By her own account, Vancouver resident Shilan Garousi is a medical mystery, one that a local virologist says needs to be solved to better understand the long-term threat COVID-19 poses to us all.

Garousi, 36, says she came down with COVID-19 — twice.

She first fell ill with COVID-19 on March 7, 10 days before B.C.'s public health officer declared a health emergency to try to stem the pandemic.

She says after some early confusion, she was diagnosed with the disease, went through the accepted 10-day recovery period, and resumed regular life, only to have the symptoms come roaring back.

"To be honest, it's a medical mystery to all, and to myself I am as puzzled," said Garousi. "I do not have an answer."

Whether a once-infected patient can be hit with COVID-19 again after they appear to recover is an important question around the world and a key unknown, as countries hope that infected populations may have some immunity to stave off resurgences of the pandemic.

'One of the more complicated cases'

Garousi's case has grabbed the attention of Dr. Brian Conway, who echoes her words.

"It's puzzling.... One of the more complicated cases I've heard of," said Conway, medical director of the Vancouver Infectious Diseases Centre.

The big unknown: did Garousi never fully recover, and the second bout was a relapse of her first infection? Or did she beat COVID-19 and get infected again?

Conway says both are a possibility, since so much is still unknown about how the virus works and whether recovered patients have sufficient antibodies to give them some immunity.

South Korea, hit early with the coronavirus, has reported numerous recurrences in patients thought to have recovered from COVID-19.

Employees sit behind protective screens as part of preventative measures against COVID-19 in a cafeteria in Seoul. South Korea has reported numerous cases where patients who seemed recovered from the coronavirus test positive again. (Ed Jones/AFP/Getty Images)

On April 22, B.C.'s provincial health officer said it appeared "unlikely" those who came down with COVID-19 a second time would shed enough live coronavirus to spread the disease.

"It does not appear they are infectious to others," said Dr. Bonnie Henry.

But she admitted there is uncertainty.

"We're still learning a lot and it's sometimes complex and we have to keep on top of the different permutations and combinations that happen," she said.

Conway says what this all means is still unclear.

"We do not yet know if people who have been infected once can get infected again and that certainly is the subject of ongoing research right now," said Conway.

Early test results confusing

The answer could have major implications.

Before Garousi was hit with COVID-19 for a second time, members of her immediate family fell ill, too.

Garousi says she has no idea how she contracted the coronavirus. She hadn't been travelling and knew no one else who was sick.

Her early tests were confusing: one positive, one negative, another positive and one inconclusive.

X-rays were ordered. It wasn't until March 24 that she got the results, showing she had spotting on her lungs and signs of pneumonia.

Her doctor phoned her with an official diagnosis of COVID-19, but the late news came as she was already starting to feel better.

The intense body aches, fever and cough were gone. She was, however, left with no sense of taste or smell.

Garousi made it through the accepted 10-day recovery period.

Shilan Garousi, left, and her sister Shnna Mofti sit together at home. Both have tested positive for the coronavirus. (Maggie MacPherson/CBC)

She ended her self-isolation in her Shaughnessy home, where she lives with her extended family, including her daughter, niece, nephew, sister and brother-in-law.

Family falls ill

Her nephew got sick in mid-March, and by late March, Garousi's sister started to feel ill. Both self-isolated in their rooms.

In early April, Garousi's daughter and niece became sick.

On April 7, she took the two girls to hospital for treatment. After returning home, Garousi herself started to exhibit symptoms once again.

The major symptoms lasted just four days.

She was tested again for COVID-19 and received a phone call saying she was positive.

Garousi says Vancouver Coastal Health (VCH) is now monitoring the family on a daily basis to check on their recovery — and any signs of reinfection.

A statement from VCH late Wednesday said the health authority "has no evidence" anybody within its region has been infected twice by COVID-19. The authority has seen more than 800 cases of the illness, to date.

"Most cases are mild and people recover within 10 days of symptom onset, but we know symptoms may last longer for some people," an email statement to CBC News said.

'We're making this up as we go'

After her experience, Garousi believes the solution might be to test all post-COVID-19 patients for antibodies to see if they've built up potential resistance to the disease — or not.

And whether they remain contagious — or not.

Dr. Brian Conway is the medical director of the Vancouver Infectious Diseases Centre. He says Garousi's case is puzzling and there are lessons to learn from it. (Christian Amundson/CBC)

"Hopefully this will be a solution or a clearer answer for us," she said.

Conway confirms there could be valuable lessons from this case, likening it to the early days of HIV when he and other scientists were trying to understand a baffling contagious illness.

"I think of it a little bit as we're paving the landing strip for an airplane that's already approaching the airport," said Conway. "We're making this up as we go along.

"These kind of clinical observations are going to be very helpful to us going forward."

Whether Garousi had a recurrence of COVID-19, or became reinfected from her family, she worries there could be implications for everyone.

"It's scary if I got to be infected by the other family members. And I really hope it's not the case because then we are in bigger trouble than we think we are."