NEW YORK, May 16 (Reuters) - Maravai LifeSciences Holdings Inc, a provider of capping reagents for COVID-19 vaccines whose shares plunged after the pandemic eased, has attracted private equity interest, people familiar with the matter said.

Buyout firm Thomas H. Lee Partners has approached Maravai, which has a market capitalization of about $3.8 billion, with a non-binding offer, the sources said. The price offered could not be learned.

Maravai rejected the offer, and there is no certainty that a new bid will follow or that any deal will be reached, the sources added.

Nevertheless, the acquisition approach shows how Maravai has become a takeover target after it lost three-quarters of its value from its August 2021 peak, when the scramble to develop COVID-19 vaccines using mRNA technology buoyed its reagent business. Since then, Maravai has been trying to pivot to other mRNA-based vaccines.

The sources requested anonymity because the matter is confidential. Spokespeople for Maravai and Thomas H. Lee Partners did not respond to requests for comment.

Maravai last week revised its 2023 revenue guidance down by $20 million to between $400 million and $440 million, about half what it generated in 2022. The San Diego-based company blamed a "sluggish" biotech market for the slowdown.

Following the success of COVID-19 vaccines, drugmakers are racing to apply mRNA technology in the development of other vaccines, including for cancer and tuberculosis. Maravai has been positioning to capture market share when production of these vaccines takes off in the next few years.

Maravai rejected a $42 per share all-cash offer from laboratory supplies vendor Sartorius AG in February 2022 as inadequate, Reuters reported at the time. Maravai shares have since dropped and ended trading on Monday at $15.

Maravai has also struggled with its CEO succession planning. It tapped former Danaher Corp executive Trey Martin as chief executive in October, but Danaher sued claiming a breach of his non-compete agreement.

Maravai settled with Danaher by agreeing to delay Martin's appointment and preclude his involvement in its nucleic acid production operations until the end of July. Maravai co-founder and executive chairman Carl Hull is currently serving as interim CEO. (Reporting by Greg Roumeliotis in New York Editing by Anirban Sen and Mark Potter)