B.C. not changing advice on second doses despite NACI guidance to use Pfizer, Moderna

All vaccine combinations are safe and effective, says provincial health officer Dr. Bonnie Henry

B.C.’s top doctor says the province is not changing its second-shot COVID vaccination advice, despite a recommendation from a national advisory body that those who received the AstraZeneca vaccine for a first dose get Pfizer or Moderna as a booster for a better immune response.

“Our advice has not changed,” provincial health officer Dr. Bonnie Henry said Thursday. “You make the choice that is right for you, because all the vaccines that we have here in use in B.C. are safe and highly effective.”

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The National Committee on Immunization is recommending that provinces stop administering the AstraZeneca vaccine in most cases, even as a booster shot for those who received it as a first dose.

On June 1, NACI said AstraZeneca recipients could get Pfizer or Moderna for their second shot if they wanted, but on Thursday, the body said an mRNA vaccine was the preferred choice. As well, NACI now says everyone should be given the mRNA vaccine first, unless they are allergic to them.

NACI vice-chair Dr. Shelley Deeks said the advice is based on the growing supply of Pfizer and Moderna, and the risk of vaccine-induced blood clots associated with AstraZeneca. But she said those who received one or two doses of AstraZeneca are still well protected, particularly against serious illness. “There is no need for a third dose at this time.”

The updated guidance on mixing and matching vaccines is based on research on immune-system response that showed people who had an mRNA vaccine such as Pfizer or Moderna after a dose of AstraZeneca had good or better immunity afterwards, said Henry.

Dr. Theresa Tam, the chief public health officer of Canada, said the new evidence in favour of mixing different types of vaccines included four studies in Germany. Researchers from Germany’s Saarland University published early data Wednesday saying giving Pfizer as the second dose after AstraZeneca, or two doses of Pfizer only, generated far more antibodies and T cells than two doses of AstraZeneca.

But Henry said the study was small and it’s too soon to know whether “that little bit of extra antibody” translates into better protection in the real world.

B.C. health officials are keeping an eye on additional studies, Henry said, “but I think we can be very reassured that two doses of whatever vaccines are safe and effective.” Other studies are looking at if a third booster will be needed for different strains.

In B.C., more than 300,000 doses of AstraZeneca have been administered, mostly through pharmacies, including 63,000 second doses, said Health Minister Adrian Dix.

Of those who received AstraZeneca, three people in B.C. experienced VIIT, a rare vaccine-induced blood clot.

Henry said fewer than half the expected doses of Pfizer will arrive in each of the first two weeks of July, while unprecedented amounts of Moderna are scheduled to be delivered through the end of June.

While about 325,000 doses a week of Pfizer will be shipped this week, next week and the week after, that will dip to 121,000 on July 5, from an expected shipment of 308,000. A similar dip is expected in the second week of July, but it’s not expected to slow down vaccination timelines for second doses, Henry said, adding Pfizer will make up the shortfall in the latter months of July.

Meanwhile, 962,000 doses of Moderna are expected over the next two weeks, more than has arrived since January.

Fourteen million doses of Pfizer-BioNTech and Moderna are being delivered in Canada this week and next, including a donation of one million doses of Moderna from the United States that was expected to arrive Thursday night.

Those booking second doses through the province’s mass clinics aren’t given a choice between the mRNA vaccine they receive — Pfizer or Moderna. Henry said call centre agents don’t know what clinics have what product — though most try to have both Moderna and Pfizer available — but she stressed the two mRNA vaccines are interchangeable.

The province reported 120 new cases of COVID on Thursday, including five in Island Health.

There was one COVID-related death reported on Thursday — an unvaccinated person in their 80s who was present during an earlier outbreak declared over at Richmond Hospital weeks ago — bringing total deaths to 1,739.

There are three outbreaks in long-term care or assisted living in the province, none of which are on the Island.

As of Thursday, 76.5 per cent of adults have received a first dose of COVID vaccine and 4.2 million doses have been administered, 768,008 of which were second doses.

For those not yet vaccinated, Henry said the reason may have less to do with hesitancy than complacency, “and we need to combat that by bringing vaccine to people and making it easy for them to get it.”

A lower vaccination uptake of first doses in Lake Cowichan has prompted Island Health to hold a multi-day clinic at the Cowichan Lake Sports Arena, starting June 23. Registering on the provincial website is advised but not required for first doses at the sports arena. A booking is required for second doses.


> To register for a vaccine, go to GetVaccinated.gov.bc.ca or call 1-833-838-2323

— With files from The Canadian Press

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