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What do we know about breakthrough COVID cases? Experts break down the science – Powell River Peak

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As COVID-19 cases rise through parts of the country, experts expect the number of infections among fully vaccinated people will increase with them. But that doesn’t mean the vaccines have stopped working.

Cases among fully vaccinated individuals — dubbed breakthrough infections if they occur at least two weeks following a second dose — are rare, experts say, even against the more transmissible Delta variant. And the chance a fully vaccinated person would get seriously ill or die following a COVID-19 infection is even less likely, they add.

“To date, the vaccines are doing exactly what we would expect them to be doing,” said Dr. Isaac Bogoch, an infectious disease physician with the University of Toronto. 

“They reduce people’s risk of getting the infection, they significantly reduce the risk of people getting very sick and landing in hospital, and there’s also good growing data demonstrating that vaccines reduce the degree to which someone is contagious.”

So what do we know about breakthrough infections? The Canadian Press asked Bogoch and other health experts to break down the science:

HOW OFTEN ARE BREAKTHROUGH CASES HAPPENING? 

Data from Public Health Ontario showed breakthrough cases accounted for less than one per cent of all COVID-19 infections in the province from Dec.14, 2020 to Aug. 7, 2021. 

But as the proportion of vaccinated Canadians grows, so too will the number of vaccinated people exposed to the circulating Delta variant. And experts say we’ll likely see more breakthrough cases.

Those without shots are still significantly more vulnerable, though: Ontario public health data found unvaccinated individuals were about eight times more likely to contract COVID-19 in the past 30 days. Recent cases in British Columbia showed a 10-times higher rate of infection among unvaccinated people and a 17-times higher hospitalization rate.

Dr. Sumon Chakrabarti, an infectious disease physician in Mississauga, Ont., said that while Delta is a problem, the vaccines are still offering excellent protection.

“There’s just so much more of Delta right now so we’re seeing people who are getting COVID after they have the vaccine — but they’re almost uniformly getting mild disease,” he said. “As time goes on we’ll see more (breakthroughs) because we’re looking for them.

“But you have to compare it to the vast number of fully vaccinated people being exposed to COVID and not (catching it).”

A U.K. study from July suggested vaccine effectiveness dipped against Delta compared to the Alpha variant, offering between 67 and 88 per cent protection against infection. But effectiveness against death and severe disease has remained high.

WHO IS MORE LIKELY TO SUFFER SERIOUS BREAKTHROUGH INFECTIONS?

Though it doesn’t happen often, some fully vaccinated people have either required hospitalization or intensive care or died following a breakthrough infection.

Bogoch said emerging worldwide data suggests those who suffer serious breakthrough outcomes are likely to have other risk factors for severe disease.

“This is usually older or frail adults or immunocompromised individuals,” he said. “And these are people that won’t mount the same degree of an immune response to vaccination compared to younger cohorts.”

Since those segments of the population were also among the first prioritized for vaccination when Canada’s rollout began in December, some experts say waning immunity may be at play for certain groups.

A pre-print study from immunologists at McMaster University suggests those in long-term care could soon need a booster shot to amplify their protection.

“In the general population, it is not believed that we have reached that waning immunity,” said Dawn Bowdish, a co-author of the pre-print study which is currently under review. “In long-term care and in the vulnerable, yes, they’re reaching waning immunity, but they never have immune responses that last as long.”

Chakrabarti said most studies on immune longevity look at antibody levels over time. But while antibodies decrease, T-cell responses linger much longer to continue to help fight off severe infection.

“Antibodies are like a brick wall. They’re strong but with enough force you can knock them down,” he said. “But the kind of long-term immunity you have with your T-cells, that’s like a concrete wall. That’s not something that easily drops.”

CAN BREAKTHROUGH INFECTIONS LEAD TO FURTHER TRANSMISSION?

Recent data from the United Kingdom showed that some fully vaccinated COVID-19 patients had similar viral loads to unvaccinated people who contracted the virus. While that would seem to suggest vaccinated people are just as contagious, experts say that’s not the case.

Bowdish said further studies have indicated viral load drops much quicker in fully vaccinated people compared to those unvaccinated: “So you might have one day of being infectious versus five,” she explained.

“Right now we’re seeing Delta is just as contagious as chicken pox in unvaccinated people,” Bowdish said. “In vaccinated people, it’s probably closer to influenza…. So a fully vaccinated person, there’s still potential to transmit, but it will be a lot less.”

Bowdish added that the amount of viral load someone carries around doesn’t necessarily translate to how infectious the person is. 

She pointed out that studies during the first wave, before Delta emerged, suggested children carried high loads of virus but weren’t as contagious as adults. She said the presence of symptoms and the behaviour of the host — are they sneezing and surrounded by people?— impact transmission more than viral load itself. 

Chakrabarti added viral load doesn’t always indicate the presence of live virus, and since vaccinated people likely won’t have symptoms, they also likely won’t become super-spreaders. 

HOW DO WE STOP BREAKTHROUGH CASES?

Some experts believe the COVID-19 virus will become endemic, with small, seasonal waves continuing to pass through predominantly unprotected populations. That means it will be hard to stop breakthrough infections entirely.

Bogoch said the best way to halt spread among both vaccinated and unvaccinated groups is to continue with added layers of protection, including mask-wearing and limits on indoor gatherings, to “stop infections in the community.”

“Right now, we have to vaccinate plus have other mitigation efforts in place simultaneously,” he said. “We’ll get out of this pandemic. We’re just not there yet.”

This report by The Canadian Press was first published Aug. 26, 2021.

Melissa Couto Zuber, The Canadian Press

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FDA panel rejects plan to offer Pfizer booster shots against COVID-19 to most Americans – WAGM

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WASHINGTON (AP) — Dealing the White House a stinging setback, a government advisory panel overwhelmingly rejected a plan Friday to give Pfizer COVID-19 booster shots across the board, and instead endorsed the extra vaccine dose only for those who are 65 or older or run a high risk of severe disease.

The twin votes represented a heavy blow to the Biden administration’s sweeping effort, announced a month ago, to shore up nearly all Americans’ protection amid the spread of the highly contagious delta variant.

The nonbinding recommendation — from an influential committee of outside experts who advise the Food and Drug Administration — is not the last word. The FDA will consider the group’s advice and make its own decision, probably within days. And the Centers for Disease Control and Prevention is set to weigh in next week.

In a surprising turn, the advisory panel rejected, 16-2, boosters for almost everyone. Members cited a lack of safety data on extra doses and also raised doubts about the value of mass boosters, rather than ones targeted to specific groups.

Then, in an 18-0 vote, it endorsed extra shots for people 65 and older and those at risk of serious disease. Panel members also agreed that health workers and others who run a high risk of being exposed to the virus on the job should get boosters, too.

That would help salvage part of the White House’s campaign but would still be a huge step back from the far-reaching proposal to offer third shots of both the Pfizer and Moderna vaccines to Americans eight months after they get their second dose.

The White House sought to frame the action as progress.

“Today was an important step forward in providing better protection to Americans from COVID-19,” said White House spokesman Kevin Munoz. “We stand ready to provide booster shots to eligible Americans once the process concludes at the end of next week.”

The CDC has said it is considering boosters for older people, nursing home residents and front-line health care workers, rather than all adults.

The FDA and CDC will most likely decide at some later point whether people who received the Moderna or Johnson & Johnson shots should get boosters.

During several hours of vigorous debate Friday, members of the panel questioned the value of offering boosters to almost everybody 16 and over.

“I don’t think a booster dose is going to significantly contribute to controlling the pandemic,” said Dr. Cody Meissner of Tufts University. “And I think it’s important that the main message we transmit is that we’ve got to get everyone two doses.”

Dr. Amanda Cohn of the CDC said, “At this moment it is clear that the unvaccinated are driving transmission in the United States.”

In a statement, Kathrin U. Jansen, Pfizer head of vaccine research and development, said the company continues to believe that boosters will be a “critical tool in the ongoing effort to control the spread of this virus.”

Scientists inside and outside the government have been divided recently over the need for boosters and who should get them, and the World Health Organization has strongly objected to rich nations giving a third round of shots when poor countries don’t have enough vaccine for their first.

While research suggests immunity levels in those who have been vaccinated wane over time and boosters can reverse that, the Pfizer vaccine is still highly protective against severe illness and death, even amid the delta variant.

The unexpected turn of events could reinforce criticism that the Biden administration got out ahead of the science in its push for boosters. President Joe Biden promised early on that his administration would “follow the science,” in the wake of disclosures of political meddling in the Trump administration’s coronavirus response.

The FDA panel’s overwhelming initial rejection came despite full-throated arguments about the need for boosters from both Pfizer and health officials from Israel, which began offering boosters to its citizens in July.

Sharon Alroy-Preis of Israel’s Ministry of Health said the booster dose improves protection tenfold against infection in people 60 and older.

“It’s like a fresh vaccine,” bringing protection back to original levels and helping Israel “dampen severe cases in the fourth wave,” she said.

Representatives for Pfizer argued that it is important to start shoring up immunity before protection begins to erode. A company study of 44,000 people showed effectiveness against symptomatic COVID-19 was 96% two months after the second dose, but had dropped to 84% by around six months.

Both Pfizer and the Israeli representatives faced pushback from panelists. Several were skeptical about the relevance of Israel’s experience to the U.S. Another concern was whether third doses would exacerbate serious side effects, including rare instances of heart inflammation in younger men.

Pfizer pointed to Israeli data from nearly 3 million boosters to suggest side effect rates would be similar to those already reported.

Dr. Paul Offit, a vaccine expert at Children’s Hospital of Philadelphia, said he was supportive of a third dose for adults over 60 or 65, but “I really have trouble” supporting it for anyone down to age 16.

While an extra shot would probably at least temporarily reduce cases with mild or no symptoms, “the question becomes what will be the impact of that on the arc of the pandemic, which may not be all that much,” Offit said.

Biden’s top health advisers, including the heads of the FDA and CDC, first announced plans for widespread booster shots in mid-August, setting the week of Sept. 20 as an all-but-certain start date. But that was before FDA staff scientists had completed their own assessments of the data.

Earlier this week, two top FDA vaccine reviewers joined a group of international scientists in publishing an editorial rejecting the need for boosters in healthy people. The scientists said studies show the shots are working well.

On Friday, U.S. Surgeon General Dr. Vivek Murthy said the Biden administration announcement was not aimed at pressuring regulators to act but was instead an attempt to be transparent with the public and be prepared in the event that boosters won approval.

“We have always said that this initial plan would be contingent on the FDA and the CDC’s independent evaluation,” Murthy said.

The Biden plan has also raised major ethical concerns about impoverished parts of the world still clamoring for vaccine. But the administration argued that the plan was not an us-or-them choice, noting that the U.S. is supplying large quantities of vaccine to the rest of the globe.

The U.S. has already approved Pfizer and Moderna boosters for certain people with weakened immune systems, such as cancer patients and transplant recipients.

Some Americans, healthy or not, have managed to get boosters, in some cases simply by showing up and asking for a shot. And some health systems already are offering extra doses to high-risk people.

___

The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Department of Science Education. The AP is solely responsible for all content.

Copyright 2021 The Associated Press. All rights reserved.

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'You'll see': Quebec health minister promises bold proposals to solve critical nurse shortage – CTV News Montreal

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QUEBEC CITY —
Quebec Health Minister Christian Dube is promising a plan with bold and original ideas to try to attract thousands of nurses back to the public health network and prevent a breakdown of services.

On Friday, during a scrum with journalists in Lévis, Minister Dube reaffirmed his commitment to doing everything possible to offer nurses a more attractive work environment, different from what they’ve known until now, to convince them to return to the public system.

For years, nurses have complained about the widespread practice of demanding mandatory overtime, which regularly forces them to work exhausting double shifts.

The magnitude of the current crisis, with a shortage of over 4,000 nurses keeping the network from functioning normally, is now pushing the Legault government to pay closer attention to their grievances.

Minister Dube promised to announce new incentives next week, both financial and professional, that he believes will bring back nurses who have opted for early retirement in recent years or who have chosen to practice in the private sector.

He intends to be bold in the way he goes about it, he said.

“You’ll see,” said the minister.

“We’re going to make announcements that might have surprised us a few months or a few years ago, but which will be prompted by the fact that we’ve looked at new ways of doing things with the pandemic.”

While he waits for nurses’ reaction to these soon-to-be-announced short-term incentives, Dube is also planning to implement a more long-term, global reorganization, he said, with “much more structural proposals on the table.”

The day before, the minister had pledged to prevent any service disruptions in the health network, despite the significant shortage of personnel.

He’s also contending with the likelihood the problem will worsen as of October 15, the date by which all health-care staff in Quebec will have to be double vaccinated against COVID-19 to stay on the job.

Those who don’t comply will be suspended without pay for an indefinite period. It’s a scenario that suggests the situation will become even more difficult to manage, as there are an estimated 20,000 unvaccinated employees in the network, at least half of whom provide direct patient care.

This report by The Canadian Press was first published in French on Sept. 17, 2021.

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COVID-19 booster debate in US heads to FDA vaccine advisory committee – National | Globalnews.ca – Global News

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The debate over whether Americans should receive a booster dose of the Pfizer/BioNTech COVID-19 vaccine moves to a panel of independent expert advisers to the U.S. Food and Drug Administration on Friday.

While U.S. health officials, some other countries and vaccine makers have said boosters are needed, many scientists and vaccine experts disagree.

The FDA staff said in documents prepared for the committee this week that the vaccine Pfizer Inc developed with Germany’s BioNTech SE is still very effective at preventing severe illness and death and that the evidence is mixed on whether its efficacy declines over time.


Click to play video: 'COVID-19: Boris Johnson reverses course on vaccine passports for England, announces UK booster program'



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COVID-19: Boris Johnson reverses course on vaccine passports for England, announces UK booster program


COVID-19: Boris Johnson reverses course on vaccine passports for England, announces UK booster program

Pfizer, which is arguing for broad use of a third shot, submitted data from an analysis of over 300 participants in its late stage clinical trial showing that the vaccine’s efficacy diminished by around 6% every two months after the second dose, and that an additional shot boosted immunity.

The FDA’s Vaccines and Related Biological Products Advisory Committee will also consider data from Israel, which has been administering booster doses of the Pfizer/BioNTech vaccine.

It began offering a COVID-19 booster to people as young as age 12 last month, expanding a campaign that began in July for people over 60.

An analysis by Israeli scientists published on Wednesday in the New England Journal of Medicine found that among 1.1 million people age 60 or older who had been fully vaccinated at least 5 months earlier, those who received a booster were less likely to be infected or become severely ill than those who did not get the third shot.

Read more:
Unclear whether U.K.’s booster plan will mean new doses every 6 months, chief says

The Israeli Health Ministry said in documents on Friday that immunity against infection declined during July among all age groups, but particularly among people aged 60 and over who had been vaccinated in January.

Immunity against severe disease dropped in that older group, and such a decline may occur in younger groups aged 50 to 59 as well as 40 to 49, it said. The ministry also said the booster dose did not raise new safety issues.

The booster debate gained urgency as U.S. COVID-19 hospitalizations and deaths surged due to the highly transmissible Delta variant of the virus, mostly among the unvaccinated. But infections among fully vaccinated people have risen and they can spread the virus on occasion, mostly to unvaccinated people.


‘LARGER POPULATIONS MAY TAKE LONGER’

Wall Street analysts see the additional shots ultimately getting approved for a broad population.

“We expect a potential positive FDA support for boosters for elderly ahead of Biden’s rollout, but larger populations may take longer for broad support and approval,” Jefferies analyst Michael Yee said in an email.

Scientists say the strongest evidence for boosters is for older adults and other high risk populations.

“My guess is we are going to end up with a recommendation for booster doses for a certain subpopulation, such as adults older than 65,” said Bill Moss, executive director of the International Vaccine Access Center at the Johns Hopkins Bloomberg School of Public Health.


Click to play video: 'Immunocompromised offered vaccine booster shot. Who is eligible?'



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Immunocompromised offered vaccine booster shot. Who is eligible?


Immunocompromised offered vaccine booster shot. Who is eligible?

More than 1.9 million Americans have already gotten a booster dose after the government authorized them for people with compromised immune systems, according to the U.S. Centers for Disease Control and Prevention (CDC).

The panel will vote on if safety and effectiveness data support approval of a booster at least 6 months after the second dose for people aged 16 and older. The vote is scheduled for between 2:25 pm ET and 4:45 pm ET.

Eight top health officials in the Biden Administration – including the heads of the FDA and the CDC – said in August they believe booster shots will be needed because emerging data shows that protection against COVID-19 decreases over time.

Read more:
Moderna to take on COVID-19, flu with single booster vaccine

The U.S. is planning a booster campaign for the week of Sept. 20, contingent on backing by the FDA and CDC.

Moderna Inc has also asked for approval of a booster and released data on Wednesday showing that protection from its vaccine also wanes over time. That is not expected to be discussed at Friday’s meeting.

(Reporting by Manojna Maddipatla and Ankur Banerjee in Bengaluru; Editing by Caroline Humer and Bill Berkrot)

© 2021 Reuters

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