Moderna to be new 'workhorse' vaccine for B.C. as Pfizer supply dries up

No Pfizer vaccines arriving next week Canada's first major hurdle in its vaccine rollout is looking much more serious than first thought.

Vancouver — B.C.’s health minister says plans are underway to modify the province’s vaccination plans after the bombshell announcement from the federal government that the anticipated reduction in Pfizer vaccine supplies at the end of the month had evaporated completely, with booster shots and initial long-term care inoculations taking priority.

There will be no doses of the sub-zero vaccine coming into Canada next week, forcing the prime minister onto his back foot as provinces scramble to meet vaccination schedules for the second booster shot, which had already been expanded beyond Pfizer’s suggested 21-day interval between the first and second doses.

"To be precise it'll make 5,800 doses' worth of difference, which is very significant for us but something we hope we'll be able to deal with," said Health Minister Adrian Dix of the shortfall next week. “Hopefully this is a one-time interruption, but what we can do in British Columbia is use the vaccine we receive and use it effectively on vulnerable populations and that's what we're going to do -- and that means (the) second dose is particularly important.”

Up to now, more than twice as many doses of the Pfizer vaccine (94,575) have arrived in B.C. compared to Moderna’s (38,900), the only other vaccine currently available. The first doses of the Pfizer vaccine, which was approved and available first, have been administered to 73,393 British Columbians compared to just 18,976 for Moderna, but that will change.

"Moderna will ... certainly become our workhorse vaccine for first doses," explained Dix, emphasizing there’s been no interruption in supply from that company.

The supply interruption from Pfizer, which is scaling down production to increase long-term vaccine-making capacity, comes at a difficult time: on Wednesday, the first British Columbians who were vaccinated will begin getting their second, booster shot that provides maximum immunity to COVID-19. The pharmaceutical company had advised a three-week wait between shots, but the province’s top doctor did what many public health officials have done and expanded that by a couple weeks, for 35 days between shots.

While Dr. Bonnie Henry has faced criticism for pushing the timeline and not reserving doses for those second shots, she pointed out protection from the two vaccines was over 92 per cent after just one dose.

“What we're learning is that the short-term protection is achieved rapidly, and it's very high,” she told reporters last week, though she acknowledged more research is needed to see how long immunity lasts and how effective the booster shot is after a longer wait.

"Right now the recommendation is you can flexibly look at that interval for up to 42 days,” said Canada’s chief medical health officer, Dr. Theresa Tam on Tuesday. “(After one dose) there is reasonable vaccine effectiveness so it's a balance between the number of people being vaccinated for the first dose and following up with the second dose when you have a vaccine."

The federal government is responsible for procuring vaccine supplies, with the provinces responsible for administration. Federal officials insist they have assurances from Pfizer that they’ll make up the current shortfall and deliver all previously-committed doses before the end of March with 80 million doses expected in the country by the end of the year.