Securities fraud suits are multiplying over Johnson & Johnson’s alleged failure to disclose questions about the effectiveness of its decongestant products when it conducted an initial public offering for spinoff division Kenvue.

Kao v. Johnson & Johnson, filed Jan. 26 in Trenton, New Jersey, federal court, is the latest shareholder suit stemming from the Food and Drug Administration’s announcement that an ingredient called phenylephrine, widely used in decongestants, is ineffective.