VANCOUVER -- Health officials are urging people not to line up outside COVID-19 vaccination clinics in the hopes of scoring a leftover dose at the end of the night.

Provincial health officer Dr. Bonnie Henry was asked about vaccine-seekers during her pandemic briefing on Thursday, and stressed that people should be waiting for their scheduled appointment.

"Don't line up unless you have been asked to come," Henry said. "There is a plan with every clinic for every dose."

Henry's remarks follow days after a school teacher from B.C.'s Lower Mainland tweeted a photo showing colleagues lined up outside a Surrey clinic hoping for a dose of vaccine.

Surrey teachers are getting vaccinated early due to the city's consistently high COVID-19 case numbers, while teachers in neighbouring municipalities are stuck waiting for the province's frontline worker immunization program to resume.

Sheelagh Brothers told CTV News she knows some teachers outside of Surrey have managed to get vaccinated by waiting outside clinics, prompting others to rush out in a frenzy when they get word that a location is handing out extra doses. That's what happened on Tuesday night, she said.

"We all dropped everything and jumped in our cars," Brothers said.

Vaccine has to be used within hours of being diluted – but Henry stressed Thursday that every dose that's prepared has an intended use.

"There's people who are on standby to come in and be booked in if there's no-shows," she said. "The plans often involve things like taking any end-of-day doses to the emergency department, to the hospital, to a local place where we know that there's a need."

B.C. teachers are among the groups that were promised early vaccination using doses of AstraZeneca, but that program has been paused while officials await updated guidance. AstraZeneca is currently only going to people age 55 and up due to very rare reports of blood clotting associated with the vaccine in other parts of the world.

On Wednesday, B.C. Education Minister Jennifer Whiteside said she can appreciate why teachers are anxious for vaccine protection, but insisted schools are safe. She pointed to B.C.'s newly expanded rules for mandatory masks in grades 4 through 12 as one way risks are being minimized.

Brothers told CTV News the mask mandate is helping but that many teachers are still nervous about being exposed to COVID-19.

"We're so tired of worrying every time someone coughs or sneezes or their masks fall below their nose," she said.

With files from CTV News Vancouver's Bhinder Sajan