Two unvaccinated children in B.C.'s Fraser Valley have contracted the extremely contagious measles virus, putting others in the community at risk.

The exposure occurred at a school in Chilliwack, B.C., in a community with traditionally low immunization rates, Fraser Health's Chief Medical Health Officer (CMHO) said in a statement released Saturday and updated Monday.

The potential for this virus to spread as a result is very concerning, the statement said.

Two confirmed cases have been reported in the city, approximately 100 kilometres east of Vancouver, but Fraser Health is following up as many as 100 suspected cases among children in the community.

"Vaccination coverage in the whole of British Columbia is appalling," CMHO Dr. Paul Van Buynder told CTV Vancouver. "It's nowhere near enough to protect the community and we need to do better as a group."

Vaccinations are rare in the area because of strong religious beliefs, CTV Vancouver's Mi-Jung Lee reported. Members of the Reformed Congregation of North America believe vaccinations expose the body to potential harm.

Mount Cheam Christian School closed early ahead of March Break when the two cases were reported. The father of the two children infected is also the principal of the school.

"We're working closely together with Fraser Health, the local health authority," Jan Neels told CTV Vancouver. He said the experience has not changed his mind about vaccines.

But Fraser Health said that the most effective protection against the virus is two doses of the vaccine, which is free to everyone born in or after 1957. Family doctors can administer the vaccine.

The provincial health minister told media he hopes the outbreak will encourage residents to listen to their healthcare providers and get vaccine rates up.

"That will protect the population in general," Terry Lake said.

The CMHO is advising families who may have been exposed to the virus to avoid travelling until they've been cleared.

Public health representatives are contacting families directly to offer an immunoglobulin vaccine in order to reduce the chance of the infection spreading.

If residents of the area suspect they've been exposed or develop any symptoms, Fraser Health advises them to see their doctor immediately, and to notify the office before arriving to help prevent the spread of the disease to others.

Symptoms of measles

The measles virus is very contagious and can be serious for those without immunizations, according to Fraser Health's website.

The virus spreads through the air when an infected person breathes, coughs or sneezes. Symptoms include:

Fever

Cough

Runny nose

Red and inflamed eyes

Rash starting on the face and neck, then spreading (lasts at least three days)

Other complications include pneumonia, and although it is uncommon, those who contract the virus may develop brain inflammation or damage, blindness and deafness. Approximately one in 3,000 cases is fatal.

With files from CTV Vancouver's Mi-Jung Lee