The variables that were independently associated with a higher odds of headache in hospitalized COVID-19 patients were anosmia, myalgia, female sex, and fever; while the variables that were independently associated with a lower odds of having headache were age, modified Rankin scale, increased CRP on admission, abnormal platelet value on admission, lymphopenia on admission, and increased D-dimer on admission. This evidence concerns the gene CRP and Kallmann syndrome.