A small study from China that followed 37 positive but asymptomatic people just produced some disappointing results.

Antibody levels against COVID-19 were far lower and even nonexistent in asymptomatic individuals compared to those who had obvious symptoms of the virus. As well, antibody levels fell more quickly in those who never showed symptoms.

A University of Toronto professor told CBC that it would appear from this small study published in Nature that a past COVID infection may not confer lasting immunity. That means that herd immunity isn’t something we can count on to protect the majority of populations that haven’t been infected. It also means those who’ve already had COVID could theoretically get sick again if their immune system lacks a memory.

Studies like this one mean that serological blood testing – also known as antibody testing, may have limited clinical value. Alberta has become the first province to announce a program for antibody testing. In B.C., the main point person on antibody research and testing is Dr. Mel Krajden, medical director of the BCCDC Public Health Laboratory. I spoke with him at length; here’s a condensed, edited version of our conversation.

Where are we, at this point in time, with antibody testing? Everyone is anxious to know if it will be useful for determining the prevalence of COVID-19 in our communities.

We’re part of the national team working on this. We’ve been trying, in a nutshell, to test and validate a bunch of commercial assays. Many are performing reasonably well, with high specificity and sensitivity. Some people don’t make antibodies at all, or less if they have had mild infections.

There’s a lot of emotion when it comes to immunity since people want to think they have protection (against reinfection) once they’ve had COVID but no one yet knows the durability of protection. (Medical experts) are fearful about this notion of immunity passports because what we don’t want is people no longer physically distancing or having a false sense of security. This is a challenge from a public health perspective. You don’t want to mislead the public about the potential for antibody testing.

Serology tests should be seen as just like a little blanket you go to bed with; it’s not that protective.

So what is the main goal for antibody testing?

Serology is important to determine seroprevalence in communities. Quebec and Ontario will have a higher prevalence in dense cities like Montreal and Toronto. It’s useful to know if someone who is seropositive actually has some degree of protection. With other coronaviruses, antibodies hang around for some time but no one knows for sure with COVID.

So really, it has limited value. It can tell you the proportion of the population that got infected, that’s the value. It can also identify people who are sero-protected and then we can study them longitudinally. I would caution people using it for emotional use. Some people don’t make antibodies but for those with them, it shouldn’t be seen as an opportunity to say ‘I’m home free. I’m protected and I don’t have to worry about getting it.’

I’ve heard of some Canadians who’ve been paying for antibody testing (blood samples are sent to private labs in California and elsewhere.) I imagine companies like LifeLabs may want to offer it to private companies. What are the harms?

I would say no one should think they are home free. The messaging that goes with the lab results should be honest about the limitations. It should come with caveats.

Is it a wise investment for companies or the general public?

I don’t think it’s crucial. But for governments, it’s worthwhile to know what proportion of the public has been infected. We are looking at this now among health care workers. (Previously, Krajden said that such information about immunity and antibody levels could be reassuring to health care workers).

Have you chosen the test or tests you will use in B.C?

We’re still figuring out what test is best so we can land on the most responsible solution. We’re evaluating about a handful, including ones from Siemans, Roche, Abbott and Ortho.

We’ve done some testing on health care workers and some other groups who volunteered for this kind of research months ago and now we want to make sure we trust it.

We worked with public health, sought volunteers like health care workers in long term care facilities. We know the time frame they were diagnosed and now we are able to see the behavior of the test over time.

I wrote an article about how 25% of health care workers had been infected with COVID up to June 8 which seems really high and I guess it’s even higher now. There were 662 when I wrote the story.

Well the challenge with health care workers is that they are all more likely to be tested because we need to know if they should not go to work and the value of personal protective equipment, etc. Numerically, the number you cite is correct but the true proportion who got infected at work, or traveling on transit or in their homes and community settings, we don’t know.

We oversampled health care workers. I guess my feeling is that PPE works so as long as it’s used and used responsibly. I don’t think the risk to average health care workers is incredibly great. I don’t think they are tremendously or disproportionately at risk.

So how and when will antibody testing be rolled out?

At first, it will be directed to seroprevalence, then we may use it for some diagnostic dilemmas. We have to try to get Canadian consensus on the best uses of it. I would bet we’ll be rolling out a program within a month but it will involve very specific populations since, at this point, serology is not for prime time use.

We know safe and effective vaccines are our best hope. Dr. Anthony Fauci has said that he thinks vaccines may only provide protection for months which means we might have to get vaccinated a few times a year.

Yeah, I mean nobody knows that at this point. I think he’s thinking out loud. I like Fauci, he does a great job, but no one has a crystal ball.

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Dr. Patty Daly and Dr. Eric Grafstein have been leaders in B.C. healthcare for a few decades now. The married physicians are intrepid leaders and during the COVID-19 pandemic, they’ve piloted their colleagues gallantly.

Daly is the Vice President, Public Health, and Chief Medical Health Officer for Vancouver Coastal Health. Grafstein is the regional head of emergency medicine for Vancouver Coastal Health and Providence Health Care. There have been 899 cases of COVID-19 in the Vancouver Coastal Health region (population 1.5 million) and 2,550 across the whole province.

They’re members of the reform synagogue called Temple Sholom in Vancouver so when Rabbi Dan Moskovitz convened a webinar for congregants and the community at large, he naturally tapped them.

I’ve watched the session that took place earlier this month and it was surprisingly reassuring in tone. Grafstein and Daly are about as well suited for a pandemic as anyone since they embody logic and calmness under pressure.

Grafstein debunks the need to wear gloves at all times (they may give a false sense of confidence; handwashing and sanitizer are the best modes of hygiene). He’s meticulous but not obsessively so. I watched a video of CNN’s Dr. Sanjay Gupta wiping down every product in his grocery bag; Grafstein said he doesn’t clean packages of products he buys at the grocery store but he does wash produce before it’s used and he cleans his hands incessantly.

Referring to the resumption of activities like canceled or delayed surgeries, Daly said:

“We’ve significantly bent the curve, so we can begin to lift some public health measures.” She also spoke about children who have a much lower risk of infection for inexplicable reasons, and that’s why daycares and day camps can likely re-open this summer, with some restrictions. Thousands of children have been tested for COVID-19 in B.C. and less than one percent have been confirmed to have had COVID-19.

Daly spoke to the anxieties people have about even going outside.

“It’s quite safe to be in parks, exercising outdoors. I’m not aware of any transmissions through casual exposures outdoors. People can be reassured that there isn’t a risk when someone passes them on the street.  We shouldn’t fear that passersby will infect us as long as they aren’t coughing or spitting directly in our faces.”

Asked by Rabbi Moskovitz about COVID-19 transmission to doctors, Grafstein said he knows of only one medical colleague at St. Paul’s who got the virus and he is “positive he didn’t get it in the hospital.” (Nearly a quarter of COVID-19 cases have been among health care workers, mostly those who work in long term care facilities).

But Grafstein acknowledged that the shortage of personal protective equipment for healthcare professionals and workers has been an ongoing issue requiring “shepherding logistics and procurement.

“At various times there’s been a concern on whether we’d run out. I wear a mask and a face shield but I keep it on throughout my shift.”

Daly said every positive case is followed up and “Eric is right, this is different than SARS, almost every health care worker transmission has occurred in the community,” she said, noting the community-acquired cases are what led to outbreaks in long term care facilities.

Not surprisingly, the rabbi asked about when houses of worship might be allowed to reopen. Daly said she can’t predict when that might happen:

“Gatherings over 50 will be the last thing we lift. Houses of worship have to protect older people…” she said.

In the fall, she expects university classes might be a combination of virtual and in-class teaching.

Asked at the end of the hour-long sessions about any blessings or silver linings that have come from the pandemic, Grafstein said the uptake of virtual health care technology is one. Apart from the utilization of technology, he cited the fact that the pandemic has led to “people coming together to sort out problems, to tackle it, and that gives me great confidence.

“Canada has done better (than many other nations),” he said, before giving a shout-out to his wife and other public health officials.

Daly echoed her husband’s comments about the use of technology.

“Like in any war, there is innovation,” she said, adding that governments have “come together to do the right thing.”

Rabbi Moskovitz got the last word in, praising the two for being the kind of “heroes we clang and bang pots for, and who we pray for.”

Watch the session on Youtube here.

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