Whidbey Island health officials are reporting 27 cases of whooping cough, or pertussis, as of Thursday morning.

Most of the new cases are concentrated on the South End, said Island County Medical Officer Dr. Roger Case.

All adults from age 12 to 64 should be administered a Tdap vaccine — which covers tetanus and pertussis — every 10 years.

For more information, visit www.islandcounty.net/health/pertussis. All cases of pertussis should be reported to the Island County Health Department immediately at 360-679-7350.