "substantial role" in developing Moderna's messenger RNA (mRNA) vaccine, but the company said it disagrees with the agency's patent claims.

In its statement, Moderna said: "We do not agree that NIAID scientists co-invented claims to the mRNA-1273 sequence itself. Only Moderna's scientists came up with the sequence for the mRNA used in our vaccine."

Moderna said the company has acknowledged NIH scientists in other patent applications, such as those related to dosing. But for the core patent, Moderna is only required to list Moderna scientists as inventors of the sequence under the strict rules of US patent law.