Public health officials are asking eastern Fraser Valley residents to remain vigilant against measles symptoms, after as many as 60 women and their newborn babies were exposed to the virus at an Abbotsford hospital last week.

"We're continuing to see cases. We had a positive blood test in a three-year-old child yesterday, so some of it appears to be stretching into the community itself," said Dr. Paul Van Buynder, chief medical health officer for Fraser Health.

Fraser Health issued a public warning on Aug. 8 after someone infected with measles visited the post-natal unit at the Abbotsford Regional Hospital and Cancer Centre.

Relatively low immunization rates in the communities of Abbotsford, Mission, Chilliwack, Agassiz, Harrison Hot Springs and Hope have led to several clusters of the virus in previous years — the most recent in April 2010 shortly after the Olympic Games.

Putting others at risk

Dr. Arthur Caplan, the director of medical ethics at the New York University Langone Medical Center, told CBC News these warnings are a reminder that vaccinations are a moral responsibility to vaccinate.

"You're not only putting your own child at risk or yourself at risk if you don't vaccinate, but you put others at risk," he said. "Vaccination works best when everybody does it."

The most effective protection against the virus is two doses of the vaccine, which is free to all those born after 1957.

Residents in Fraser East are encouraged to contact their doctor to receive the vaccination.