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Why 'waning immunity' from COVID-19 vaccines isn't as bad as it sounds – CBC.ca

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This is an excerpt from Second Opinion, a weekly roundup of health and medical science news emailed to subscribers every Saturday morning. If you haven’t subscribed yet, you can do that by clicking here.


Canadians concerned over waning immunity from COVID-19 vaccines, breakthrough infections and the need for booster shots in the general public could benefit from a dose of some important context, experts say.

Antibodies, your first line of defence against COVID-19 infection, do decline — and may even be doing so as you’re reading this — but that’s not unexpected.

While one aspect of your vaccine-induced immunity to COVID-19 is technically “waning” in the weeks and months after vaccination, that’s not necessarily a bad thing — because it’s not your immune system’s only form of protection against the virus.

“I don’t even like the term,” said University of Toronto immunologist Jennifer Gommerman. “And the reason I don’t like the term is that it implies that the immune response in its entirety is declining.”

It’s “entirely normal” for antibody levels to drop initially after vaccination and your immune response to the virus to become “contracted” over time, she said. But your body is also creating “highly efficient” memory B cells to fight off COVID-19 long term.

B cells work quickly to generate large quantities of antibodies in the weeks after vaccination, but they typically produce more effective antibodies as time goes on, helping sharpen the long-term response to a virus.

So while reports of waning immunity may sound concerning, that initial decrease in antibody levels may also be necessary in the fight against COVID-19, as it helps fine-tune the immune system’s plan of attack.

A new study published in the journal Science found “robust cellular immune memory” from B cells for at least six months after mRNA vaccination against all circulating strains of the virus — even the highly contagious delta variant.

The researchers found those memory cells, unlike the initial wave of antibodies, continue to learn how to fend off the virus months after vaccination and are actually getting better at it over time.

“That doesn’t sound like ‘waning’ to me,” Gommerman said. “There’s a natural contraction, but waning implies that something bad is happening.” 

While reports of waning immunity may sound concerning, the initial decrease in antibody levels may also be necessary in the fight against COVID-19, as it helps fine-tune the immune system’s plan of attack against the virus. (John Woods/The Canadian Press)

Breakthrough infections don’t tell the whole story

Reports of waning immunity and breakthrough infections have sporadically emerged across Canada in places like the Northwest Territories and New Brunswick, but lack important context and data on who is seriously affected and why.

The N.W.T. has been in the midst of a COVID-19 outbreak since mid-August that started in the Sahtu region before spreading to Yellowknife and its surrounding communities. It has infected 1,584 residents.

During that time, there have been 54 hospitalizations attributed to the outbreak, about 17 of which were among fully vaccinated people. A government spokesperson declined to comment on how many of the nine deaths in the territory were among those fully vaccinated.

WATCH | Concerns over waning immunity leads to expansion of boosters in N.W.T.:

N.W.T. expands COVID-19 boosters over concerns about waning immunity

5 days ago

Northwest Territories Chief Public Health Officer Dr. Kami Kandola talks about the impact of the fourth wave and why the territory is offering COVID-19 booster shots to residents as young as 50. 2:58

In New Brunswick, where reports that one in five COVID-19 deaths occurred in people who were fully vaccinated made headlines this week, the data shows that while 17 fully vaccinated people have died, evidence of widespread waning immunity is lacking.

“New Brunswick has not identified confirmed evidence of waning immunity among COVID-19 cases,” a government spokesperson said in a statement.

In terms of national numbers, 94.7 per cent of all COVID-19 cases in Canada since Dec. 14 have been among those not fully vaccinated, as well as 95.8 per cent of hospitalizations and 94.3 per cent of deaths, according to the Public Health Agency of Canada (PHAC).

That means a total of 520 fully vaccinated Canadians have died of COVID-19 in the nearly 10 months since our vaccine rollout started, compared with 8,520 who were not considered fully vaccinated during that same time period.

“If we have 100 per cent or 95 per cent of the population vaccinated, almost all the cases that we see, including severe cases, will be in vaccinated people — just because most everyone’s vaccinated,” said Dr. Lynora Saxinger, an infectious diseases physician and associate professor at the University of Alberta.

“So that very rare outcome becomes the majority of the outcomes, and seeing an increasing number of cases in vaccinated people over time doesn’t actually mean that the vaccine works less well, necessarily.”

A nurse tends to a patient in the intensive care unit at Scarborough Health Network’s Centenary Hospital in Toronto on Apr. 8. A total of 520 fully vaccinated Canadians have died of COVID-19 in the nearly 10 months since our vaccine rollout started, compared with 8,520 who were not considered fully vaccinated. (Evan Mitsui/CBC)

Underlying conditions key to breakthrough infections 

PHAC says fully vaccinated Canadians who do get COVID-19 are also 79 per cent less likely to be hospitalized and 64 per cent less likely to die, backing up new Canadian data showing strong vaccine protection from infection, hospitalization and death.

But key information on the age, underlying health conditions or specific vaccine combination administered to those who were hospitalized or died from COVID-19 two weeks after their second shot is not available in Canada due to health privacy laws.

The recent death of former U.S. Secretary of State Colin Powell from COVID-19 sparked fresh debate about breakthrough infections and waning immunity. But less attention was paid to the fact he was at heightened risk due to a blood cancer called multiple myeloma.

Older, frailer Canadians living with comorbidities in congregate settings, such as long-term care facilities, are at increased risk of breakthrough infections because their antibody levels drop “much faster” than in the general population, said Gommerman.

A recent preprint study from the Toronto-based Lunenfeld-Tanenbaum Research Institute at Sinai Health analyzed 119 Ontario long-term care residents and 78 staff over four months, finding much lower levels of neutralizing antibodies in the elderly patients.

Gommerman also stresses there’s an important difference between infections and disease. 

“We expect people to get infected — even healthy people to get infected — as antibody levels decline, because the only thing that can protect you against a breakthrough infection are antibodies,” she said.

“But we have to think about who we’re looking at, and what underlying comorbidities might be there in people who experienced breakthrough disease.”

Other immunocompromised groups, such as transplant patients, have shown declining protection from COVID-19 vaccines, as evidenced in the New England Journal of Medicine from researchers at the University Health Network (UHN) in Toronto. 

WATCH | NACI recommends COVID-19 booster shots for long-term care residents:

NACI recommends COVID-19 booster shots for seniors in long-term care

24 days ago

Amid a global debate over COVID-19 vaccine boosters, the National Advisory Committee on Immunization is recommending third doses for Canada’s most vulnerable, especially seniors in long-term care homes. 1:58

“If you are a healthy person and you’ve been fully vaccinated, you don’t need to worry about getting severe COVID-19,” Gommerman said. 

“If you are worried about getting infected with SARS-CoV-2, you should worry because you have people around you who are not vaccinated or who are under-immune.” 

Boosters for general population ‘premature’ in Canada

New data from researchers at the Institute for Clinical Evaluative Sciences (ICES) in Toronto, which has not yet been peer-reviewed, found fully vaccinated people over 16 in Ontario were highly protected against both infection and severe COVID-19 after eight months.

ICES’s vaccine estimates, which have not yet been published, show that protection against symptomatic infection does drop — from 94 per cent to 81 per cent — but protection against severe outcomes remained high, at more than 90 per cent.

“The main takeaway is that we don’t need to do boosters at this time for the general population. We can hold off and wait and see — and when we start seeing the waning, then that’s when we should use the boosters,” said Dr. Jeff Kwong, an epidemiologist and senior scientist at ICES.

“It would be premature to do it at this time and not in our best interest, because we’re allowing other variants to emerge potentially if we let the pandemic spread uncontrolled in other parts of the world [where] they’re not vaccinated.”

WATCH | PHAC reviewing data supporting COVID booster shots in Canada:

Public Health officials say they are reviewing the data supporting COVID booster shots

8 days ago

Chief Public Health Officer Dr. Theresa Tam says Canada’s Public Health Agency is reviewing the data supporting third doses of a COVID vaccine and will issue recommendations soon. 1:23

Saxinger said the vast majority of Canadians who get severely ill or hospitalized after full vaccination are the very elderly, the immunocompromised, transplant patients and people with certain types of cancers. 

“That group of people, of course, they should get a third dose,” she said. “But even with a third dose, they still are going to remain vulnerable as long as we have circulating virus in the community.”

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Study suggests Pfizer COVID-19 vaccine only partially protects against Omicron – Toronto Sun

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The Omicron variant can partially evade protection from two doses of Pfizer and partner BioNTech’s COVID-19 vaccine, the research head of a laboratory at the Africa Health Research Institute in South Africa said on Tuesday.

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But the study showed that blood from people who had received two doses of the vaccine and had a prior infection was mostly able to neutralize the variant, suggesting that booster doses of the vaccine could help to fend off infection.

The Omicron variant, first detected in southern Africa last month, has triggered alarms globally of another surge in infections, with more than two dozen countries from Japan to the United States reporting cases.

The World Health Organization classified it on Nov. 26 as a “variant of concern,” but said there was no evidence to support the need for new vaccines specifically designed to tackle the Omicron variant with its many mutations.

Alex Sigal, a professor at the research institute, said on Twitter there was “a very large drop” in neutralization of the Omicron variant relative to an earlier strain of COVID-19.

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A separate lab test by virologist Sandra Ciesek of the University Hospital Frankfurt painted a somewhat bleaker picture.

Exposing the blood of vaccinated individuals to different virus variants, she found that the ability to mount an antibody response to Omicron in people who had three shots of BioNTech/Pfizer was up to 37 times lower than the response to Delta.

An antibody response to Omicron half a year after a two-shot regimen of Pfizer/BioNTech, Moderna or a mixed course of AstraZeneca/BioNTech was not even measurable, Ciesek added.

She posted only selected findings on Twitter, not including the number of samples, and the university said the paper had not yet been published.

“The set of data underscores that it makes sense to develop a vaccine that is adapted to Omicron,” Chiesek tweeted, adding that no conclusion could be drawn about protection against severe disease.

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WHO’s chief scientist, Soumya Swaminathan, said a large drop in the antibody response of vaccinated people to Omicron had been expected.

“This does not mean the vaccine will not work – T-cell immunity (is) likely to persist,” she said on Twitter, referring to a cellular immune response that is believed to prevent severe disease as a second line of immune defence.

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Researchers including Carsten Watzl of the German Society of Immunology and Penny Ward, visiting professor at King’s College London, said the findings underscored the need to get booster shots because a three-shot course would likely continue to protect against severe disease.

We apologize, but this video has failed to load.

Sigal’s lab tested blood from 12 people who had been vaccinated with two doses of the Pfizer/BioNTech vaccine, according to a manuscript posted on the website for his lab. The preliminary data in the manuscript has not yet been peer reviewed.

Blood from five out of six people who had been vaccinated as well as previously infected with COVID-19 still neutralized the Omicron variant, the manuscript said.

“These results are better than I expected. The more antibodies you got, the more chance you’ll be protected from Omicron,” Sigal said on Twitter.

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He said the lab had not tested the variant against blood from people who had received a booster dose, because they are not available in South Africa yet.

According to the manuscript, the lab observed a 41-fold decline in levels of neutralizing antibodies against the Omicron variant.

Sigal said on Twitter that figure is likely to be adjusted after his lab does more experiments.

While neutralizing antibodies are an indicator of the body’s immune response, scientists believe other kinds of cells such as B-cells and T-cells are also stimulated by the vaccines and help protect against the effects of the coronavirus.

The preliminary data does not indicate that the vaccine is less able to prevent severe illness or death. While lab tests are under way, BioNTech CEO Ugur Sahin said last week “we think it’s likely that people will have substantial protection against severe disease caused by Omicron.”

There is not significant data yet on how vaccines from Moderna, Johnson & Johnson and other drugmakers hold up against the new variant. All the manufacturers, including Pfizer and BioNTech, are expected to release their own data within weeks.

BioNTech’s Sahin told NBC News on Tuesday that the drugmaker has data coming on Wednesday or Thursday.

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Seven Omicron variant cases in Simcoe County linked to travellers from Nigeria – BayToday.ca

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The Simcoe Muskoka District Health Unit says it is investigating a household cluster in Simcoe County with seven confirmed COVID-19 cases that have a strong probability of being the Omicron variant of concern. All the cases are currently isolating at home.

“The cluster is linked to travellers who arrived in Simcoe County from Nigeria in late November,” says a news release.

The Simcoe Muskoka Health Unit borders the North Bay Parry Sound District Health Unit to the immediate south.

“Although the health unit is awaiting whole genomic sequencing of the samples which should be available in the next 7 to 14 days, given the travel history and the preliminary laboratory screening results, the likelihood of an Omicron cluster is very high.”

The Unit’s case and contact management team is currently following up with each case to identify close contacts regarding isolation and testing.

“Scientific data about the Omicron variant is still emerging,” said Dr. Charles Gardner, Medical Officer of Health. “Early evidence suggests that the variant might be more transmissible. While we continue to closely monitor this local situation, I urge all residents to remain vigilant about following public health measures, to monitor themselves for symptoms of COVID-19 and seek testing immediately if any should develop, and get vaccinated if they have not already done so.”

The rate of COVID-19 infection among the unvaccinated vaccine-eligible Simcoe Muskoka population is seven times higher than it is for the fully vaccinated population and the rate of COVID-19 hospitalizations is 15 times higher says Gardner. Getting the vaccine can lower the risk of serious illness, hospitalization, and death.

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Eating disorder symptoms and self-harm linked to higher levels of depression and anxiety during COVID-19 pandemic – Medical Xpress

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Timeline of ALSPAC assessments. NEET Not in education, employment or training. Gray text indicates the name of the ALSPAC questionnaire. Credit: DOI: 10.1186/s40337-021-00510-9

Young adults with previous self-harm or eating disorders reported higher levels of depression and anxiety during the pandemic, even when restrictions had eased, according to new research.

The study, led by the University of Bristol and funded by Elizabeth Blackwell Institute, Medical Research Council and Medical Research Foundation, has been published in the Journal of Eating Disorders. It looked at questionnaire information for 2,657 individuals from world-renowned health study Children of the 90s (also known as the Avon Longitudinal Study of Parents and Children) before and during the COVID-19 pandemic.

Researchers analyzed the relationship between previous reports of eating disorder symptoms and before the pandemic, and (symptoms of depression and anxiety) and mental wellbeing during the COVID-19 pandemic. The study also assessed whether , such as more sleep, relaxation techniques, or visiting green space, could be linked to and wellbeing in young adults with and without previous eating disorder symptoms or self-harm.

Researchers studied questionnaire data from 2017, when the participants were then aged 25 years, as well as data taken during the pandemic in 2020.

At age 25, 32 percent of the 2,657 young adults reported at least one eating disorder , 9 percent reported self-harm, and 5.5 percent reported both an eating disorder symptom and self-harm in the last year.

During the pandemic, those with previously reported eating disorder symptoms and/or self-harm had more symptoms of depression and anxiety, and worse mental wellbeing, compared to individuals without previous symptoms. This remained the case after adjusting for their pre-pandemic levels of depression, anxiety and mental wellbeing.

Lifestyle changes appeared to have little effect on the increased risk for mental health problems in those with prior eating disorder symptoms or self-harm.

Lead author Dr. Naomi Warne, Senior Research Associate at the University’s Centre for Academic Mental Health, said: “Eating and self-harm are common and troubling mental health problems among . In the UK, approximately 1.25 million people are living with an eating disorder and almost 1 in 15 adults report self-harm.

“Our research has highlighted individuals with prior self-harm and eating disorder symptoms are key risk groups and further longitudinal research is needed to understand their ongoing mental health as well as risk and protective factors.

“Individuals with previous eating disorder symptoms and self-harm should be considered vulnerable to depression and anxiety throughout the pandemic and beyond. Funding for rapid and responsive service provision is essential to reduce the impact of the on those with mental health problems.”


Explore further

One in four adults with depression or anxiety lacked mental health support during pandemic


More information:
Naomi Warne et al, Disordered eating and self-harm as risk factors for poorer mental health during the COVID-19 pandemic: a UK-based birth cohort study, Journal of Eating Disorders (2021). DOI: 10.1186/s40337-021-00510-9

Citation:
Eating disorder symptoms and self-harm linked to higher levels of depression and anxiety during COVID-19 pandemic (2021, December 8)
retrieved 8 December 2021
from https://medicalxpress.com/news/2021-12-disorder-symptoms-self-harm-linked-higher.html

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