B.C. considering mixing and matching vaccines

By Shannon Waters April 29, 2021

Despite a decrease in expected Moderna shipments, the Ministry of Health says it expects to deliver second shots of the vaccine on time as health-care workers immunized in January and early February approach the end of their four-month vaccine interval.

B.C. should receive more Moderna doses in the second quarter of 2020 than the approximately 40,000 doses that arrived in the first, per the ministry.

However, if there are further disruptions to Moderna deliveries, B.C. will not delay second shots. Instead, the province “could consider using” Pfizer — the other mRNA vaccine that is currently more plentiful — for the second dose.

Delivery delays in late January prompted B.C. to extend the interval between second doses of Moderna from the recommended 28 days to 42. Then, at the beginning of March, the province preempted the National Advisory Council on Immunization (NACI) when it switched to a four-month interval for all second vaccinations.

The policy took effect immediately, leaving many health-care workers to learn their Covid booster shot appointments were cancelled when they showed up to them.

Michael Sandler, executive director of Nurses and Nurse Practitioners of B.C., told BC Today the decision to administer as many first doses as quickly as possible was always a bit risky.

“I think everybody was aware that that strategy could pose problems if there was a vaccine delay, if there’s a delivery delay with the shipment,” he said.

The latest Moderna delivery disruption slashed scheduled shipments to Canada by half this month. B.C. expects to get 82,300 Moderna doses by May 2, down from the 156,600 doses that were expected this week.

The province is still administering Moderna shots to British Columbians eligible based on their age. As of April 27, B.C. administered 322,808 doses of Moderna in total, including 18,056 second doses.

‘We need some more runway,’ nurses’ association says
Sandler said the ministry should be upfront with health-care workers about the Moderna supply situation sooner rather than later “so that people can start aligning the risk that they’re taking with the fact that they are still lined up for that second dose.”

“We recognize that the Moderna issue is outside their circle of influence, and it’s not ideal to do a mix and match,” he said. “But if they’re going to go down that road, we need early communication to that effect.”

The BC Care Providers Association told BC Today it could not comment on the possibility of mixing mRNA vaccines because it had “not heard from [the] Ministry of Health on this topic.”

The BC Nurses’ Union also declined to comment but did confirm to BC Today that the provincial health officer has raised the possibility of needing to mix doses of mRNA vaccines due to potential supply issues.

Not much to go on as ‘the science is evolving’
While there are trials underway to explore the efficacy and risks associated with mixing vaccines, Sandler cited “a paucity of studies” to inform B.C.’s public health officials.

“I’m feeling for the ministry in this scenario — there’s no good evidence and forms for practice for them to lean on, and nobody wants to be the first down that road,” he said.

Health authorities in the United Kingdom and United States have advised against mixing Covid shots, except in exceptional circumstances. Health Canada is still considering the data available on vaccine mixing, and NACI recommends that dual Covid vaccinations “be completed with the same COVID-19 vaccine product” if possible.

“Currently, no data exist on the interchangeability of COVID-19 vaccines,” per the committee.

Meanwhile, Quebec has announced it will mix mRNA vaccines as needed.

Whether B.C. goes down that same road or not, Sandler urged the province to keep health-care workers in the loop.

“You have to continue to consult nurses in this process,” he said. “Engage with the nursing workforce. Keep us informed.”