A press embargo means that a journal article, research study content, announcement or other news item cannot be publicized in any way until a specified date and time, typically dictated by the source of the information. For medical and other scientific studies, the release date usually is the date of publication.
Deeper Dive
An embargo provides journalists extra time to do sufficient reporting and write the article before the information becomes public knowledge. The value of advance access is that it potentially reduces mistakes as journalists rush to be the first to report the news. Organizations usually require journalists to agree to the embargo, which allows them (except in highly unusual situations) to seek outside comment but not to distribute the information widely or to anyone with a relevant investment stake (including the journalist, especially in cases where insider trading may be an issue). Breaking an embargo can get a journalist barred from receiving future embargoed content from that source. The statement “For Immediate Release” at the top of a press release, email, study or other news item means the information is NOT embargoed (except in cases where the source makes a mistake).