Memories of SARS 2: Testing

More about SARS, very much second-hand.

Without testing, we wouldn’t have caught the second outbreak until it had started to spread again. And we could have a third and a fourth outbreak, happily killing doctors and nurses.

Outbreak 1: Let’s kill all the doctors

It didn’t take much testing to get started, because the second person to die walked into the emergency room. So we put his family in quarantine and started interviewing everyone they had been in contact with and isolating them too.

At that point, however, testing became critical.  We didn’t know who was sick. Very quickly, we found out the disease was spreading inside the hospitals, infecting doctors and nurses who worked with anyone who’d been part of the first and any subsequent intubations.

That was even worse: we both needed the doctors and nurses to treat the SARS patients, but at the same time we risked infecting all the other patients and staff in the hospital.

Fortunately the Hospital for Sick Children, Mount Sinai, Sunnybrook and Women’s had specific expertise in dna-based testing, and ran literally thousands of real-time “reverse transcription–polymerase chain reaction” tests, identifying the SARS virus itself from fragments of its dna in a matter of minutes, not hours or days.

With fast tests and multiple hospitals running them in parallel, it became possible to identify people who were infected, often before they became sick. Now we could tell which nurses and doctors were safe to work with non-SARS patients.

By then the disease was spreading rapidly through the community. the community health nurses could start adding tests to their interviewing, and isolating only the people they knew were developing the disease. Before that, all they could try to so was isolate everyone who had met anyone who had met anyone with the disease.

Better, they could catch people who had the disease, but had no symptoms. Those were dangerous: they didn’t know they were ill, but they could infect others.

About then, we had developed blood tests, which could be used in huge quantities and processed easily. They only worked if you had been ill long enough to start developing antibodies to the disease, but they were cheap and easy to apply. And they told us who had recovered from SARS, and was safe to release.  Better, they told us who was now immune, and could be asked to volunteer to help SARS patients.

Outbreak 2: As soon as you relax…

A week after the World Health Organization declared Toronto safe, a patient in St Johns  recovery hospital was tested and found to have SARS. He was recovering from previous unrelated surgery, and had contacted SARS before going for rehabilitation.

Exactly how it happened is still unknown, but because the disease could and did spread before the patients showed symptoms, we really needed tests that would detect the disease before the patient felt ill.

So the hospitals went back into full emergency mode, separating SARS patients into a few specific hospitals and sending everyone else to uninfected ones.

Slowly we isolated enough patients that the spread slowed to a trickle, and then a stop, without exhausting our hospital resources, and with only a moderate loss of life

Implications for us, now

With good testing, especially of the virus DNA, we slowed the spread of SARS. The more we can slow an outbreak, the more we can “flatten the curve”, until we have enough understanding,  antivirals, hospital rooms, ventilators, and eventually vaccines. 

Without, we can look forward to the life of Thomas Hobbes’ savage: “solitary, poor, nasty, brutish and short”.

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