In an email to Global News, PHAC said the country’s surveillance data “continues to indicate low rates of COVID-19 cases following vaccination.”
The agency added, though, that only nine jurisdictions in Canada are currently reporting on “vaccine history questions” that contribute to the country’s COVID-19 dataset.
PHAC said as of May 13, 2021, a total of 13,461 COVID-19 infections were reported in those who had received their first vaccine dose.
The agency said 64 per cent (8,565) of the cases were reported in individuals who were still within 14 days of their first vaccine dose.
Meanwhile, 36 per cent — or 4,896 infections — were reported at a minimum of 14 days after the person’s first dose was administered. The agency said this reflects the “time period required to build partial immunity” to the virus.
PHAC said the 4,896 cases reflect 2.3 per cent of cases reported from the nine reporting jurisdictions since the rollout of vaccines began.
The agency said out of the 4,896 cases for which additional information was available, 9.2 per cent of the infections resulted in hospitalization, and three per cent ended in death.
PHAC noted, though, that because Canada’s vaccine rollout has focussed primarily on older adults, the cases reported after vaccination “tend to be from an older demographic.”
PHAC added that because of this, “comparisons should not be made between hospitalizations/deaths among cases following vaccination and hospitalizations/deaths among all Canadian COVID-19 cases.”
Dr. Zain Chagla, an infectious disease expert with McMaster University, said these numbers are “pretty remarkable.”
“This is good,” Chagla said. “You’re looking at numbers in that 95 per cent plus ballpark in terms of preventing infections.“
Chagla said while some people may look at nearly 4,900 cases after the first dose and think “that’s terrible”…
“But in the grand context, during the same time period, you’re looking at 500,000 plus cases of COVID-19 outside of children, and only around 5,000 of them represented among the group that’s had a first dose of vaccine that’s 14 days out,” he said, adding that it is “quite encouraging.”
Between when the first dose of a vaccine was administered in Canada in mid-December and the end of April — around two weeks before May 13 — 750,569 COVID-19 cases were reported.
In the same time period, a total of 1,3420,198 doses of the approved COVID-19 vaccines were administered.
After 2 doses
What’s more, the number of novel coronavirus infections after vaccination dropped even further among those who had received two doses.
By May 13, 3.54 per cent of Canada’s population was fully vaccinated against COVID-19.
The PHAC data showed that as of May 13, 2021, a total of 740 COVID-19 infections were reported in those who had received both vaccine doses.
The agency said 21 per cent, or 153 of these cases were reported within seven days of the individual’s second dose.
Seventy-nine per cent — or 587 cases — were reported at a minimum of seven days after the individual had received their second shot, which the agency said reflects the “time period required to build full immunity after two doses.”
“The 587 cases with full immunity reported reflect 0.3 per cent of cases reported from the nine reporting jurisdictions since vaccine rollout started,” PHAC said.
The agency said of these cases for which additional information was available, 5.5 per cent resulted in hospitalization and 3.5 per cent ended in death.
Asked why Canada is still seeing infections post-vaccination, Chagla said it’s not “unreasonable to have some breakthrough cases.”
“None of these vaccines (offer) 100 per cent protection against symptomatic COVID-19,” he said. “And so we’d expect breakthrough cases.”
Chagla said, ultimately, that’s not the point of the vaccine campaign.
“It’s that (COVID-19) becomes a manageable outpatient disease, that people aren’t being hospitalized in droves,” he said.
He said what this data does is help to give a “ballpark sense” of what is happening in the country among those who have been vaccinated.
He said it shows that breakthrough cases are happening, but “they’re much, much less likely than getting infected without a vaccine.”
U.S. sees small amount of breakthrough cases
On Tuesday the U.S. Centers for Disease Control (CDC) published a report documenting what it called “breakthrough” cases in those who had been fully vaccinated against COVID-19.
The CDC examined cases between Jan. 1, 2021, and April 30, 2021, and found around 0.01 per cent of people contracted the virus after full vaccination.
The study said a total of 10,262 vaccine breakthrough infections had been reported as of April 30.
Meanwhile, the CDC said as of April 30, approximately 101 million people had been fully vaccinated.
The centre said, “even though FDA-authorized vaccines are highly effective, breakthrough cases are expected, especially before population immunity reaches sufficient levels to further decrease transmission.”
The CDC added, though, that vaccine breakthrough cases infections occur in, “only a small fraction of all vaccinated persons and account for a small percentage of all COVID-19 cases.”
How many vaccines have been administered in Canada?
As of Wednesday evening, 21,886,005 COVID-19 vaccines have been administered across Canada.
That means, so far, 53.13 per cent of Canadians have received at least one dose, according to Vaccine Tracker Canada.
Further, a total of 1,743,718 people in Canada are now fully vaccinated, meaning they have received two doses of a COVID-19 shot.