Vancouver Coastal Heath is warning that there is an "increased chance of further unidentified exposures" to measles.
This came as the regional health authority announced two more confirmed cases in the Lower Mainland.
It brings the total of confirmed cases to 10 in the current outbreak.
One of the new cases is linked to a previous known person with the measles.
The source of the other case is still being investigated.
Vancouver Coastal Health has released a list of venues (with times) where people may have been exposed to the virus.
Measles is a highly infectious, airborne disease that's associated with a rash on the face and chest.
"People born before January 1, 1970 and those who have had measles are likely immune. Those born between 1970 and 1994, or grew up outside of B.C., may have had only one dose of measles vaccine and need a second dose to be fully protected," Vancouver Coastal Health states on its website. "Those born after 1970 who are not fully immunized with two doses of a measles vaccine, and who have not had measles disease in the past, should receive a dose of measles mumps, rubella (MMR) vaccine."