What to Do If You Test Positive for Covid-19 Antibodies - Bloomberg

What to Do If You Test Positive for Covid-19 Antibodies - Bloomberg

I Had to Take Five Antibody Tests to
Get Results I Could Believe

 After four
contradictory results, the author gets a reading she can trust. But what’s her
responsibility to people without immunity? And what happens if it doesn’t last?

By

July 7, 2020, 9:00 AM GMT+1

“Dear Stephanie,” the email said. “Your results are
complete. The test result is: Positive.”

After my fifth test for antibodies against the novel
coronavirus, the lingering doubts were finally gone: I had been infected
earlier this year. It’s the only time in my life I’ve been happy to be
diagnosed with a disease—albeit one I’ve already recovered from. And while I
first felt a sense of liberation and a lifting of anxiety, now I have new
reservations about how my new status allows me to behave.

Unlike swab tests that look for active cases of Covid-19,
antibody tests have the power to look into the past, seeking telltale proteins
in the blood that indicate whether a person has ever been exposed to a specific
pathogen. I couldn’t get a swab test when I fell ill in February, so I was
unsure if I had it. In May, I wrote about taking four different coronavirus
antibody tests that used finger-prick blood samples. Two were positive and two
were negative, leaving me confused. That story generated loads of email from
readers anxious about their own status, with many sending me their results to
ask what I thought (though I’m neither a doctor nor a scientist) and urging me
to take more tests. Some were incredulous—angry even—that they’d tested
negative.

My fifth test, made by global healthcare giant Abbott
Laboratories, used an intravenous blood draw sent to a lab, which many believe
produces a more accurate result than the finger-prick kits I’d used before.
Abbott says the test is 100% sensitive to SARS-CoV-2 antibodies, meaning it
won’t miss any past infection, and it’s 99.6% specific for patients if taken 14
days or more after symptoms started, so it has only a tiny chance of confusing
coronavirus antibodies with those of another pathogen.

So what does it mean to be positive? I’ll be honest: It has
given me some peace of mind. Antibodies against the coronavirus might protect
me against another infection, though there’s no guarantee. Having gone
stir-crazy working from home for the past three months, I’m even thinking about
venturing back to the office one day a week.

I’m not alone. As economies reopen and employers consider
ways of getting people back to work, some companies are looking at antibody
testing to nudge employees off their sofas and out of endless Zoom calls.
Others are using them to see if they have the right procedures in place to
prevent infection.

But the tests remain an imperfect tool. Even the most
reliable aren’t the “game changer” that U.K. Prime Minister Boris Johnson once
proclaimed, at least not yet. Doubts
remain about how long coronavirus antibodies last and how much protection they
actually afford. The virus simply hasn’t been around long enough for us to
have measured the duration of any natural immunity. A recent study in the U.K.
reported that Covid-19 antibodies remained stable in a majority of infected
people almost two months after they were diagnosed, but as many as 8.5% of
patients didn’t develop antibodies at all. After the first SARS pandemic in
2002-03, researchers found that patients maintained antibodies for an average
of two years, but it’s unclear if the same holds true for Covid-19.

That doesn’t mean antibody testing is useless. We need it to
help us understand how long antibodies last and what role they play, says Mary
Rodgers, head of Abbott’s global viral surveillance program. And knowing
whether a person’s illness was in fact Covid-19 might prove valuable in
diagnosing other health conditions in the future. “We’re seeing cardiovascular and lung effects, even in people who were
asymptomatic,” Rodgers says. “Until we understand who’s at risk for those
complications, we need to be keeping track of who actually had it.”

For me, testing positive has been a moral minefield.
Initially, I felt liberated, as if the gates to a super-elite Covid-positive
club had opened and I could finally go out. But when I really thought about it,
I realized I still need to be a good pandemic citizen. In the U.K., you are
required to wear a mask on public transport, which I rarely use these days. I
normally wear a mask when I enter a store, but when I recently darted into a
near-empty bookstore to quickly buy a novel for my daughter, I didn’t. I felt
guilty in retrospect. Although many people in London are not wearing masks
in stores, I’ve decided I will continue to do so, if only to avoid making
other shoppers nervous.

While it’s not a get-out-of-jail-free card, testing positive
has helped ease some fears. To celebrate, I invited two old friends over for
socially distanced drinks in my back garden. They hadn’t mixed with anyone
outside their house for months, and were comforted a bit by my test result.
Soon after, I even went to a long-delayed dentist appointment. I remain worried
about the rest of my family, who haven’t had symptoms or tested positive. But
it has made the idea of going to the office occasionally look less scary.

Companies organizing antibody testing for staff aren’t
treating it as a way to fill empty desks. Credit Suisse Group AG is offering a
test from Swiss drug giant Roche Holding AG to employees returning to offices
regularly in Switzerland and looking to roll it out to other hubs, but the bank
doesn’t get to see the results. It’s more for their peace of mind, a spokesman
says.

Other banks are holding off. Goldman Sachs Group Inc. hasn’t
decided whether to go ahead with antibody testing, a spokesman said. In the
U.K., JPMorgan Chase & Co. has so far decided against testing staff for
antibodies because of the uncertainty
around immunity to future infection.

The U.K. government ordered 10 million antibody tests from
Abbott and Roche to test health-care workers in England after validating their
accuracy, albeit in small samples. But many companies remain unsure whether
antibody testing for their staff is worthwhile, given the lack of government
guidance, says Jack Latus, managing director of Latus Health Ltd., an
occupational health provider that’s offering Covid-19 testing to employers such
as JP Morgan. Latus argues that continuous testing for antibodies is better
than nothing.

“If we keep testing people to see how long they have the
antibodies for, they should be safe to perform more customer-facing activities or
able to work across multiple sites,” Latus says. “You can start building your
business continuity plans. At the moment everyone is planning blind. If you
don’t know the status of your employees, you can’t plan.”

Public health authorities in several countries are testing
populations for antibodies to find out the prevalence of infection. A survey of
1,757 people in England found that 5.4% tested positive for antibodies,
excluding those reported in hospitals and nursing homes. The U.S. Centers for
Disease Control and Prevention said at the end of June that a national survey of
blood samples showed that for every confirmed case of Covid-19, there were 10
more people with antibodies. With 2.3 million confirmed cases of Covid-19 in
the U.S., that means the number of infected and asymptomatic people could be 23
million.

The reluctance of companies to check for antibodies might
stem from reports that many tests were unreliable, with some regulators failing
to police products being offered. In the U.S.,
the Food and Drug Administration allowed dozens of rapid finger-prick test
kits to flood the market in mid-March without reviewing whether or not they
worked. At the end of May, amid increasing reports questioning their accuracy,
the FDA banned more than two dozen tests from being sold. The agency has given emergency use approval to more than 20
antibody tests, including the one made by Abbott. Independent studies of
the Abbott test confirmed its accuracy.

“The finger-prick test often can’t detect low levels of
antibodies, so they’re more likely to miss people,” says Alexander Edwards, an
associate professor at the University of Reading who researches diagnostic
testing. “You get into this gray area with people with mild symptoms. And what
you want to use the antibody test for is all those people who didn’t get a swab
test.”

One company that’s embraced antibody testing is Whitecroft
Lighting Ltd., a commercial lighting manufacturer based in the north of England
that tested more than half of its 400 employees. Many staff continued working
during the lockdown, supplying lighting to some of the pop-up hospitals
dedicated to Covid-19 patients, and they were eager to find out their status.

Neil McCarroll, the company’s managing director, says they
debated for hours whether they should offer the tests, thinking it might even
make people more anxious if they found out that someone they worked next to had
antibodies from an infection they had not been aware of. Although the company
had no confirmed cases of Covid-19, about 8% or 9% of about 260 who were tested
came up positive for antibodies according to the Abbott test; the majority had
experienced no symptoms. Everyone who took a test shared their results with the
company, even though McCarroll told them testing wasn’t mandatory and they
could remain anonymous.

“It’s all about the anxiety,” he says. “People wanted to
talk about it. Opening their envelope was exciting. There was banter about it.
There were people who were upset they didn’t have antibodies, but we’ve had a
number of retests that confirmed they didn’t have it.”

McCarroll says testing has reassured management that the
company has the right social distancing and sanitation procedures in place to
prevent infection. While the meaning of testing positive remains unclear, the
desire to find out was overwhelming. “One hundred percent of staff said they
wanted to know,” he says. “I am not sure it changes anything for them, but they
just want to know.”

I, too, have concluded that knowing is better than not
knowing, even though I’m still following government guidelines on social
distancing and working from home—waiting for scientists to figure out what it
really means to test positive. And I might just get tested again in a few
months.