The measles outbreak that started in a religious elementary school in the Fraser Valley has spread into the general population, health officials confirmed Thursday.

The Fraser Health Authority is reporting new apparent measles infections in Chilliwack and Agassiz, areas that typically have low immunization rates.

The virus is potentially fatal and at least one child has been hospitalized so far.

The first two confirmed measles cases involved students from Mount Cheam Christian School, where Fraser Health has said up to 100 other children could be infected.

The school community, which is linked to the Reformed Congregations in North America, is believed to have a vaccination rate of nearly zero.

Fraser Health is urging valley residents, especially older adults and children, to get both doses of measles vaccine, which it describes as the best possible protection from infection.

About one-third of children under five years old who contract measles end up in hospital.

The vaccine is being distributed to pharmacies and general practitioners in the Fraser Valley East region, including Abbotsford, Mission, Chilliwack, Agassiz, Harrison Hot Springs and Hope.

People with measles symptoms are advised to isolate themselves at home. If they are seriously ill and need medical attention, they are urged to contact doctors or hospitals to warn of their arrival.

The highly-contagious measles 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.

For more information on measles, visit the Fraser Health website.