Here's how everyone in B.C. could get a vaccine shot by Canada Day

The B.C. government's vaccine page still says the rollout of first doses for all people in the province won't be finished until September.

But in the past week, a number of things have changed to quickly accelerate that timeline.

"I'm very very hopeful that come summer we will have met our objectives," said Premier John Horgan on Friday.

Horgan's comments came the same week Provincial Health Officer Dr. Bonnie Henry said everyone in the province could receive a first shot by early July, or even late June.

The B.C. government says an updated rollout plan to help people understand those claims is coming. In the meantime, here's a look at why those timelines are feasible — and what could happen to scuttle them.

How we get to 4 million

Three things happened this week to allow B.C.'s timeline for first doses to go from the end of September to the beginning of July.

The first was the decision to extend the maximum amount of time between giving the first and second dose of the Pfizer and Moderna vaccines from six weeks to four months.

The other two events took place on Friday: the approval by Health Canada of the Johnson & Johnson vaccine, and an additional 3.5 million doses of the Pfizer vaccine in the next three months.

What does all that mean?

There are around 3.8 million British Columbians who are eligible for the vaccine but have yet to receive a shot. Between March and the end of June, Canada has been promised approximately 30.5 million vaccine doses from Pfizer, Moderna, and AstraZeneca.

The federal government is distributing vaccines according to population, and approximately 13.22 per cent of the country lives in B.C. Do the math, and that adds up to just over four million doses coming to the province by the end of June.

That's enough to give a first dose to every adult in the province who can receive it, and complete the second dose for the approximately 200,000 who have only received one so far. And in theory, it would allow new supply from July onwards to be reserved for second doses.

What could go wrong?

It's an estimate, relying on companies providing the amount of vaccine promised to Canada at promised schedules.

And it's contingent on the B.C. government creating an operation that will have the capacity to vaccinate more than 50,000 people a day at its peak.

"In April … we'll have a lot more information on whether we're able to vaccinate the 10,000 to 20,000 a day first, and then scale it up rapidly to a much higher number. This is no mean feat," said Mahesh Nagarajan, a professor of operations and logistics at UBC's Sauder School of Business.

"Clarity on the hiring plan, the location plan, the processes that are going to happen, the call centre plan, the IT plan … those are the things we're waiting to see."

At the same time, the available supply doesn't factor in the amount that could be provided by Johnson & Johnson and AstraZeneca in the coming months, beyond the 500,000 or so doses of AstraZeneca provided this week. Those doses could accelerate the timeline further, or give contingencies in case there are delays to Pfizer or Moderna supplies.

They're all reasons why Health Minister Adrian Dix hasn't yet committed to a new target date, saying the government has been working on new timelines given the new information this week.

"We're hopeful that we could get everyone who wants their first dose by July, and maybe that time can move up now that we've seen more vaccines," Dix said.

And he cautioned that in the meantime, the province continues to see a rise in transmission.

"Things will get better in the summer, but right now people absolutely have to follow the rules."

CBC British Columbia is hosting a town hall on March 10 to put your COVID-19 vaccine questions to expert guests, including Provincial Health Officer Dr. Bonnie Henry. You can find the details at cbc.ca/ourshot. Have a question about the vaccine, or the rollout plan in B.C.? Email us: bcasks@cbc.ca