Vaccines Extremely Effective Against Covid Variants Of Concern: Canadian Study
Whether it’s Pfizer, Moderna or Astra Zeneca, the vaccines used in Canada ‘are doing exactly what they should be doing,’ including against the Delta variant
By Patricia TrebleJuly 5, 2021
People receive a dose of the COVID-19 vaccine at a mass vaccination clinic at Scotiabank Arena in Toronto on Sunday, June 27, 2021. THE CANADIAN PRESS/Cole Burston
Researchers around the world are sifting through data to determine how the leading COVID-19 vaccines are doing against the variants of concern. Now, a big pre-print study from Ontario suggests that the vaccines used in CanadaPfizer, Moderna and AstraZenecaare very effective against the four big variants of concern: Alpha , Beta , Gamma , and Delta .
Our findings suggest that even a single dose of these three vaccine products provides good to excellent protection against symptomatic infection and severe outcomes caused by the four currently circulating variants of concern, and that two doses are likely to provide even higher protection, the authors concluded. The studys results showed that being fully vaccinated gives a person roughly the same protection against Delta as Alpha, Beta and Gamma. The data shows that the vaccines are doing even better than previous studies suggested against the variants in terms of symptomatic infection as well as hospitalization and death.
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1st dose: 88% effective
2nd dose: n/a
Older: Woman: Getting: Covid: Vax
A pair of new real-world COVID-19 vaccine studies show good protection against the Delta variant, one from Scotland finding higher than 90% effectiveness in preventing death in adults and the other showing 93% efficacy against symptomatic infection in Israeli adolescents after the second dose.
Both studies were published as letters today in the New England Journal of Medicine .
Us Study Says Vaccines Is Effective Against Delta Variant Of Covid
Study author Shaun Grannis, vice president for data and analytics at Regenstrief Institute in the US, stated, “These real-world data show that vaccines remain highly effective at reducing COVID-19 related hospitalisations and emergency department visits, even in the presence of the new COVID-19 variant. We strongly recommend vaccinations for all who are eligible to reduce serious illness and ease the burden on our healthcare system,” Grannis said in a statement.
The scientists highlighted that the VISION Network of the Centers for Disease Control and Prevention analysed more than 32,000 medical encounters from nine states in June, July, and August 2021, when the Delta variation became the prevalent strain.
According to the findings, unvaccinated persons with COVID are 5-7 times more likely to require emergency care or hospitalisation, which is comparable to the overall effectiveness prior to the variation.
The study published in Morbidity and Mortality Weekly Report, a weekly epidemiological digest for the United States published by the Centers for Disease Control and Prevention, is also the first analysis from the VISION Network to show a significant difference in the effectiveness of the mRNA vaccines.
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Vaccination Is The Best Protection Against Delta
The most important thing you can do to protect yourself from Delta, Omicron, or any COVID-19 variant is to get fully vaccinated, the doctors say. Recommendations for boosters and who is eligible to get one have been changing, and .
Meanwhile, experts continue to recommend infection prevention strategies, including following its latest guidelines on wearing masks, washing hands, being careful around crowds, social distancing, and testing.
Note: Information provided in Yale Medicine articles is for general informational purposes only. No content in the articles should ever be used as a substitute for medical advice from your doctor or other qualified clinician. Always seek the individual advice of your health care provider with any questions you have regarding a medical condition.
Unvaccinated People Are At Risk
In the U.S., there was a disproportionate number of unvaccinated people in Southern and Appalachian states, where vaccination rates were low at the time of the Delta surge, but cases rose in other parts of the country as well. In September, health leaders in Idaho, which had one of the lowest vaccination rates in the country, expanded health care rationing throughout the state after the Delta surge led to a scarcity of resources for all hospitalized patients.
Children, teenagers, and young adults were a concern, too. A study from the United Kingdom showed that children and adults under 50 were 2.5 times more likely to become infected with Delta, said Dr. Yildirim. The U.S. had allowed Pfizer-BioNTech vaccinations for adolescents and teenagers since May 2021, and, in early November, the CDC approved FDA authorization of the Pfizer vaccine for children ages 5-17.
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Low Protection After 1 Dose
One dose of either vaccine conferred much lower protection against Delta than Alpha .
But two doses of either vaccine were much more effective against both strains . Two doses of the Pfizer vaccine were 88.0% effective against Delta, compared with 93.7% against Alpha. The AstraZeneca vaccine was 67.0% effective against Delta and 74.5% effective against Alpha after two doses.
“We found that the absolute difference in vaccine effectiveness against symptomatic disease with one dose of vaccine with the delta variant as compared with the alpha variant was approximately 12 to 19 percentage points,” the study authors wrote. “However, the differences in vaccine effectiveness after two doses were small.”
The researchers noted that both vaccines were highly effective against both Delta and Alpha after two doses but that effectiveness against either variant was smaller among AstraZeneca recipients than those given Pfizer. They added that the numbers of cases and follow-up periods in the study were not sufficient to allow estimation of vaccine effectiveness against hospitalization or death.
“Overall, we found high levels of vaccine effectiveness against symptomatic disease with the delta variant after the receipt of two doses,” the authors said. “These estimates were only modestly lower than the estimate of vaccine effectiveness against the alpha variant.”
What About Hospital Admissions
Protection against severe disease is a crucial metric, not least for assessing the potential pressures a new wave of infections could place on health services. The good news is that for this outcome the jabs appear to offer similar protection against both variants.
According to an analysis by PHE, the Pfizer/BioNTech jab was linked to a 94% vaccine effectiveness against hospital admission with the Delta variant after one dose and 96% after two doses, while the figures for the Oxford/AstraZeneca jab were 71% and 92% respectively.
This protection against hospital admission is similar to that for the Alpha variant, for which the Pfizer figures were 83% and 95% after the first and second jabs respectively, and 76% and 86% respectively for the AstraZeneca jab.
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Higher Effectiveness Against Delta Infection
One dose of vaccine was 56.7% effective against Delta infection and 20.4% effective against Omicron.
Vaccine effectiveness of two doses of the Moderna COVID-19 vaccine against Omicron infection was 44.0% at 14 to 90 days but fell quickly. Three doses, however, resulted in a VE of 93.7% against Delta at 14 to 60 days and 86.0% after 60 days.
Against Omicron infection, VE after three doses was 71.6% at 14 to 60 days and 47.4% after 60 days.
Three doses were 29.4% effective against Omicron infection among 30 people with compromised immune systems, compared with 75.5% in their non-immunocompromised counterparts. An analysis that excluded people with impaired immune systems showed a three-dose VE against Omicron infection of 51.2% after 60 days.
The full three-dose vaccine regimen was 70.9% effective against Omicron infection in participants older than 65 years, while it was 64.3% among their younger peers. VE after the same regimen against Omicron infection in COVID-naïve patients older than 65 years was 70.1% , while it was 64.5% in younger patients.
Patient And Public Involvement
Although study participants contributed in important ways to this research, no patients were involved in the design, conduct, reporting, or dissemination plans of our research. This regulatory commitment study was discussed in public meetings of the Vaccines and Related Biological Products Advisory Committee and Advisory Committee on Immunization Practices.
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Vaccine Progress In The Us
The United States has so far administered more than 382 million doses of COVID-19 vaccines.
More than 179 million people are fully vaccinated. That means over 63 percent of the U.S. population over age 12 is fully vaccinated.
There are currently three COVID-19 vaccines authorized by the Food and Drug Administration for use in the United States.
The Pfizer-BioNTech vaccine was the first to receive
. More than 14 million doses have been administered so far.
We broke down what the current data says. New research could mean this data will change over time.
Deltaand Omicronand The Risk Of ‘hyperlocal Outbreaks’
If Deltaand later the Omicron variantcontinued to accelerate the pandemic, Dr. Wilson said the biggest questions would be about the heightened transmissibility. The answer could depend, in part, on where you liveand how many people in your location are vaccinated, he said. I call it patchwork vaccination, where you have these pockets that are highly vaccinated that are adjacent to places that have 20% vaccination, Dr. Wilson said. The problem is that this allows the virus to hop, skip, and jump from one poorly vaccinated area to another.
In some cases, a low-vaccination town that was surrounded by high vaccination areas could end up with the virus contained within its borders, and the result could be hyperlocal outbreaks, he said. Then, the pandemic could look different than what weve seen before, where there are real hotspots around the country.
So, instead of a three- or four-year pandemic that peters out once enough people are vaccinated, an uptick in cases would be compressed into a shorter period of time. That sounds almost like a good thing, Dr. Wilson said. Its not. If too many people are infected at once in a particular area, the local health care system will become overwhelmed, and more people will die, he said. Thats something we have to worry about a lot.
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Vaccines Are Effective Against Delta And More Science Journal News
The latest roundup of pandemic findings gathered by The Tyee.
Brian Owens is a freelance science writer and editor based in St. Stephen, New Brunswick. His work has appeared in Hakai Magazine, Nature, New Scientist, the Canadian Medical Association Journal and the Lancet.
New England Journal of Medicine
Compiled by veteran medical journalist Brian Owens, this roundup of some of the newest science on the COVID-19 pandemic, straight from the scientific journals, is presented by Hakai Magazine in partnership with The Tyee.
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Vaccines still effective against Delta variant
The Delta variant of COVID-19 has become dominant around the world, but so far vaccines appear to be holding up well against it. A new study has found that a two-dose regimen of the Pfizer-BioNTech shot was 88 per cent effective at preventing symptomatic disease from the Delta variant, compared to 93.7 per cent against the Alpha variant. A two-shot regimen of the AstraZeneca vaccine was 67 per cent effective against the Delta variant, higher than the 60 per cent originally reported, and 74.5 per cent effective against the Alpha variant.
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A Third Dose Of Covid
Israel became the first country to widely administer an additional dose of COVID-19 vaccine for people at higher risk. Currently, people 60 or older can get a third dose of the Pfizer-BioNTech vaccine as a booster.
The Israeli Health Ministry said its decision was based on national health statistics, which suggested that people vaccinated in April appeared to have 75 percent protection against infection, while protection for people vaccinated in January dropped to as low as 16 percent.
Venky Soundararajan, PhD, who led the abovementioned Mayo Clinic study, said a Moderna booster shot is also in the works. It may be recommended for people who got the Pfizer-BioNTech or Moderna vaccines earlier this year.
Other countries, such as the United Kingdom, Spain, and Germany, have also approved third doses to be administered to people who do not mount a proper immune response after getting their initial two doses.
The United States is also one of them.
The CDC has so far only recommended a three-shot regimen to boost protection for immunocompromised people, such as organ transplant recipients and people with cancer, who received either the Pfizer-BioNTech or Moderna vaccine.
The United States also has a booster plan that would offer people either Pfizer-BioNTech or Moderna boosters 8 months after their second dose. The rollout is expected to start Sept. 20.
Moderna also said on Sept. 9 that its working on a single vaccine that combines both a COVID-19 booster dose and a flu shot.
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Pfizer 93% Effective Against Symptomatic Infection In Teens
In Israel, the Clalit Research Institute, in conjunction with Harvard University, conducted an observational study involving 130,464 COVID-19naïve adolescents aged 12 to 18 years, half of whom were vaccinated with the Pfizer COVID-19 vaccine from Jun 8 to Sep 14, 2021 matched participants were unvaccinated. During the study, 13,423 unvaccinated participants were vaccinated.
At the time of the study, Delta was responsible for more than 95% of new infections in Israel. The study is the largest peer-reviewed look at COVID-19 vaccine efficacy among adolescents in a nationwide setting and the first such study conducted at a time when Delta was the dominant circulating strain.
Over a median of 27 days after receipt of the first vaccine dose, Kaplan-Meier curves for infection showed a similar incidence of infection in the first few days after the vaccinated group received their first dose, after which the rise in incidence slowed among the vaccinated.
Estimated effectiveness of the Pfizer vaccine against infection was 59% 14 to 20 days after the first dose, climbing to 66% on days 21 to 27 and 90% 7 to 21 days after the second dose.
Efficacy against symptomatic COVID-19 was estimated at 57% 14 to 20 days after the first vaccine dose, rising to 82% on days 21 to 27 and to 93% 7 to 21 days after the second dose.
How Effective Is Pfizer Against Delta Heres What We Know
Is the Pfizer/BioNTech vaccine 88% or 41% effective against the Delta variant?
After a study in England found the Pfizer/BioNTech Coronavirus vaccine to be 88% effective against the Delta variant, data from Israel suggests just 41% effectiveness.
The contradictory results has created confusion in the media. For example, a Forbes article claimed “Israel’s findings the most up to date and accurate assessment of the Pfizer shot against Delta,” which implies that Israel’s report is more reliable because it’s more recent. That’s not necessarily true.
Which is the correct figure for how well Pfizer’s vaccine works? And why is there such a big difference in the effectiveness estimated by the two countries?
Comparing the English and Israeli results is challenging because there are at least three potential sources of uncertainty that might influence the figures for efficacy.
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The Mrna Jabs Seem Bestbut All Offer Protection
THE RESULTS OF the first trial that showed that a vaccine could prevent symptomatic cases of covid-19, in November 2020, were greeted by the media with delight. As Nature put it: It works!. But the emergence of variants of SARS-CoV-2, the virus that causes covid, complicated the picture, since vaccines may work well against one variant, but not against another. Understanding the shots effectiveness against Delta, the variant that is now globally dominant, is a pressing concern.
The Economist has collected what is possibly the largest set of vaccine results against the Delta variant, in terms of hospitalisation and symptomatic infection. We looked at results from a host of real-world and phase-three clinical trials of vaccines approved by American and European regulators, such as those made by AstraZeneca and Moderna, as well as shots made elsewhere in the world, including by Chinas Sinovac and Sinopharm, Indias Bharat Biotech, which makes Covaxin, and the Russian vaccine, Sputnik V. Our comparison is not perfect. Differences might arise from variations in the conduct of trials or the rates at which immunity wanes for different jabs. Vaccines whose trials were conducted later after they had been administered, or on more vulnerable populations, might appear worse than similarly protective jabs.
Editors note : This article has been updated to provide more details of the trial in St Petersburg.
If I Come Down With Covid
If youve been infected recently in the U.S., theres roughly a one-in-four chance its Delta. Thats because about 25% of coronavirus samples being genetically sequenced these days turn out to be the Delta variant, according to the CDC.
But as in all things related to COVID-19, this varies widely from state to state and even county to county. From Montana to the Dakotas, and from Utah to Iowa and Missouri, the Delta variant now is thought to be responsible for as many as 57% of new coronavirus cases. In the CDC monitoring region made of California, Nevada and Arizona, its making its way up the charts and is now considered responsible for 38% of new cases. Meanwhile, from the mid-Atlantic to New England and in the Pacific Northwest, its just getting started.
If youve been vaccinated with any of the COVID-19 vaccines and are experiencing symptoms, you should get tested. You are unlikely to get very sick, but hospitalizations of vaccinated people are being sporadically reported across the country.
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