New Brunswick racing ahead of federal guidance on second boosters

New Brunswick Public Health is racing ahead of expert federal advice with its decision to expand eligibility for second COVID-19 boosters to people as young as 50.

The province announced the expansion of the second-booster program last Friday, despite the National Advisory Committee on Immunization taking a slower approach by recommending a second-booster campaign for people 80 and older.

And University of Ottawa epidemiologist Raywat Deonandan says the province is making the right call.

"Maybe they have done their analysis for their particular region and determined that a larger demographic is at greater risk that the national scope would suggest," he said.

"Scientifically, you would err on the side of pandemic caution by going faster." 

The federal committee said boosters in the general population may be needed by fall and doing anything before that could be sooner than necessary.

"Planning should take into account that vaccine deployment may be required for broader population groups in the fall of 2022 or earlier depending on the COVID-19 pandemic context," it said in its April 5 report.

Canada's chief public health officer, Theresa Tam, repeated that in a briefing Tuesday, saying three doses of vaccine are important and a fourth is important "for the highest risk."

Despite that, the province announced that second boosters will be available to people 50 and up starting next week, April 19.

Its news release said the decision was based on "released initial guidance from the National Advisory Committee on Immunization (NACI)."

It also cited "demographic, epidemiologic, chronic disease burden, and hospitalization data specific to New Brunswick," though the province isn't saying exactly what the data show.

Provinces can choose to move faster

Department of Health spokesperson Bruce Macfarlane said NACI's advice is only advice, and provinces can choose to move faster based on "their local risk assessment."

He said New Brunswick's aging population means it has a larger share of people over the age of 50 than many other provinces. And he said people over 50 make up 82 per cent of COVID  hospitalizations to date in the province.  People 50 to 59 years old account for 13 per cent of all hospitalizations, he said. 

"We expect the second booster for this age group will help to protect many New Brunswickers from severe illness and hospitalization," he said.

Nova Scotia and Prince Edward Island are sticking with people 70 and up for now, though Ontario is going with 60.

Deonandan says while people older than 80 have the highest benefit-to-risk ratio with another booster, the benefit still far outweighs the risk in other age groups. 

"NACI is being hyper-conservative in focusing on that age group," he said. "So the provinces I think are justified in lowering the age bracket based upon the same logical analysis."

New Brunswick is also deviating from NACI advice on the interval between booster doses.

The committee suggested provinces administer second booster doses six months after first booster doses.

But New Brunswick is bucking that advice with a five-month interval.

NACI said the six-month wait could be balanced with "local and current epidemiology."

Deonandan says NACI's proposed six-month interval is based on an individual's optimal immune response but doesn't take into account how much community transmission of the coronavirus is happening. 

A six-month gap will give someone the maximum protection but that timing may not coincide with the projected peak of the current sixth wave in early May, he said. 

"If you're waiting for an optimal personal immune reaction, that may take you past that May peak," he said.

"It makes more sense to get your dose as soon as you can so you have optimal immunity when the threat is at its most dire."

NACI said in its April 5 report that while a second booster of an mRNA vaccine is just as safe as earlier doses and will provide more protection than a single booster, "the duration of protection is currently unknown." 

A study in Israel earlier this year found that fourth-dose protection from infection was "short-lived," though protection against severe illness appeared to remain strong. 

Last week, in response to a group of pediatricians recommending that mask mandates be reinstated in schools, Chief Medical Officer of Health Dr. Jennifer Russell said it was "more important to get vaccinated than it is to wear a mask."

Deonandan says while it appears there's "some conflict" between the province's push for second boosters and its reluctance to bring back mask mandates, it actually makes some sense.

If the province is downloading decision-making responsibility to individuals for their own behaviour, including masks, it still has a broader role to play in pushing for population-level immunity, he says.

The epidemiologist says he's relatively optimistic about how the pandemic will evolve heading into this summer.

He expects the sixth wave to be tough, with a case peak exceeding the winter Omicron wave, but more boosters and antiviral drugs could mean a less severe impact on the health care system.

And if the worst is over by June and provinces keep promoting boosters through the summer, "then we're in a good place to be in the fall to prevent any kind of wave, frankly," unless a new variant appears.