Health officials in B.C.'s Fraser Valley are urging people to get vaccinations for whooping cough as the disease continues to spread in the region.

The Fraser Health Authority says there have been more than 150 suspected or confirmed cases of the illness since early December, mostly in the Hope, Chilliwack, and Agassiz areas, but the disease is spreading to other communities.

It also says the real number of cases is probably much higher because not all are reported.

The best protection against whooping cough is to get vaccinated, especially if people have close contact with infants and young children, said Chief Medical Health Officer Dr. Paul Van Buynder.

"Now we have seen transmission of cases in Maple Ridge, in Langley, in Surrey and in Mission," Van Buynder told CBC News late Thursday. "Because we are seeing evidence of transmission and we have had a child from outside Fraser East, we have decided to expand the response to incorporate the whole of the Fraser Valley."

Van Buynder said adults who were vaccinated as children should have a booster shot, while parents should ensure their children are also vaccinated.

Whooping cough is a contagious disease that causes severe coughing that may last for months and can be a serious illness in young children and babies, who have smaller airways.