Health officials across Canada are rolling out results from the first wave of serology (also known as antibody) testing to try and figure out how many people actually were infected with COVID-19 since the start of the pandemic.
After someone is infected with a virus such as COVID-19, their body develops antibodies that could potentially help fight it the next time they are infected. Therefore, serology testing can give health officials a better idea of the number of people who’ve developed antibodies, which indicates they had contracted the virus at some point, rather than just those who tested positive.
Antibody testing has its flaws. Someone might test negative for the antibodies when their body just hasn’t developed them yet, while people currently infected with COVID-19 may also test negative. Current serology testing also relies on blood donor banks and doesn’t necessarily reflect the entire population.
For example, Canada’s long-term care system has been hardest hit by the virus, and includes a segment of the population unlikely to be donating blood, especially right now. So antibody testing results may not reflect the total impact on that population.
There’s also the issue of timing, many of these test results indicate the spread of the virus two months ago. And scientists are still uncertain on how long antibodies last in the body after someone has COVID-19.
Still, serology testing is a useful resource for health officials when it comes to better understanding how far the virus has spread. Federal officials and Canadian Blood Services announced in June that they had found COVID-19 antibodies at a rate of less than one per cent, using 10,000 samples from across the country, indicating that it was less widespread than some may have thought and preventative measures must remain in place.
Here are what some provinces have found from antibody testing so far:
A new study released this week showed higher rates of COVID-19 antibodies...