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'Waning immunity?': Experts say term leads to false understanding of COVID-19 vaccines – CHEK

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The idea of waning immunity has picked up steam in recent weeks, with some countries using it to justify rolling out third-dose COVID-19 vaccine boosters to their populations.

But immunologists say the concept has been largely misunderstood.

While antibodies — proteins created after infection or vaccination that help prevent future invasions from the pathogen — do level off over time, experts say that’s supposed to happen.

And it doesn’t mean we’re not protected against COVID-19.

Jennifer Gommerman, an immunologist with the University of Toronto, said the term “waning immunity” has given people a false understanding of how the immune system works.

“Waning has this connotation that something’s wrong and there isn’t,” she said. “It’s very normal for the immune system to mount a response where a ton of antibodies are made and lots of immune cells expand. And for the moment, that kind of takes over.

“But it has to contract, otherwise you wouldn’t have room for subsequent immune responses.”

Antibody levels ramp up in the “primary response” phase after vaccination or infection, “when your immune system is charged up and ready to attack,” said Steven Kerfoot, an associate professor of immunology at Western University.

They then decrease from that “emergency phase,” he added. But the memory of the pathogen and the body’s ability to respond to it remains.

Kerfoot said B-cells, which make the antibodies, and T-cells, which limit the virus’s ability to cause serious damage, continue to work together to stave off severe disease long after a vaccine is administered. While T-cells can’t recognize the virus directly, they determine which cells are infected and kill them off quickly.

Recent studies have suggested the T-cell response is still robust several months following a COVID-19 vaccination.

“You might get a minor infection … (but) all of those cells are still there, which is why we’re still seeing very stable effectiveness when it comes to preventing severe disease,” Kerfoot said.

A pre-print study released this week by Public Health England suggested protection against hospitalization and death remains much higher than protection against infection, even among older adults.

So the concept of waning immunity depends on whether you’re measuring protection against infection or against severe disease, Kerfoot said.

Ontario reported 43 hospitalized breakthrough cases among the fully vaccinated on Friday, compared to 256 unvaccinated hospitalized infections. There were 795 total new cases in the province that day, 582 among those who weren’t fully vaccinated or had an unknown vaccination status.

British Columbia, meanwhile, saw 53 fully vaccinated COVID-19 patients hospitalized over the last two weeks, compared to 318 unvaccinated patients.

“You’ll hear people say that vaccines aren’t designed to protect infection, they’re designed to prevent severe disease,” Kerfoot said. “I wouldn’t say necessarily it’s the vaccine that’s designed to do one or another … that’s just how the immune system works.”

Moderna released real-world data this week suggesting its vaccine was 96 per cent effective at preventing hospitalization, even amidst the more transmissible Delta variant, and 87 per cent effective at preventing infection — down from the 94 per cent efficacy seen in the clinical trials last year.

Moderna CEO Stephane Bancel said that dip “illustrates the impact of waning immunity and supports the need for a booster to maintain high levels of protection.”

Pfizer-BioNTech has argued the same with its own data, and an advisory panel to the U.S.-based Food and Drug Administration voted Friday to endorse third doses for those aged 65 and older, or at high risk for severe disease.

However, the panel rejected boosters for the general population, saying the pharmaceutical company had provided little safety data on extra jabs.

Gommerman said the efficacy data presented by Moderna doesn’t signal the need for a third dose.

“The fact it protects 87 per cent against infection, that’s incredible,” she said. “Most vaccines can’t achieve that.”

Bancel said Moderna’s research, which has yet to be peer reviewed, suggested a booster dose could also extend the duration of the immune response by reupping neutralizing antibody levels.

But Dr. Sumon Chakrabarti, an infectious physician in Mississauga, Ont., said looking solely at the antibody response is misleading, and could be falsely used as justification for an infinite number of boosters.

Israel, which has opened third doses for its citizens, recently talked about administering fourth doses in the near future.

“This idea of waning immunity is being exploited and it’s really concerning to see,” Chakrabarti said. “There’s this idea that antibodies mean immunity, and that’s true … but the background level of immunity, the durable T-cell stuff, hasn’t been stressed enough.”

While some experts maintain boosters for the general population are premature, they agree some individuals would benefit from a third jab.

The National Advisory Committee on Immunization has recommended boosters for the immunocompromised, who don’t mount a robust immune response from a two-dose series.

Other experts have argued residents of long-term care, who were prioritized when the rollout began last December, may also soon need a third dose. The English study suggests immunity could be waning in older groups but not much — if at all — among those under age 65.

Chakrabarti said a decrease in protection among older populations could be due more to “overlapping factors,” including their generally weaker immune systems and congregate-living situations for those in long-term care.

“These are people at the highest risk of hospitalization,” he said. “Could (the length of time that’s passed following their doses) be playing a role? Yeah, maybe.”

While we still don’t know the duration of the immune response to COVID-19 vaccination, Gommerman said immune cells typically continue to live within bone marrow and make small amounts of antibodies for “decades.”

“And they can be quickly mobilized if they encounter a pathogen,” she said.

Melissa Couto Zuber/The Canadian Press

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Beck: Feeling bloated? Try these diet tweaks – The Globe and Mail

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Many of us have experienced bloating at one time or another, the sensation when your stomach feels full and swollen. For some people, though, the discomfort caused by chronic bloating can interfere with everyday life.

Bloating is common affecting up to 30 per cent of the general population. Among people with irritable bowel syndrome (IBS), more than 90 per cent report bloating.

The good news: In many cases making simple diet changes can reduce, even resolve, uncomfortable bloating. The key, however, is determining what your bloat triggers are.

What is bloating?

Bloating is a recurrent sense of fullness, pressure or trapped gas in the upper abdomen (e.g., the stomach area). In some cases it’s accompanied by abdominal distention, a measurable increase in abdominal girth. Abdominal pain, gas and burping can also be present.

Symptoms may worsen over the course of the day or they can be triggered by eating a meal. Often bloating dissipates overnight.

The most common cause of bloating is air, or gas, trapped in the intestinal tract. What you eat – and how you eat – can lead to a build-up of intestinal gas.

Other reasons for bloating include inflammatory bowel disease, small intestinal bacterial overgrowth (SIBO), gluten intolerance (celiac disease) and non-celiac gluten-sensitivity. Chronic constipation, stress and certain medications (e.g., Aspirin, antacids, anti-diarrhea drugs) can also contribute to bloating.

Diet strategies to prevent bloating

While bloating may be caused by an underlying medical condition, it’s most often a result of what you eat and/or how you eat. Your first line of defense is addressing your diet.

Avoid overeating. Eating large meals, especially fatty meals that empty from your stomach slowly, can make you feel bloated. To eat smaller portions, serve meals on a luncheon-sized plate (seven to nine inches in diameter) instead of a dinner plate.

Check in with your hunger level halfway through your meal. You’ve had enough to eat when you feel satisfied but not full.

Slow your eating pace. Eating quickly can contribute to bloating by causing you to overeat. It takes roughly 20 minutes for appetite-related hormones to kick in and tell your brain you’ve had enough to eat.

Eating too fast also increases the amount of air you swallow, which can cause bloating. To eat slowly, put down your knife and fork after every bite and chew thoroughly.

Chewing gum, sucking on hard candies and drinking from a straw also increase the amount of air you swallow.

Increase fibre, water. If constipation is causing your bloating, increase your intake of foods rich in insoluble fibre, the type of fibre that retains water and adds bulk to stool, helping it pass more quickly through the colon.

Wheat bran, 100-per-cent bran cereal, whole wheat pasta and whole grain rye bread are excellent sources of insoluble fibre. Apples, berries, kiwifruit, pinto beans, green peas, sweet potato, avocado and prunes are also decent sources.

Fibre needs to absorb water to work effectively. Drink nine cups (women) and 12 cups (men) of water each day.

Try lactose-free. If you’re intolerant to lactose, the natural sugar in cow’s milk, consuming more lactose than your small intestine can digest can cause bloating, abdominal pain, distention, gas and loose stools.

If you suspect lactose may be the culprit, switch to lactose-free milk and lactose-free yogurt to see if your bloating symptoms improve. Hard cheeses (e.g., cheddar, Swiss, Parmesan) are low in lactose.

Consider a low-FODMAP diet. If you have IBS, bloating may be triggered by a group of poorly absorbed carbohydrates called FODMAPs. (FODMAP stands for fermentable, oligosaccharides, disaccharides, monosaccharides and polyols.) Lactose, by the way, is a FODMAP.

As FODMAPs move through the small intestine they draw in water. Once in the large intestine, gut bacteria ferment FODMAPs, which produces gas. Extra water and gas in the intestinal tract can cause IBS symptoms such as bloating, abdominal pain, flatulence and diarrhea.

Finding out which FODMAPs you’re sensitive to involves eliminating high-FODMAP foods for a short period of time and then, one at a time, adding FODMAPs back to your diet.

Consult a dietitian knowledgeable in low-FODMAP meal planning – and the strategic reintroduction and testing of FODMAPs – to ensure you follow a nutritionally balanced diet.

When to see a doctor

If dietary modifications don’t reduce your bloating, consult your doctor. It’s important to rule out any other conditions that could be causing your symptoms.

Leslie Beck, a Toronto-based private practice dietitian, is director of food and nutrition at Medcan. Follow her on Twitter @LeslieBeckRD

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Two doctors barred from issuing medical exemptions for COVID-19 vaccines, mandatory mask requirements – CP24 Toronto's Breaking News

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The regulatory body for Ontario’s medical profession has barred two outspoken doctors from issuing any medical exemptions related to COVID-19 vaccinations.

The College of Physicians and Surgeons of Ontario announced the restrictions against Dr. Mark Trozzi, of Harrow, and Dr. Rochagne Kilian, of Owen Sound, on Monday morning.

Both Trozzi and Kilian have been outspoken about COVID-19 restrictions in the past while expressing skepticism about COVID-19 vaccines.

Kilian, in particular, has previously been a speaker at several rallies organized by the group “Grey- Bruce Freedom Fighters” and last month resigned from her position as an emergency room doctor in protest over the Grey Bruce Health Services handling of the pandemic.

Under the interim order announced today but issued last week, the physicians have been barred from providing medical exemptions in relation to COVID-19 vaccines, mandatory mask requirements for COVID-19 and testing for COVID-19.

Their practices will also be required to post information about restrictions in their offices.

The college said that it is issuing the interim orders under powers granted to it in 2018, which permits it to “suspend or impose terms, conditions or limitations on a member’s certificate of registration where the college believes that the conduct exposes or is likely to expose patients to harm or injury.

Neither doctor has been referred to the tribunal with allegations related to the restrictions at this point.

Asked about the orders at Queen’s Park on Monday, NDP Leader Andrea Horwath applauded the college for “proactively” addressing the issue while suggesting that there should be more of a system to protect the integrity of Ontario’s proof-of-vaccination requirement.

“If this has happened with these two physicians, where’s the system to make sure it’s not happening in many other instances so that how can we be assured of the reliability?” she asked. “We know that (Doug) Ford didn’t want to do this, we know that he got dragged to a certificate program kicking and screaming and a result it was late, and it’s inadequate and this is another one of the inadequacies.”

Chief Medical Officer of Health Dr. Kieran Moore has previously said that COVID-19 vaccines are safe and highly effective and that medical exemptions should only be granted at a rate of about five people per 100,000.

He has said that the only two legitimate medical exemptions are an allergy to one of the components of the vaccine or an increased risk of myocarditis.

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Biden administration asks U.S. Supreme Court to block Texas abortion law

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President Joe Biden’s administration on Monday asked the U.S. Supreme Court to block a Texas law that imposes a near-total ban on  abortion after a lower court reinstated the Republican-backed measure.

The administration made its request to the Supreme Court seeking to quickly reverse a decision by the New Orleans-based 5th U.S. Circuit Court of Appeals to lift a judge’s order blocking the law while litigation over the matter continues.

 

(Reporting by Andrew Chung in New York and Lawrence Hurley in Washington; Editing by Will Dunham)

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