WALTHAM — Shareholders of Alere Inc. voted overwhelmingly Friday to approve the $5.8 billion acquisition of the medical diagnostics company by Abbott Laboratories, but the transaction remains stuck in legal limbo.

In a nonbonding advisory vote, Alere investors also OK’d one-time payments to Alere’s top five executives totaling more than $39 million if the buyout is completed.

Chief executive Namal Nawana would receive nearly $20.5 million and chief financial officer James Hinrichs would get nearly $7.4 million under a “change of control’’ formula approved by the board of Waltham-based Alere.

Alere and Abbott, based outside Chicago, both say publicly they remain committed to the merger they announced Feb. 1. But Abbott has demanded information from Alere about three Justice Department inquiries that have come to light since the deal was unveiled.

Investigators are examining Alere’s billing to Medicare, the integrity of a product line, and its sales practices overseas, according to regulatory filings.

The parties are also engaged in a legal battle, with Alere suing Abbott for allegedly trying to back out of the deal so it can deploy its financial resources to acquire the larger St. Jude Medical Inc. Abbott has dismissed the allegations as fiction.

In a special meeting lasting less than 15 minutes, more than 98 percent of Alere shares were cast in favor of the proposed Abbott buyout. Investors cast 55 percent of the company’s shares in favor of the special compensation packages.

Fewer than 20 Alere executives, board members, and shareholders attended the meeting at Westin Waltham hotel. Nawana greeted those in attendance but did not discuss the Abbott merger or answer questions. Nearly all the votes were sent electronically.

Robert Weisman can be reached at robert.weisman @globe.com. Follow him on Twitter @GlobeRobW.