Connect with us

Business

Immune but infectious: Can someone vaccinated against COVID-19 still spread the virus? – Global News

Published

 on


As the cross-Canada roll-out of COVID-19 vaccines continues this week, it’s still unclear whether the injections can actually prevent the spread of the virus.

While both the Pfizer-BioNTech and Moderna products have been shown to be about 95 per cent effective at preventing symptomatic COVID-19 illness, there is not much evidence they can protect those around the person who got the shots.

“Yes, you are still contagious,” Dr. Hana El Sahly told Global News.

El Sahly was one of the lead investigators for Moderna’s late-stage COVID-19 vaccine trial. She says the novel coronavirus can live in the nasal passage for weeks, meaning a vaccinated person could still infect others, even if they don’t get sick. But there was one promising result in the study.

“We did find, in the short term, that those who got the vaccine were less likely to carry [the virus], but the numbers were really small,” El Sahly said.

Story continues below advertisement

Read more:
Advocates call for targeted approach to address COVID-19 vaccine hesitancy in Canada

Both the Moderna and the Pfizer vaccines require people to get two doses, about a month apart, to be effective.

Twenty-nine days after their first dose of Moderna, 14 study participants were found to be carrying the virus — versus the 38 people who received a placebo.

“It’s a signal in the right direction, but nonetheless it cannot be interpreted that the vaccine prevents transmission.”


Click to play video 'Alberta’s COVID-19 vaccine rollout rate and the plan to ramp it up'



2:02
Alberta’s COVID-19 vaccine rollout rate and the plan to ramp it up


Alberta’s COVID-19 vaccine rollout rate and the plan to ramp it up

Dr. Jason Kindrachuk, Canada Research Chair in Emerging Viruses, explains the mRNA-based vaccine teaches our immune system to fight the virus, but it doesn’t block it from entering our body.

“People may be able to still get infected even though they’re vaccinated, but it’s a sub-clinical infection — so they don’t feel sick, they don’t have any symptoms, but they may still be able to transmit,” said Kindrachuk.

Story continues below advertisement

Read more:
How long will the COVID-19 vaccine protect you? Here’s what we know so far

Ongoing research will determine if any COVID vaccine can actually prevent transmission. That will require “collecting a lot of nose swabs on a lot of people,” according to El Sahly.

While asymptomatic carriers are less likely to spread the virus than someone who is coughing and sneezing, masks, distancing and hand-washing will still be critical in 2021 until most Canadians can be vaccinated.

“As we build up that immunity in the public, there is lower and lower… ability for the virus to be able to leap from one person to another,” Kindrachuk said.

Some experts suggest at least 70 to 75 per cent of a population will have to be immunized to control the spread of the virus.

That said, the percentage of the Canadian population that needs to be vaccinated in order to reach confidently herd immunity is unknown, according to Canada’s chief public health officer Dr. Theresa Tam.

“We have an assumption that you will probably need 60 to 70 per cent of people to be vaccinated. But we don’t know that for sure … that’s modelling,” Tam told a media conference on December 4.


Click to play video 'How Canada’s COVID-19 vaccine rollout plan is unfolding'



2:18
How Canada’s COVID-19 vaccine rollout plan is unfolding


How Canada’s COVID-19 vaccine rollout plan is unfolding – Dec 14, 2020

Still, the vaccines are providing some comfort for stressed health-care workers. Pediatric emergency physician Samina Ali received her first dose of the Pfizer vaccine on Jan. 2.

Story continues below advertisement

“It was just so much overwhelming relief… it felt like… as a community, as a world, this was a sign that we were on the way to healing,” Dr. Ali said.

Read more:
Alberta’s COVID-19 vaccine rollout rate and the plan to ramp it up

How Pfizer’s and Moderna’s mRNA-based COVID-19 vaccines work

A vaccine is generally made up of a weakened or a dead virus, which, once injected, prompts the body to fight off the invader and build immunity.

Both Pfizer and Moderna’s candidates have been manufactured using mRNA-based technology, a relatively new way to make vaccines.

Instead of injecting a deactivated form of the virus, the mRNA vaccine uses a component of the virus DNA called messenger RNA that basically contains the genetic instructions for the human body to make the specific spike protein of the coronavirus.

By doing this, the immune system learns to recognize and respond to that specific protein, meaning it can more quickly mount a response if the virus enters the body. The mRNA, however, does not modify a person’s DNA or genetic makeup.

“When your body actually sees the real virus, then you have the weapons already in place — the antibodies and the cells that know this virus that can recognize it — and can kill it faster,” Dr. Donald Vinh, an infectious disease specialist and a medical microbiologist at the McGill University Health Centertold Global News.

Story continues below advertisement

Read more:
AHS ‘actively recruiting’ more staff to help with COVID-19 immunization

According to the data from the clinical trials, Pfizer’s vaccine, which is 95 per cent effective, can offer partial protection as early as 12 days after the first dose.

That protection can last for at least two months, according to Vinh. A second dose is then required to achieve the vaccine’s full potential.

The Moderna vaccine, which also requires a second shot, has shown to be 94 per cent effective.


Click to play video 'Health Canada approves Moderna’s COVID-19 vaccine'



3:07
Health Canada approves Moderna’s COVID-19 vaccine


Health Canada approves Moderna’s COVID-19 vaccine – Dec 23, 2020

— With files from Saba Aziz, Global News

© 2021 Global News, a division of Corus Entertainment Inc.

Let’s block ads! (Why?)



Source link

Continue Reading

Business

What’s behind the EU-AstraZeneca vaccine row? – Al Jazeera English

Published

 on


The European Union and AstraZeneca are engaged in a bitter row over the United Kingdom-based pharmaceutical giant’s supply of coronavirus vaccines to the bloc.

The dispute began last week when AstraZeneca, a British-Swedish company, said it would cut supplies to the EU in the first quarter of this year, citing production issues.

Crisis talks between the pair on Wednesday failed to achieve a breakthrough, prompting fears the argument over how many doses the EU will receive could continue.

The EU contract with AstraZeneca is an advance purchase agreement for the supply of at least 300 million doses, delivered in stages, provided the vaccine is approved as safe and effective.

The dispute has raised concerns about the international competition for limited supplies of the shots, which are hoped to ease the COVID-19 pandemic.

What caused the EU and AstraZeneca row?

Last week, AstraZeneca, which partnered with the UK’s Oxford University to develop its vaccine, said it would cut supplies to the EU in the first quarter of this year, blaming production issues at European manufacturing plants.

An EU official said that meant the 27-member bloc would receive 60 percent fewer doses than initially agreed, down from 80 million to 31 million doses overall in the first three months of 2021.

The news came as a body blow to the EU, which has been slow in rolling out vaccines compared with some other regions and countries, especially the UK, a former member state.

The bloc has signed deals for six different vaccines, but so far its medicines regulators have only authorised the use of two – by Pfizer-BioNTech and Moderna.

The European Medicines Agency is expected to greenlight the AstraZeneca vaccine on Friday.

What has each side said?

Following Wednesday’s talks, EU Health Commissioner Stella Kyriakides said there was still a “continued lack of clarity” from AstraZeneca on the delivery schedule and called on the company to detail how it would supply the bloc with reserved vaccine doses.

“We will work with the company to find solutions and deliver vaccines rapidly for EU citizens,” she said in a post on Twitter.

A spokesman for AstraZeneca said after the meeting that the company was committed to “coordination”.

But Pascal Soriot, AstraZeneca’s chief executive, rejected the EU’s assertion that the company was failing to honour its delivery commitments.

Soriot said vaccine delivery figures set out in AstraZeneca’s contract with the EU were just targets.

“Our contract is not a contractual commitment, it’s a best effort,’’ Soriot told Italian newspaper La Repubblica on Tuesday. “Basically, we said we’re going to try our best, but we can’t guarantee we’re going to succeed.”

Soriot also told reporters that vaccines meant for the EU were produced in four plants in Belgium, the Netherlands, Germany and Italy.

But European Commission officials said on Wednesday that the bloc’s contract with AstraZeneca stipulated that the company had also committed to providing vaccines from two factories in the UK.

The EU’s contract with AstraZeneca is confidential and cannot be released without the agreement of both sides. The bloc has asked the company for permission to release the contract.

How will the argument be resolved?

As of yet, it is unclear how the dispute will be settled.

The EU’s Kyriakides said on Wednesday that AstraZeneca must “live up to its contractual, societal and moral obligations” and deliver the vaccine in the quantities, and by the deadlines, originally set out by their agreement.

Kyriakides added that the firm should divert stock from its UK facilities if it it is unable to meet commitments from factories in the EU.

But a senior UK government minister said on Thursday the country’s supply of vaccines from AstraZeneca must not be interrupted.

“It is the case that the supplies which have been planned, paid for and scheduled should continue,” the Conservative Party’s Michael Gove told the BBC. “Absolutely, there will be no interruption to that.”

Let’s block ads! (Why?)



Source link

Continue Reading

Business

Ontario extends 2nd dose of Pfizer COVID-19 vaccine to 35 days due to delays – CityNews Toronto

Published

 on


The province’s top doctor has once again revised the timing of when people can get the second dose of the COVID-19 vaccine.

In a memo sent to hospital CEOs and Medical Officers of Health on Wednesday, Ontario’s Chief Medical Officer of Health Dr. David Williams has recommended extending the dosing interval for the second shot of the Pfizer-BioNtech vaccine to 35 days and no more than 42 days.

Previously, the province sent out guidance that the second shot be given anytime between 21 and 42 days after the first dose was administered.

The recommendation applies to everyone outside of long-term care settings, essential caregivers and staff, and First Nations elder care homes, where the second doses are set to be administered between 21 and 27 days later.

“We recognize that this allocation reduction will have significant impact on the current level of vaccine delivery across the province,” Williams said in the memo.

“The extended dosage interval is a direct response to the temporarily reduced vaccine availability from the federal government and uncertainty regarding the stability of supply in the near-term.”

Williams points out that there are no scheduled deliveries of the Pfizer-BioNtech vaccine this week and just over 26,000 doses expected the first week of February. The province says it has yet to receive information on how many doses are to be delivered for the weeks of Feb. 8 and 15th.

Pfizer has advised Canada, and other countries, that delivery of its COVID-19 vaccine would be impacted for several weeks due to work to expand its European manufacturing facility.

Let’s block ads! (Why?)



Source link

Continue Reading

Business

Calgary company begins clinical trials for Canadian-made COVID vaccine candidate – CP24 Toronto's Breaking News

Published

 on


The Canadian Press


Published Tuesday, January 26, 2021 5:47PM EST


Last Updated Tuesday, January 26, 2021 5:48PM EST

A prospective COVID-19 vaccine touted as a made-in-Canada response has begun human clinical trials in Toronto, and the company says it’s already preparing a followup that will target more infectious variants.

Providence Therapeutics of Calgary says if all goes well, it could start manufacturing millions of doses of its first prospective vaccine by the end of the year, guaranteeing a Canadian stockpile that wouldn’t be subject to global supply pressures or competition.

That’s if the formulation proves safe and effective, of course.

Among the challenges of developing a vaccine amid a raging pandemic is the uncertainty of how more infectious variants now emerging will complicate the COVID battle.

Even if successful, by the time Providence Therapeutics releases its vaccine hopeful, much of the country could be in the throes of a more infectious virus that does not respond to this formulation, said company CEO Brad Sorenson.

“We don’t believe that this is going to be resolved by a single vaccine,” said Sorenson, whose biotech also produces a personalized mRNA-based vaccine against cancer.

It’s a challenge now facing Pfizer-BioNTech and Moderna, which have each said its products appear to respond well to the variant initially identified in the United Kingdom, and to a lesser degree, the variant first detected in South Africa.

Moderna said earlier this week it plans to test two booster vaccines aimed at the variant associated with South Africa.

Sorenson said Providence is already internally testing a vaccine candidate that targets the variants, and he hoped to begin clinical trials by the end of the year.

“We believe that there’s going to be a need to be in a position of readiness to be able to respond as these variants are coming up, and to be able to make sure that we have that capacity.”

That doesn’t mean Providence is changing production runs just yet.

Sorenson said the immediate focus is to establish the safety and efficacy of its COVID-19 vaccine, dubbed PTX-COVID19-B and designed in the early days of the pandemic last March.

It uses messenger RNA technology and focuses on the spike protein located on the surface of a coronavirus that initiates infection, similar to the Pfizer-BioNTech and Moderna products.

The trial involves 60 healthy volunteers aged 18 to 25 who will be monitored for 13 months, with the first results expected in February.

The subjects are divided into four groups of 15, three of which will get three different doses. The fourth group gets a placebo.

Sorenson said immediate pandemic efforts should be focused on the novel coronavirus currently devastating many parts of the country.

“It’s a matter of capacity. Right now these variants are there, they’re concerning, and we’re keeping a close eye on it, but that’s not predominantly what the needs of the population are,” said Sorenson.

“Right now the needs of the population are still tied to the primary spike protein virus that’s out there and is ravaging around the world.”

Sorenson said his next vaccine candidate takes a broader approach by attempting to elicit a T-cell response, thereby creating a longer-term vaccine “and cover what we believe would be a lot more variants.”

“We have to prove it out, but we believe that if we are successful that it will allow for a much more durable immunity and a much broader immunity.”

The other goal is to prepare for large-scale manufacturing in Calgary, if all goes well with the trials and approval process.

Sorenson said doses for the Phase 1 trial are being made in Toronto, but the plan is to commercially manufacture the completed vaccine through a contract with the Calgary-based Northern RNA Inc.

That won’t be up and running by the end of the year, Sorenson allowed, so the short-term plan is to send raw materials made in Canada to a plant in the United States that would make the commercial product.

Eventually, the whole process would be completed in Canada, he said.

“We’re building the entire chain within Canada, so we’re not going to run into a problem where this particular input into the vaccine is unavailable,” he said.

Much of this also depends on financial support from the federal government, Sorenson added.

While the National Research Council of Canada has backed Phase 1 trials, Sorenson said he’s awaiting word on further support. He’d also like Ottawa to back Providence’s efforts to address the new COVID variants.

“They’ve already recognized the importance of mRNA technology. What they don’t realize is the power of mRNA technology to be responsive to these challenges that are coming up,” he said.

“Hopefully the politicians and the people that cut the cheques and write the policies that give direction to the bureaucrats will hear that and we’ll start seeing a more concerted approach that looks at a fuller picture.”

Pending regulatory approval, Sorenson said a larger, international Phase 2 trial may start in May with seniors, younger subjects and pregnant people, followed by an even broader Phase 3 trial.

The Providence project is just one of several Canadian efforts underway to develop a COVID-19 vaccine.

The biopharmaceutical company Medicago, based in Quebec City, began clinical trials on its plant-based candidate last July. If successful, the company has said manufacturing would take place in Durham, N.C., until it can complete a large-scale manufacturing facility set for Quebec City.

And last month, Health Canada gave the green light to the Vaccine and Infectious Disease Organization (VIDO) at the University of Saskatchewan to launch its Phase 1 clinical vaccine trial.

Infectious disease expert Jason Kindrachuk, who works with VIDO but is not involved with its vaccine candidate, said a varied vaccine strategy will be key to controlling the pandemic.

“Vaccines are not necessarily a one-size-fits-all and maybe with this pandemic, people are getting a greater appreciation for some of the logistical hurdles of trying to transport vaccines. Cold chain storage is not something most people knew about or thought about prior to COVID and everybody in the community now I think has heard about it,” said Kindrachuk, a visiting scientist from the University of Manitoba and Canada Research Chair.

“This is something that, in regards to vaccine development, we really have to put a lot of thought into as a research community because of the fact that we have to make vaccines that are accessible for the communities that are ultimately going to be treated with them.”

Ontario Health Minister Christine Elliott acknowledged Tuesday that appetite was strong for a homegrown answer but noted Providence was still a considerable ways from offering a viable option.

“First it has to go through the appropriate approval process, go through Health Canada to make sure that it’s going to be satisfactory and safe and efficacious,” said Elliott.

Let’s block ads! (Why?)



Source link

Continue Reading

Trending