Parents who resist vaccinating their children could be partly to blame for an outbreak of measles in Metro Vancouver, according to local health authorities.

Cases of measles this year have skyrocketed compared to last year, said Dr. Victoria Lee, a medical health officer for Fraser Health Authority.

There have been about a dozen confirmed cases of measles in B.C. in 2013 so far compared to two all of last year, Lee said. Five of this year’s cases happened in the Fraser Valley.

“For measles, even one case is a serious number,” she said. “In most of the years we’ve had only zero to two cases in the Fraser region… so again, five is a significant concern for us.”

Last week, officials determined four people infected with measles in the Vancouver area were not immunized, incompletely immunized or did not know their immunization status.

It’s concerning to Fraser Health and Lee, who said immunization rates are not high enough and is urging parents to make sure their children are vaccinated.

She said vaccination rates have fluctuated between 60 per cent and 80 per cent over the last few years, and ideally 100 per cent of Fraser Valley residents would vaccinate.

“We need to do everything we can to increase immunization rates in those communities,” she said. “It’s absolutely incorrect that the measles vaccine can cause specific diseases.”

Measles is a highly infectious disease that can be transmitted by air, and can stay in the air up to two hours.

Lee said doctors are currently investigating other patients and fear the number of measles cases could rise.

While people born before 1957 are likely to be immune because outbreaks were once common, officials say individuals born after 1956 should receive two doses of the vaccine after the age of one.

Last month, the Fraser Health Authority staff had to contact the families of as many as 60 newborns and their mothers after they were exposed to the measles virus by a visitor to the Abbotsford Regional Hospital.

With files from CTV British Columbia's Mi-Jung Lee and The Canadian Press