Experts say the number of COVID-19 cases caused by the delta variant is doubling every seven to 10 days in British Columbia.
Professor Sarah Otto of the University of British Columbia said the variant, which first appeared in India, replaces the alpha variant that originated in the UK.
“Delta is now the most common variant in the province, doubling in frequency every week for alpha,” said Otto, an expert in the university’s department of zoology on mathematical models of pandemic growth and development.
“The delta variant increases viral load by about a thousand-fold, making it easier to catch and transmit,” she added.
COVID-19 cases in British Columbia continued their upward trajectory as the province reported more than 700 infections Tuesday over a four-day period, with more than half of cases in the interior where the vaccination rate is lower.
Paul Tauber, a professor of mathematics at Simon Fraser University, said the delta variable is a “large part” of the reason for the increase in COVID-19 case numbers.
easing restrictions He said reopening the economy also contributed to growth.
If an alpha variant infects two people on average, delta infects three, he said, “and that’s bad news.”
The good news, he said, is that areas with higher vaccination rates show fewer infections, even with a delta variant.
Tapper said the Vancouver Coastal Health District has a vaccination rate of about 80 percent, while the Inland Health District is at 65 percent — and that’s reflected in the COVID-19 case numbers.
Delta and the fourth wave
The emergence of the delta variable is stronger than scientists expected, and the next wave of the pandemic in Canada has the potential to be similar to what is happening in the United States if there are special measures such as mask states not being reintroduced, said Dean Carlin, a professor of physics at the University of Victoria.
“Right now, in Alberta and British Columbia, it’s very clear that Delta is starting to play a big role,” Carlin said.
He said the exact path and intensity of growth will become clearer as more data comes in over the next few weeks.
Otto said BC has started a fourth wave of COVID-19 infections, but how high and how fast it rises depends on everyone’s behavior.
She said the two things people can do to prevent the wave from rising “too high” are to get vaccinated and avoid crowded indoor places without a mask.
The county and country will continue to see such waves as new, more transmissible variants emerge, but Otto noted that “vaccines really do protect people from the worst damage from this disease.”
Most of the infections are likely to be among the unvaccinated population, said Caroline Cullen, a professor of mathematics at Simon Fraser University.
“And they of course have the same risks of being hospitalized as they always have, or maybe more with Delta because it can be more severe and [have] ‘Higher viral loads,’ she said.
While vaccines are about 90 percent effective against the coronavirus, Tapper said there will still be some people who get sick and pass it on to others. He said that a higher degree of immunity could be achieved by vaccinating children under 12 years of age.
Health Canada has not yet approved a vaccine for children under 12 years of age.
“Children when they are vaccinated can contribute to herd immunity, and that makes others safer,” Taber said. It certainly makes sense for there to be some restrictions until a higher vaccination rate is reached, Taber said.
“So anything that saves us time, allows us to reduce the number of infections before we raise our vaccination numbers, it makes sense,” he said.