A private blood-testing company's claim that the COVID-19 "pandemic is over" in a northern Alberta community could lull residents into a false sense of security, says an infectious diseases expert.
More than 1,200 people in the hamlet of La Crete, 700 kilometres northwest of Edmonton, paid $100 each in mid-December to have their blood tested for antibodies by Ichor Blood Services, a private lab specimen collection company based in Calgary.
The tests found antibodies in most of the 991 unvaccinated individuals who were tested.
Ichor CEO Mike Kuzimickas said he believes the results show La Crete is relatively safe from COVID-19.
"The pandemic is over in La Crete; they have reached herd immunity," Kuzimickas told CBC News in an email last month.
"We had 89 per cent of the unvaccinated population up there test positive for the SARS-CoV-2 spike protein antibody, which would indicate that they've seen the virus, they've developed some level of cellular immunity, and they're kind of good to go," he said in a follow-up interview from Mexico, where he is spending the winter with his family.
"They've developed underlying T-cell memory and they don't have to worry about it."
Kuzimickas is a mechanical engineer without training or expertise in epidemiology, virology or vaccines. He said he is interpreting the data the best he can.
Does prior infection provide immunity?
Experts say it isn't clear that immunity acquired from previous COVID-19 infection protects people against re-infection, especially with the new Omicron variant.
"If you roughly consider post-infection immunity as being kind of like a single dose of vaccine, these people [in La Crete] are still vulnerable to infection and they still could be vulnerable to severe outcomes as well," said Dr. Lynora Saxinger, an infectious diseases specialist at the University of Alberta.
Earlier in the pandemic, reinfection seemed rare, Saxinger said. But she said it is now clear that it is common, especially with the Omicron variant, which is much more infectious and seems to be better at evading vaccines.
"Infection alone is not as good protection as two doses of vaccine at the best of times," she said. "And certainly now it looks like three doses of vaccine are really required for good protection against this variant. So I don't think this is really relevant anymore."
Antibody level for COVID-19 immunity unknown
The hamlet of La Crete is part of a northwest health region that includes about 25,000 people. It has the lowest immunization rate in Alberta, with just 35 per cent of its eligible population immunized with two doses.
The expansive region is home to many diverse communities, but La Crete has made headlines during the pandemic for its resistance to observing public health measures. La Crete's population is about 3,500, with 8,000 more in the surrounding area.
Ichor Blood Services was engaged to do testing by the La Crete Chamber of Commerce. The company used a semi-quantitative spike protein antibody test developed by the Rochester, Minn.-based Mayo Clinic.
The voluntary testing was advertised by the chamber. Residents were asked to sign up and bring payment of $100 cash to their appointments, according to the chamber's social media posts.
Kuzimickas shared the results of the testing with CBC.
Of 1,219 tests completed, 991 people said they were unvaccinated, 203 declined to disclose their vaccination status and 19 said they had been vaccinated. Six people said they had been vaccinated and also infected with the virus.
Kuzimickas said the test measures antibodies on a scale from zero to 250 units per millilitre. He said that while levels can be higher than 250, his understanding is that once a result is over 250, the difference in protection is negligible.
Among the 991 people who were unvaccinated, the tests showed 36 per cent had antibody levels of 250 or higher, 53 per cent had levels up to 250, and 11 per cent had no antibodies.
Antibody levels of 250 or better were found in 28 per cent of the 203 people who didn't disclose their status.
The results showed that 95 per cent of the 19 vaccinated people had antibody levels of 250 or higher.
The 250-or-better result was also found in five of the six people (83 per cent) who had been both infected and vaccinated.
In an emailed statement, a Mayo Clinic spokesperson confirmed that like all commercially available tests, theirs is used to determine whether or not a person has developed an antibody response to COVID-19.
"There is no official 'immunity threshold' that has been established or officially endorsed to indicate that an individual is 'immune' to re-infection or disease," Suzanne Ferguson said in an email.
Discussing the test results, Kuzimickas said his lab has not determined what level of antibodies make a person immune to COVID-19 infection.
Saxinger said it's unclear what can be learned from the results provided by Ichor Blood Services.
She said most antibody tests used in research she has reviewed have been quantitative tests where a lot of work has been done to determine what level of antibodies would create immunity. But with Omicron, that level is changing, she said.
"I really don't think this shows what it sounds like they're saying it shows," Saxinger said of Ichor's test results.
She said recent evidence from the United Kingdom shows that protection from infection by a prior infection was just 20 per cent.
Saxinger said because the testing was voluntary and paid for by participants, it draws into question any conclusions that can be drawn about the broader community's population.
When asked what he told people in La Crete about the results, Kuzimickas said he just shared the results and told the community that in Ichor's opinion it was good news.
"That's great, you're not nearly in as vulnerable position as you thought. And we left it there. We're not providing medical advice. We're not telling them to disobey public health guidance," he said.
Kuzimickas said he believes the results show that the unvaccinated population in the area largely has some level of immunity.
Most unvaccinated Albertans have no immunity
Albertans don't generally have access to serology testing for COVID-19 antibodies through their physicians.
However, the province is using serology testing to assess how many Albertans have been exposed to COVID-19, said Grady Semmens, a spokesperson for Alberta Precision Laboratories.
In some cases, data is used to inform medical treatment decisions, but the test must be ordered by a physician and approved by provincial virology experts.
"At this time, there is a lack of evidence on whether having antibodies to COVID-19 means you are protected against reinfection with COVID-19 and if so, how long that protection would last," Semmens said in an email.
"This is especially true with newer strains of the virus such as the Omicron variant."
Immunized people are less likely to be seriously ill or be hospitalized than those who are unvaccinated, and Kuzimickas's belief about the unvaccinated population in the La Crete area having immunity doesn't align with the province's own serology testing.
During its last regular survey of blood samples in early October, Alberta Health found that about 40 per cent of those who were not vaccinated had detectable antibodies, which means the majority of unimmunized Albertans had no evidence of an immune response from past infection, spokesperson Christa Jubinville said in an email.
"The spread of the Omicron variant is putting our health-care system at risk, and we need to both maximize vaccine coverage and follow public health measures to protect our communities," Jubinville said.
She said infection plus vaccination provides much better protection than infection alone.
"With Omicron, there is an increased risk of re-infection in those who have previously had COVID, meaning it is even more important to be vaccinated, including after infection."
Still, Kuzimickas thinks it's time for provincial officials to rethink public health restrictions and to factor immunity through infection into requirements for proof of immunization.
"It's been two years. There needs to be a different approach to how to get out of this pandemic because what we're doing is a repeating cycle that's not working," he said.
Kuzimickas said that in the wake of the La Crete chamber sharing test results, half a dozen other municipalities have reached out to Ichor about group testing.
Saxinger recommends caution for any community considering setting up serology testing for COVID-19 antibodies.
"I don't think they should be spending money on that until they get an idea of what those numbers actually mean," she said. "I think it might actually create a false sense of security, which may not be the best idea right now."