Depends on which schools to which you’re applying.
The UCs? Many of the UTs? Top 20s? Yes. Research is generally important and how important depends on the specific school. Consult MSAR or school-specific websites to see how important.
In general? Less important than clinical hours, leadership, and non-clinical volunteering across a majority of schools.
Indeed, it’s also possible for too much to be detrimental. If you have, for example, 3000 hours in research, three publications, and a conference talk versus 120 clinical hours on your application, admissions committees may question why you want to become a doctor and not a researcher (excluding MD/DO + PhD programs). That’s not good.
Research is a good thing to have, but it shouldn’t be at the very top of your priority list.
More to the point, and to answer your question specifically, publications are not common among medical school applicants. Additionally, there is much data on this. There is another thread on this that came through recently in which the amount of medical matriculants with research experience was examined. I’ll link it later if I run into it again.