Jason Herring
The Foothills hospital was photographed on Wednesday, May 19, 2021.Photo by Gavin Young/Postmedia
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An outbreak of the COVID-19 Delta variant at a Calgary hospital is raising concerns about the effectiveness of vaccines at containing the strain, which is spreading quickly in the city.
But most people infected with the highly contagious variant strain, first discovered in India, are only experiencing mild illness, Alberta Health Services says.
The outbreak, in two units of Foothills Medical Centre, has seen 16 patients and six health-care workers test positive for the Delta variant. One of the patients was admitted to intensive care.
All but one case in the outbreak are thought to have been acquired in the hospital.
According to reports from the United Kingdom, where the strain is driving recent spikes in COVID-19 cases, the Delta variant is more resistant to vaccines than other strains.
There, data showed both the Pfizer and AstraZeneca vaccines are only 33 per cent effective against symptomatic disease from the Delta variant following a first dose. That effectiveness rises above 80 per cent after the second dose.
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Among the 22 Delta cases in the Foothills outbreak, 11 involved people who had already received their second dose of COVID-19 vaccine at least 14 days prior. Another eight had only one vaccine dose. The province is now monitoring those cases.
I want to emphasize that we do see a small number of people who have completed their immunization that can still go on to get ill, Dr. Deena Hinshaw, Albertas chief medical officer of health, said Tuesday.
While we can see a few cases that have broken through the vaccine, the vast majority of people who are vaccinated will have protection.
On Twitter Friday, Hinshaw stressed vaccines do not make us invincible but offer high levels of protection.
Dr. Leyla Asadi, a University of Alberta infectious disease physician, said the outbreak is certainly concerning but cautioned against drawing conclusions on the effectiveness of vaccines against the Delta variant based on the limited data available.
We cant use this one small sample size of interconnected cases (with potentially the same source of exposure or same environmental conditions, i.e. ventilation) to make vaccine effectiveness determination, Asadi said on Twitter Friday.
She added the virus is characterized by superspreader events, meaning a small cross-section of people will be involved in the majority of infections.
Cases will be clustered and I suspect it follows that breakthrough infections will also be clustered, she said.
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The Delta variant continues to grow in Alberta, but the Calgary area is the hot spot for spread. The province reported 40 new cases of the strain, 34 of which were in the AHS Calgary zone. That zone accounts for 223 of Albertas 262 lab-confirmed Delta cases.
Alberta resumed screening of all new COVID-19 cases for variant strains at the start of June, after ceasing the practice for about a month as labs were overwhelmed by high case counts during the pandemics third wave.
Hinshaw said vaccine efficacy rates against the Delta variant show the importance for Albertans to become fully immunized against COVID-19 by getting their second shot.
The province opened up second dose bookings ahead of schedule Thursday, offering appointments to all Albertans who received their first dose in April or earlier.
That announcement resulted in Albertas highest-demand day yet for booking appointments, with 158,092 booking a shot through AHS. Of those bookings, 154,604 were for second doses.
Those numbers only include jabs scheduled through AHS, with pharmacy numbers tracked separately.
Late Friday, the province reported it has administered 3.27 million doses of vaccine, with 68.2 per cent of Albertans age 12 and over having received at least one shot and 18.8 per cent of eligible Albertans now fully vaccinated.
Second shot uptake continues to grow, with 77 per cent of the most recent batch of jabs reported being second doses.
One Albertan who got their second shot Friday was Calgary Mayor Naheed Nenshi, who encouraged those who were first immunized in April to book as soon as possible.
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If youve got your first, its time for your second, and Im telling you right now, it feels great, Nenshi told reporters after getting the shot at a local pharmacy.
Mayor Naheed Nenshi receives his second does of the COVID-19 vaccine at a pharmacy in southwest Calgary on Friday, June 11, 2021.Brendan Miller/Postmedia
For those who still havent received their first shot, AHS is offering walk-in immunizations at the Genesis Centre in northeast Calgary this Tuesday and Wednesday from 9 a.m. to 5 p.m., with up to 500 doses of Pfizer vaccine offered each day.
Its the latest in a series of drop-in immunization efforts for first doses, which included a community-led clinic at Village Square Leisure Centre that saw more than 2,200 first doses given last weekend, and a sparsely attended walk-in clinic at the Telus Convention Centre over the past three days.
Also on Friday, Alberta reported 170 new cases of COVID-19 from about 6,700 tests, representing a 2.5 per cent positivity rate.
Its the first time Alberta has logged a positivity rate of 2.5 per cent or below since Oct. 23, more than seven months ago.
Hospitalizations from the virus fell to 296 from 306 the previous day. Of those patients, 79 are in ICUs, down from 81.
Three more deaths from the virus were also reported, including two men in their 60s and 80s from the Calgary area. The toll from the pandemic in Alberta is now 2,265.
With files from Madeline Smith
jherring@postmedia.com
Twitter: @jasonfherring
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