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Why an Omicron infection alone might not offer the immune boost you'd expect – Yahoo News Canada



Though millions have survived Omicron infections in the last month, emerging evidence suggests high infection rates won’t necessarily translate into widespread protection against re-infections — unless you’re layering exposure onto the broader immunity provided by vaccines. (Justin Tallis/AFP/Getty Images – image credit)

In the span of just weeks, millions of Canadians became infected with SARS-CoV-2. Globally, more cases were reported in the first 10 weeks after the Omicron variant was identified than in all of 2020.

It was a mass infection event quite unlike anything we’d seen in the pandemic to date, hitting both the unvaccinated and vaccinated — but not in the same way.

While vaccinated and boosted individuals largely avoid dire outcomes from COVID-19, data continues to show that unvaccinated individuals remain at a far higher risk of serious illness, hospitalization, and death.

Emerging evidence also suggests high infection rates won’t necessarily translate into widespread protection against re-infections down the line — unless you’re layering Omicron exposure onto the broader immunity provided by vaccines.

“In people who are not vaccinated, they’re not making a good response to Omicron,” said immunologist and University of Toronto professor Jennifer Gommerman.

“It’s very different than for people who are fully vaccinated against SARS-CoV-2; those people seem to make a good response to Omicron, which is good news.”

‘Wimpy’ immunity signal from just Omicron in lab

It’s clear leading vaccines, designed to combat the original SARS-CoV-2 strain, struggle more against this latest variant. Its constellation of mutations — dozens of them, including many in the virus’s spike protein — allow it to break through that immunity, though two vaccine doses still cut your chance of getting seriously ill.

Boosters, meanwhile, seem to ramp up the level of protection even more, both studies and government data show.

A study shared online in January, which isn’t yet published or peer-reviewed, offered an early look at where Omicron fits into the ever-evolving immunity puzzle that scientists have been striving to piece together since SARS-CoV-2 first burst into global consciousness in early 2020.

Was there, perhaps, an upside to such widespread Omicron infection at once?

“The question that everybody raised is … is that really going to lead to immunity — herd immunity, mass immunity — so that we, at least for a while, are safe from other variants?” said researcher Melanie Ott, director of the Gladstone Institute of Virology and a professor of medicine at the University of California San Francisco.

In hopes of finding an answer, Ott and other researchers exposed lab mice to different variants and found being infected with the previously-dominant Delta variant induced broad immunity against both Delta and Omicron. Catching Omicron, the team found, didn’t have the same effect, only shielding mice from an Omicron reinfection.

HKUMed and Electron Microscope Unit/HKUHKUMed and Electron Microscope Unit/HKU

HKUMed and Electron Microscope Unit/HKU

Gommerman, who was not affiliated with the study, said the use of mice offered the researchers a blank slate, assuring the subjects didn’t have previous exposure to this virus, but was also a key limitation — more research is needed to confirm the early findings in humans.

The team did also analyze human samples from Omicron and Delta breakthrough cases in vaccinated individuals, and in this case, both variants appeared to offer an immune boost to protect against getting reinfected with the other.

Together, the results indicate that having an Omicron infection “enhances pre-existing immunity elicited by vaccines,” but might not induce broad immunity in unvaccinated individuals, the researchers wrote.

In an interview with CBC News, Ott put it this way: “In the unvaccinated people, I think this response is very narrow and limited, and might not have the anticipated result of broad herd immunity for protection against future variants.”

Vaccines, meanwhile, offer a “fantastic background for immunity to build up if you have a breakthrough infection,” she added.

Gommerman agreed the results signal there’s likely a “wimpy immune response” post-Omicron in people who get infected without previously being vaccinated.

“People who are unvaccinated and got Omicron might think they’re good to go,” she said. “And that’s likely not the case based on this preprint.”

WATCH | COVID-19 deaths, hospitalizations hit record highs:

Immunity like building up an army

The apparent differences in how our bodies tackle this evolving virus, depending on whether the exposures happen post-vaccination or without that extra protection, aligns with the basic science behind how vaccines work.

When your body first encounters a virus or a vaccine, vaccine researcher Alyson Kelvin explains, your immune system builds up an army to attack different parts of that threat.

“If you see the same virus or vaccine again, then you go back to that same army — and you pick out the strongest members of that army,” she continued. “If you encounter a completely different virus or vaccine, then you will no longer go back and recall that old army. You’ll have to make a new one.”

As this virus keeps evolving, that could mean a need for more fresh armies, building up and broadening our immune system’s defence network one infection at a time.

Kelvin, who works at the University of Saskatchewan’s Vaccine and Infectious Disease Organization, is among those hopeful that through a combination of vaccination and infections, that population-level immunity will continue to rise, while instances of severe disease continue to drop.

“That’s an optimistic point of view,” she admitted. “But we can always have a brand new, antigenically-different coronavirus that might change all that, and we’re not able to lean back on our pre-existing immunity.”

WATCH | Pfizer testing Omicron-based vaccine:

The weeks and months ahead will provide researchers with a better sense of how robust and long-lasting post-Omicron immunity may be, and how it differs between the vaccinated and unvaccinated.

There’s also ongoing research to adapt existing Pfizer-BioNTech and Moderna vaccines to this variant, while other global teams are exploring universal coronavirus vaccines that could tackle any future variants, or intranasal options which may prevent more mild, breakthrough infections from happening in the first place.

All those efforts offer hope that regardless of how our bodies handle infections, vaccines will continue providing a way out of this pandemic — but that requires people actually getting the shots.

“We got kind of lucky with Omicron in that it causes more mild illness, but there’s no guarantee that a subsequent variant will likewise be mild,” Gommerman said.

“So for those Canadians who have yet to be vaccinated, if they’ve had Omicron, that shouldn’t stop them; they should still go out and get the vaccine.”

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COVID-19 vaccines saved 20M lives in 1st year, scientists say – CTV News



Nearly 20 million lives were saved by COVID-19 vaccines during their first year, but even more deaths could have been prevented if international targets for the shots had been reached, researchers reported Thursday.

On Dec. 8, 2020, a retired shop clerk in England received the first shot in what would become a global vaccination campaign. Over the next 12 months, more than 4.3 billion people around the world lined up for the vaccines.

The effort, though marred by persisting inequities, prevented deaths on an unimaginable scale, said Oliver Watson of Imperial College London, who led the new modelling study.

“Catastrophic would be the first word that comes to mind,” Watson said of the outcome if vaccines hadn’t been available to fight the coronavirus. The findings “quantify just how much worse the pandemic could have been if we did not have these vaccines.”

The researchers used data from 185 countries to estimate that vaccines prevented 4.2 million COVID-19 deaths in India, 1.9 million in the United States, 1 million in Brazil, 631,000 in France and 507,000 in the United Kingdom.

An additional 600,000 deaths would have been prevented if the World Health Organization target of 40% vaccination coverage by the end of 2021 had been met, according to the study published Thursday in the journal Lancet Infectious Diseases.

The main finding — 19.8 million COVID-19 deaths were prevented — is based on estimates of how many more deaths than usual occurred during the time period. Using only reported COVID-19 deaths, the same model yielded 14.4 million deaths averted by vaccines.

The London scientists excluded China because of uncertainty around the pandemic’s effect on deaths there and its huge population.

The study has other limitations. The researchers did not include how the virus might have mutated differently in the absence of vaccines. And they did not factor in how lockdowns or mask wearing might have changed if vaccines weren’t available.

Another modelling group used a different approach to estimate that 16.3 million COVID-19 deaths were averted by vaccines. That work, by the Institute for Health Metrics and Evaluation in Seattle, has not been published.

In the real world, people wear masks more often when cases are surging, said the institute’s Ali Mokdad, and 2021’s Delta wave without vaccines would have prompted a major policy response.

“We may disagree on the number as scientists, but we all agree that COVID vaccines saved lots of lives,” Mokdad said.

The findings underscore both the achievements and the shortcomings of the vaccination campaign, said Adam Finn of Bristol Medical School in England, who like Mokdad was not involved in the study.

“Although we did pretty well this time — we saved millions and millions of lives — we could have done better and we should do better in the future,” Finn said.

Funding came from several groups including the WHO; the U.K. Medical Research Council; Gavi, the Vaccine Alliance; and the Bill and Melinda Gates Foundation.


AP health and science reporter Havovi Todd contributed


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


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ACIP Backs Moderna's COVID Shot for Kids 6-17 Years – Medpage Today



The CDC’s Advisory Committee on Immunization Practices (ACIP) voted unanimously on Thursday to recommend that children ages 6-17 years receive Moderna’s COVID-19 vaccine.

With a 15-0 vote, ACIP endorsed a two-dose primary series of the mRNA vaccine for kids ages 6-11 years (50 mcg per dose) and adolescents ages 12-17 (100 mcg per dose). The recommendation now awaits approval from CDC Director Rochelle Walensky, MD, MPH.

The recommendation was largely expected, and followed FDA’s emergency use authorization last week. Until then, only Pfizer/BioNTech’s mRNA vaccine had been authorized and recommended for these age groups.

At Thursday’s meeting, ACIP members considered safety and efficacy data on Moderna’s vaccine, which was primarily studied during periods where the ancestral SARS-CoV-2 and Delta strains were predominant, in teens and the younger kids, respectively. In both groups, the vaccine was effective against severe disease and hospitalization.

“We know that the benefits outweigh the risks for mRNA COVID-19 vaccine in all ages,” said Sara Oliver, MD, of the CDC’s National Center for Immunization and Respiratory Diseases, during the meeting. “Receipt of this primary series continues to be the safest way to prevent serious COVID-19.”

Oliver emphasized that serious outcomes with COVID-19 do not spare kids. The Omicron wave was accompanied by a surge in hospitalizations among children, and she pointed to 189 COVID-related deaths in kids 5-11 years and 443 in kids 12-17 throughout the course of the pandemic.

Several ACIP members raised questions about the intervals between the first and second dose of the Moderna vaccine, as such an approach may reduce the risk of myocarditis associated with the vaccine. Some evidence suggests the Moderna vaccine carries a higher risk of myocarditis or pericarditis than Pfizer’s vaccine, though CDC experts cautioned that these findings are not consistent in all U.S. monitoring systems.

Among close to 55 million doses of Pfizer’s vaccine administered to individuals ages 5-17 years, the rare adverse event has been observed in at least 635 children, according to the CDC. Risk is typically higher among children ages 12-17, in boys, and after the second dose. Among kids age 5-11, there were no signals detected.

In a presentation on clinical considerations, Elisha Hall, PhD, of the CDC’s National Center for Immunization and Respiratory Diseases, said that although the current recommendation is for a 4-week gap between the first and second doses, the CDC will likely be recommending an 8-week interval for adolescent males. (The CDC also recommends shorter dose intervals for children who are immunocompromised.)

Some of the ACIP members expressed confusion about the product labels on Moderna’s vaccines in each age group. The product authorized for kids 6-11 will have the same color cap as the vaccine for children ages 6 months to 5 years, but a different color border to distinguish the higher concentration. For the product authorized for kids ages 12-17, it will have the same label as the adult vaccine, as it is the same dose.

“I am … concerned about vaccine administration errors,” said Matthew Daley, MD, chair of ACIP’s working group. Others echoed concerns about administration blunders, encouraging more resources for providers and further clarification on labeling from the manufacturer.

Safety and efficacy data for Moderna’s vaccine in this younger population came from two ongoing phase II/III clinical trials (study mRNA-1273-P203 for adolescents ages 12-17 and study mRNA-1273-P204 for kids ages 6-11 years). The studies included nearly 8,000 kids in total.

Among participants ages 12-17, vaccine efficacy was 93.3% (95% CI 47.9-99.9) during a time when the ancestral and Alpha strains were predominant. Among the younger group, vaccine efficacy was 76.8% (95% CI -37.3 to 96.6) during a period when Delta was most prevalent.

The committee agreed on the data that COVID-19 vaccines protect children against severe disease. Many children in this age group, however, remain unvaccinated. Approximately 30% of teens and 65% of younger kids have yet to receive a vaccine, according to Oliver.

“We can predict with future COVID-19 surges, the unvaccinated will continue to bear the burden of disease,” she said.

  • Amanda D’Ambrosio is a reporter on MedPage Today’s enterprise & investigative team. She covers obstetrics-gynecology and other clinical news, and writes features about the U.S. healthcare system. Follow

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COVID Rates Dropping; Vaccination Campaign Continues –



Health officials in Canada are warning of a seventh wave of COVID-19 this fall, with a possible new variant.

Dr. Kit Young Hoon is the Medical Officer of Health for the Northwestern Health Unit and stresses they will be ready.

“Although the timing of an increase in COVID-19 specifically is difficult to predict, the Northwestern Health Unit will be prepared to offer large-scale COVID-19 vaccinations in the fall to protect our communities most vulnerable.”

She notes the vaccine remains the best way to stay protected and vaccines continue to be offered for those eligible.

The Health Unit is reporting 132 COVID cases confirmed through PCR testing.

One hundred of them are in communities under the jurisdiction of the Sioux Lookout First Nations Health Authority.

Medical Officer of Health Dr. Kit Young Hoon says numbers are lower elsewhere.

“Overall, there’s been a steady decrease in hospitalizations due to COVID-19 locally. Case numbers in most health hubs are low, as are our institutional outbreak numbers”.

The positivity rate is sitting at 11.2%.

Case count (Health Hubs):

-Sioux Lookout (on reserve): 100
-Kenora: 15
-Sioux Lookout: (off reserve): 5
-Dryden: 4
-Red Lake: 3
-Fort Frances: 3
-Atikokan: 2

There are 3 institutional COVID outbreaks in the region.

That includes one at the Pinecrest home for the aged in Kenora.

Recent testing showed 25 residents testing positive for the virus.

Day and overnight absences have been placed on hold for the time being, but one essential caregiver is allowed for each resident.

Meantime, the Northwestern Health Health Unit says it’s important to continue to get booster doses for COVID-19 vaccinations.

Dr. Kit Young Hoon says there is evidence that the first or second dose starts to drop.

“The vaccine protection does wane somewhere around the six month mark, maybe a little bit earlier or a little bit later, depending on the individual,” says Dr. Young Hoon.

“So its important to have some sense what’s going on, with respect to vaccination policy, and know when you might be eligible in the future for your next dose.”

She adds vaccination criteria hasn’t changed that much over the past few months.

“If its been more than three month since you had COVID then you should be looking to book an appointment for your booster dose. There is added benefit from and protection from a booster dose so you have significantly reduced risk of severe illness and decreased risk from being infected.”

Dr. Young Hoon expects fourth dose eligibility will decrease from 60 years of age and older over the next few months, and the vaccine for kids under the age of five should be available later this summer.

For information on vaccinations, visit Northwestern Health Unit

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