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Study offers 'promising' evidence that at least 1 COVID-19 vaccine may curb virus transmission – CBC.ca

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Real-world findings are starting to back expectations for the level of protection provided by several leading coronavirus vaccines, but there’s still a burning question among scientists: Could the shots actually reduce virus transmission as well?

New research out of Israel offers early clues that at least one vaccine — the mRNA-based option from Pfizer-BioNTech, which is also being used here in Canada — may lead to lower viral loads, suggesting it might be harder for someone to spread the virus if they get infected post-vaccination.

In a study released publicly on Monday as an unpublished, non-peer-reviewed preprint, a team of researchers from the Israel Institute of Technology, Tel Aviv University and Maccabi Healthcare Services found the viral load was reduced four-fold for infections that occur 12 to 28 days after a first dose of the vaccine.

“These reduced viral loads hint to lower infectiousness, further contributing to vaccine impact on virus spread,” the researchers wrote.

Virologist Jason Kindrachuk, an assistant professor in the department of medical microbiology at the University of Manitoba, said it’s been a waiting game to figure out whether the protection from illness offered by mRNA vaccines might also curb transmission — a key tool for winding down the pandemic.

“So the data from this, I think, is important,” he said. “It doesn’t answer all the questions, but it starts to tell us that there actually might be some added benefit to these vaccines beyond just reducing severe disease.”

Toronto-based infectious disease specialist Dr. Isaac Bogoch, a member of Ontario’s vaccine task force, agreed these early findings — which still require peer-review — aren’t a scientific “home run,” but do offer hope in the fight against COVID-19.

“This would point in the direction that people who have been vaccinated, who are still infected, may be less likely to transmit starting at about 12 days after their vaccine,” he said.

‘Significantly reduced’ viral loads

Israel is among the world leaders for COVID-19 vaccination rates, with Maccabi Healthcare Services vaccinating more than 650,000 people by Jan. 25, the paper noted, giving the researchers a large pool of data compared to what exists so far in many other countries. 

The team analyzed COVID-19 test results from roughly 2,900 people between the ages of 16 and 89, comparing the cycle threshold values of post-vaccination infections after a first dose with those of positive tests from unvaccinated patients.

So, what are cycle threshold values, and how does that potentially tie to viral loads and virus transmission?

Standard polymerase chain reaction (PCR) tests for COVID-19 identify the viral infection by amplifying the virus’s RNA until it hits a level where it can be detected by the test. Multiple rounds of amplification may be required — and the cycle threshold value refers to the number of rounds needed to spot the virus.

Toronto-based infectious disease specialist Dr. Isaac Bogoch, a member of Ontario’s vaccine task force, agrees these early findings — which still require peer-review — offer some hope in the fight against COVID-19. (Maggie MacPherson/CBC)

“If you can detect the virus with very few cycles, there’s probably a lot of virus there,” Bogoch explained. “If you need to keep looking and looking and looking and looking for it, it might be there — it’s just a lot harder to find evidence of the virus genetic material.”

A higher cycle threshold, then, usually means there’s less virus genetic material present, which usually translates to people being less contagious, he said.

Based on an analysis comparing post-vaccination test results up to Day 11 to the unvaccinated control group, the Israeli researchers found “no significant difference” in the distribution of cycle threshold values for several viral genes.

That changed by 12 days after vaccination, with the team finding a “significant” increase in cycle thresholds up to 28 days later.

A team of researchers from the Israel Institute of Technology, Tel Aviv University and Maccabi Healthcare Services found the viral load was reduced four-fold for infections happening 12 to 28 days after a first dose of the Pfizer-BioNTech mRNA vaccine. The findings have yet to be peer-reviewed and published in a medical journal. (Evan Mitsui/CBC News)

The result suggests infections occurring 12 days or longer following just one vaccine dose have “significantly reduced viral loads, potentially affecting viral shedding and contagiousness as well as severity of the disease,” the team concluded.

It’s a finding that appears to mimic the efficacy of the Pfizer-BioNTech vaccine in its clinical trials, which offered some early protection starting 12 days after the first dose and fully kicks in a week after the second shot, with a reported efficacy of around 95 per cent.

More research needed, experts say

The observational study was not a randomized controlled trial — meaning researchers couldn’t conclude a direct cause-and-effect relationship — and has not yet been published in a scientific journal. The research also has notable limitations, its authors acknowledged. 

For one, the group of vaccinated individuals may differ in key ways from the demographically matched control group, such as their general health. The study also didn’t account for variants of the virus that may be associated with different viral loads, the team wrote.

Indeed, those variants are already proving to be roadblocks in the fight against COVID-19, with concerns ranging from higher transmissibility to reduced vaccine efficacy, including concern in South Africa and beyond after a small and yet-to-be-published study suggested the Oxford-AstraZeneca vaccine offered minimal protection against mild infection from the country’s now-dominant B1351 variant. 

With those concerns in mind, experts who spoke with CBC News about the Israeli study stressed that more research is needed to back up the results on a broader scale, and among diverse populations, before being used to fuel policy changes or current approaches to vaccination efforts.

“The data needs to be reviewed by experts and confirmed that it stands up to the quality that we would want to make a conclusion,” said vaccinologist Alyson Kelvin, an assistant professor at Dalhousie University in Halifax who works with Canadian vaccine developer VIDO-InterVac in Saskatoon.

WATCH | The impact of variants on the race to vaccinate: 

South Africa has halted its rollout of the AstraZeneca COVID-19 vaccine after a study showed it offered minimal protection against mild infection from a variant spreading there. While experts say it’s cause for concern, they say vaccines can be reconfigured to protect against mutations. 2:01

Even so, Kelvin said the data appeared to be treated with the necessary caution, and offers “promising evidence,” while Kindrachuk remains optimistic as well that the findings could prove a useful starting point.

“While we still have to have people using masks, and while we still have to have people distanced, the vaccines may actually also be able to reduce transmission,” he said. 

“So, those trends that we’re hoping to see, in regards to trying to curb community transmission for SARS-CoV-2, may be accelerated with a vaccine — and that will hopefully help us get out of this a little bit sooner.”


The Current21:46Vaccine concerns in South Africa

South Africa is facing another hurdle in its fight against COVID-19 after a new study suggested the Oxford-AstraZeneca vaccine is largely ineffective against the dominant variant spreading in that country. Dr. Rinesh Chetty, who works on the front lines of the pandemic in Durban, South Africa, weighs in on the findings. And Dr. Gerald Evans, an infectious disease specialist at Queen’s University and the Kingston Health Sciences Centre, tells us what it means for Canada’s vaccination efforts. 21:46

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B.C. announces vaccines sites ahead of booking COVID-19 shots appointments Monday – PrinceGeorgeMatters.com

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VICTORIA — Health authorities across British Columbia announced locations for COVID-19 vaccine centres Sunday, the day before some of the province’s oldest residents could start booking appointments to get their first shots. 

Vaccine call centres are set to open Monday morning to make COVID-19 vaccine appointments for people 90 and older, and Indigenous people 65 or older, as well as those who identify as Indigenous elders.

Island Health officials said Sunday 19 community sites across Vancouver Island have been identified to administer COVID-19 vaccines and 25 community sites in the Vancouver Coastal Health region will be used as clinic locations.

The Interior, Northern and Fraser health authorities say they will confirm vaccination sites with people when they book a COVID-19 appointment.

“We recognize that there’s lots of people that are eager to call in and get going (Monday), so just another reminder that please, unless you are in that category of over 90 or Indigenous over 65 or you identify as an elder, please don’t call next week so we can get through this important population,'” said Victoria Schmid, Island Health’s pandemic planner.

“Your turn will come,” she said at a news conference Sunday. “We just need everyone to be patient right now.”

People can contact their health authority and book appointments for themselves or their spouse, and family members or friends are permitted to schedule an appointment on someone else’s behalf, Schmid said.

People will be asked to provide the person’s first and last name, date of birth, postal code and personal health number and will be asked for an email address or text number to confirm the COVID-19 vaccine appointment, she said..

People born in 1936 or earlier can start calling for appointments on March 15 and those born in 1941 or earlier can start scheduling their shots on March 22.

Schmid said she expected the appointments to last about 30 minutes, which includes a 15-minute waiting period following the administration of the vaccine.

She suggested people wear short sleeves to make it easier to give the vaccine and not to forget a mask.

A support person to can accompany people to the vaccine clinic, she said.

Schmid said sites for the community clinics were chosen for their accessibility and comfort and familiarity for Indigenous people.

“Ease of access was really important to us,” she said. “We really tried to keep a travel time to no more than 15 minutes within urban areas. We want to make sure these sites are accessible for individuals with mobility challenges.”

Immunization clinics will also be held at Indigenous friendship centres in Victoria, Port Alberni and Port Hardy, Schmid said.

Vancouver Coastal Health said in a news release its clinics will be located cross Metro Vancouver and the Squamish and Whistler areas and the Sunshine Coast. The clinics will be held at community, friendship, senior and cultural centres and other regional sites.

The health authorities plan to have B.C.’s population of elderly people, ranging in age from 80 to more than 90 years and Indigenous people 65 and older and elders, vaccinated against COVID-19 by April 12, Schmid said.

She said a person 90 years and older who calls next week for a COVID-19 vaccination will get their appointment within one week.

“They have a week to register for the following week’s vaccination appointment,” said Schmid. “After that, we’re going to move to register those over 85 and then moving down the week after to those over 80.”

Island Health’s Dr. Mike Benusic said he’s optimistic about the vaccination rollout.

“The announcements we’re giving right now provide me with such a sense of hope,” he said. “The fact is right now we have 25 times the number of people vaccinated within Island Health than people who have had COVID-19 within Island Health, and we’re only going to see that number sky rocket in the next few weeks and months.”

This report by The Canadian Press was first published March 7, 2021.

Dirk Meissner, The Canadian Press

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Lines open Monday in B.C. to start booking COVID-19 vaccine appointments for seniors – Burnaby Now

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VICTORIA — Health authorities across British Columbia announced locations for COVID-19 vaccine centres Sunday, the day before some of the province’s oldest residents could start booking appointments to get their first shots. 

Vaccine call centres are set to open Monday morning to make COVID-19 vaccine appointments for people 90 and older, and Indigenous people 65 or older, as well as those who identify as Indigenous elders.

Island Health officials said Sunday 19 community sites across Vancouver Island have been identified to administer COVID-19 vaccines and 25 community sites in the Vancouver Coastal Health region will be used as clinic locations.

The Interior, Northern and Fraser health authorities say they will confirm vaccination sites with people when they book a COVID-19 appointment.

“We recognize that there’s lots of people that are eager to call in and get going (Monday), so just another reminder that please, unless you are in that category of over 90 or Indigenous over 65 or you identify as an elder, please don’t call next week so we can get through this important population,'” said Victoria Schmid, Island Health’s pandemic planner.

“Your turn will come,” she said at a news conference Sunday. “We just need everyone to be patient right now.”

People can contact their health authority and book appointments for themselves or their spouse, and family members or friends are permitted to schedule an appointment on someone else’s behalf, Schmid said.

People will be asked to provide the person’s first and last name, date of birth, postal code and personal health number and will be asked for an email address or text number to confirm the COVID-19 vaccine appointment, she said..

People born in 1936 or earlier can start calling for appointments on March 15 and those born in 1941 or earlier can start scheduling their shots on March 22.

Schmid said she expected the appointments to last about 30 minutes, which includes a 15-minute waiting period following the administration of the vaccine.

She suggested people wear short sleeves to make it easier to give the vaccine and not to forget a mask.

A support person to can accompany people to the vaccine clinic, she said.

Schmid said sites for the community clinics were chosen for their accessibility and comfort and familiarity for Indigenous people.

“Ease of access was really important to us,” she said. “We really tried to keep a travel time to no more than 15 minutes within urban areas. We want to make sure these sites are accessible for individuals with mobility challenges.”

Immunization clinics will also be held at Indigenous friendship centres in Victoria, Port Alberni and Port Hardy, Schmid said.

Vancouver Coastal Health said in a news release its clinics will be located cross Metro Vancouver and the Squamish and Whistler areas and the Sunshine Coast. The clinics will be held at community, friendship, senior and cultural centres and other regional sites.

The health authorities plan to have B.C.’s population of elderly people, ranging in age from 80 to more than 90 years and Indigenous people 65 and older and elders, vaccinated against COVID-19 by April 12, Schmid said.

She said a person 90 years and older who calls next week for a COVID-19 vaccination will get their appointment within one week.

“They have a week to register for the following week’s vaccination appointment,” said Schmid. “After that, we’re going to move to register those over 85 and then moving down the week after to those over 80.”

Island Health’s Dr. Mike Benusic said he’s optimistic about the vaccination rollout.

“The announcements we’re giving right now provide me with such a sense of hope,” he said. “The fact is right now we have 25 times the number of people vaccinated within Island Health than people who have had COVID-19 within Island Health, and we’re only going to see that number sky rocket in the next few weeks and months.”

This report by The Canadian Press was first published March 7, 2021.

Dirk Meissner, The Canadian Press

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Hamilton records two more COVID-19 deaths over the weekend – TheSpec.com

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Hamilton recorded two new COVID-19 deaths over the weekend as active case counts crept back above 400.

The city reported 79 new coronavirus cases and 431 active cases Sunday, up from 35 and 378 Saturday.

It marks the first time active cases have increased since Feb. 28.

One person in their 60s and one person in their 70s were reported to have died Saturday and Sunday, respectively. A total 287 people in Hamilton have died due to complications with COVID-19.

Presumed cases of fast-spreading coronavirus variants in the city crossed the 100-mark this weekend.

On Sunday, public health reported 106 presumed cases of the variants, which are more contagious and believed to cause more severe illness.

That’s up 18 from the 88 presumed cases reported Friday and nearly triple the 37 presumed cases reported Feb. 26.

All coronavirus cases in Ontario are screened for the variants that first appeared in the U.K., South Africa and Brazil. Cases that screen positive for a variant are then sent to a lab for confirmation. Nearly all of those cases end up being confirmed, according to Hamilton’s medical officer of health.

To date, Hamilton has had four confirmed cases of the B.1.1.7 strain, which originated in the U.K.

The city’s active outbreak total is now at 28 after four outbreaks were declared and three were ended over the weekend.

The Meadows Long Term Care Home in Ancaster entered outbreak protocol Thursday after one staff member became infected with COVID-19.

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One teacher and one student tested positive at Orchard Park Secondary School on Friday.

Three staff members at Red Hill Toyota at 2333 Barton St. E. were reported to be infected in an outbreak declared Saturday.

Outbreaks at I.H. Mission Service and Aug. 8 on Wilson Street were ended Saturday. An outbreak at Juravinski Hospital Unit M2 — where eight people were infected and two died since it was declared Feb. 19 — ended Sunday.

The new COVID cases reported over the weekend bring Hamilton’s pandemic total to 10,801. Ninety-two per cent of those — 9,909 — have recovered.

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