Q & A: What you need to know about the COVID-19 Delta variant
Health officials in Waterloo Region say the recent spike in COVID-19 cases is being driven by the new Delta variant.
CTV Kitchener spoke with Dr. Prabhat Jha, an epidemiologist at the University of Toronto's Dalla Lana School of Public Health and Director of the Centre for Global Health Research at St. Michael's Hospital, for an in-depth primer on the new Delta variant.
WHY IS THE DELTA VARIANT SO CONCERNING?
"The Delta variant is a concern because it is more infectious, that seems to be clear. It transmits easier from one person to the other," Dr. Jha said. "There is some suggestion it might actually be more deadly or cause disease more often."
He said although the overall number of COVID-19 infections in Ontario is declining, the Delta variant is making up a greater proportion of new cases.
"The bad news is it's more sticky and more transmissible," he said.
Some experts have said the Delta variant is about 50 per cent more transmissible than the Alpha variant.
Think of the virus as needing a key to enter your cells, Dr. Jha suggests. That key is what's commonly called the spike protein, or the S1 protein.
COVID-19 is mutating as the pandemic persists globally to get a "competitive advantage" and become more infectious.
"If you can make that a better key, you're more likely to open the door," into human cells, Dr. Jha said. "This is what the mutations are selecting for."
HOW IS THE DELTA VARIANT DETECTED?
COVID-19 is detected using a polymerase chain reaction (PCR) test, which looks for the virus.
Once a sample is confirmed as positive, the next step is to screen for variants of concern. Dr. Jha says the initial screening test used in Canada currently, another form of a PCR test, searches for two specific mutations that point to the case being a variant.
Right now, he said this screening test can detect the Alpha and Beta variants or if the virus is an unknown variant.
"The initial screening test is enough to pick up whether it is the Alpha or the Beta as well, but doesn’t tell you it’s a Delta," Dr. Jha said. "To do that, you have to sequence the whole virus."
Unfortunately, he said that's a lengthier process – leading to a lag in reporting the number of confirmed Delta cases.
"We could do with better evidence and more sequencing and seeing what is the distribution in various parts of the province," Dr. Jha said.
He said work is underway to allow the screening test to quickly identify the Delta variant.
"Science has to work overtime."
ARE VACCINES EFFECTIVE AGAINST DELTA?
Short answer: yes.
Dr. Jha points to studies out of the United Kingdom that show two vaccine doses provide about 90 per cent protection against hospitalization from the Delta variant.
"The good news is with double vaccination, the chance of getting hospitalized or dropping dead of the Delta variant is very low," he said. "Two doses are far better than one."
He said Ontario's strategy of speeding up second dose vaccine appointments in COVID-19 hot spots is the correct one.
"The strategy that has now been adopted is in hot spots make sure people get two doses," Dr. Jha said. "They're getting the numbers way up and really pushing second doses in hot spots. I think that’s absolutely right."
Still, he warns further evidence is needed to confirm if vaccines are also effective at preventing further transmission of the Delta variant.
WHAT ABOUT FUTURE VARIANTS?
The more COVID-19 continues to spread globally, the greater the risk for future variants, Dr. Jha said.
"Think of it as you’ve got more kettles on the go or more soup bowls going, so out of them is going to come more variants," he explained. "We won't control variants unless we control community transmission worldwide."
He said variants will try to evolve to escape vaccines.
"The big worry is, what about, not the Delta, but the Epsilon that picks up on the success of the Delta and says, 'I can do better,'" Dr. Jha said. "If it can get in the door and not have the vaccine whack it, that would be a big problem."
As variants develop when spreading among unvaccinated people, he said it's imperative to get COVID-19 vaccine jabs into arms everywhere.
"To address that, the only strategy is to vaccinate the world," he said. "Otherwise, it's just a matter of time before a variant comes back and our vaccines don’t work."