The Covid Delta Variant: How Effective Are The Vaccines
Analysis: what protection do they offer against infection, hospital admission and death?
As lockdown easing in England is delayed from 21 June to a possible date of 19 July amid concerns of a substantial wave of hospitalisations due to the Delta variant of coronavirus, we take a look at the latest data on the protection offered by vaccines.
Ve High Against Severe Disease
The other two studies focused on hospitalization and ED or UC clinic visits during the Delta variant’s emergence.
The veterans study consisted of 388 COVID-positive and 787 COVID-negative participants who sought healthcare for COVID-like symptoms at five Veterans Affairs medical centers. Almost 14% of the case-patients and 48.0% of the controls were fully vaccinated with Pfizer or Moderna. VE against hospitalization actually went up from its pre-Delta to its post-Delta period .
The overall VE rate against hospitalization was 86.8%, but the researchers note that veterans 65 years or older had a lower rate of 79.8%, compared with 95.1% in those younger. No difference was found between people who were fully vaccinated less than 90 days before their qualifying test and those who had been vaccinated longer
The findings were encouraging to the researchers, as their cohort included demographics shown to be more vulnerable during the pandemic.
Most were men, older , or non-White . Additionally, 44.4% had a Charlson comorbidity index score of 3 or above, and common health conditions included obesity , diabetes , artherosclerotic cardiovascular disease , and chronic obstructive pulmonary disease .
As for the other test-negative study, the researchers used the VISION Network to look at 32,867 medical encounters from 187 hospitals and 221 EDs and UC clinics in nine states from June to August after Delta became the dominant COVID strain.
Pfizer Booster Vs Omicron
Early analysis from the United Kingdom has suggested that boosters have moderate to high vaccine effectiveness against symptomatic infection, offering 70 to 75 percent protection in the initial weeks after the booster.
Researchers found a slight difference depending on whether the initial doses were from the AstraZeneca vaccine or Pfizer-BioNTech vaccine. Both groups had Pfizer-BioNTech boosters.
Two weeks after a Pfizer-BioNTech booster dose, vaccine effectiveness for people who received the AstraZeneca vaccine increased to around 71 percent and to about 76 percent for those who initially got the Pfizer-BioNTech vaccine.
As for severe disease, modeling by Imperial College London found that the Pfizer-BioNTech vaccine with a booster was around 85.9 percent effective against Omicron, compared with about 97 percent against Delta.
Early data from Pfizer had indicated that a booster dose significantly increased neutralizing antibodies, bringing the vaccines protection close to what two doses provided against the original variant of the coronavirus.
The data comes from a series of lab experiments testing the neutralizing ability of blood samples from people who had two doses of the vaccine and those who had received a booster.
The neutralizing ability of the antibodies collected from those who did not have a booster had a more than 25-fold decline against Omicron than the original variant.
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Prior Covid Infection More Protective Than Vaccination During Delta Surge
La’nya Middleton, 14, is treated for the coronavirus disease at the Children’s Hospital of Georgia in Augusta, Georgia, U.S., January 14, 2022. REUTERS/Hannah Beier
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Jan 19 – People who had previously been infected with COVID-19 were better protected against the Delta variant than those who were vaccinated alone, suggesting that natural immunity was a more potent shield than vaccines against that variant, California and New York health officials reported on Wednesday.
Protection against Delta was highest, however, among people who were both vaccinated and had survived a previous COVID infection, and lowest among those who had never been infected or vaccinated, the study found.
Nevertheless, vaccination remains the safest strategy against COVID-19, according to the report published in U.S. Centers for Disease Control and Prevention Morbidity and Mortality Weekly Report.
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The results do not apply to the Omicron variant of the virus, which now accounts for 99.5% of COVID-19 cases in the United States.
“The evidence in this report does not change our vaccination recommendations,” Dr. Ben Silk of the CDC and one of the study’s authors told a media briefing.
“We know that vaccination is still the safest way to protect yourself against COVID-19,” he said.
That represented a change from the period when the Alpha variant was dominant, Silk told the briefing.
Do We Need New Vaccines
So far, vaccines have proven very effective against all mutations of concern. Riese said vaccines will have to be adapted when they lose their effectiveness. Nevertheless, one shouldn’t be too hasty, she warned: “A vaccine isn’t developed that quickly either. If a mutant is created every quarter, we can no longer keep up with vaccine development.”
It is also possible that a vaccine adapted to a particular variant could become obsolete when that strain mutates again.
Virologist Weber sees things a little differently. “You should adapt the vaccines right away,” he said, adding the major studies that have to be done before approval for use take a lot of time.
According to vaccine manufacturer BioNTech-Pfizer, it is already in the process of developing a vaccine specifically designed to combat the delta variant. The first clinical studies are scheduled to begin in August.
Researchers at Berlin’s renowned Charite Hospital also assume COVID-19 vaccinations will have to be checked regularly during the pandemic and adjusted if necessary. At the moment, the virus is changing rapidly, as there are many infections worldwide and the virus can therefore develop more quickly, according to a press release.
As soon as the situation has stabilized, he said, vaccinations will likely be able to be used for longer periods of time.
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Is Delta More Deadly
The WHO says this variant of concern has an increased risk of hospitalisation. This is unsurprising because increased transmissibility could go hand-in-hand with case severity until most of the worlds population is vaccinated.
, yet to be peer-reviewed, compared non-variants of concern with Delta. It found people infected with the Delta variant were:
- 105% more likely to be hospitalised
- 241% more likely to be admitted to an intensive care unit
- 121% more likely to die from the disease.
For the other three variants of concern, these values were 52%, 89% and 51% respectively. This shows the Delta is the most problematic variant of concern to date.
Woman: Getting: Covid: Vaccine
A trio of studies in Morbidity and Mortality Weekly Report today show that COVID vaccines protect very well against the Delta variant, with unvaccinated people having 5 times the risk of infection and more than 10 times the risk of hospitalization or death compared with vaccinated people.
Researchers analyzed data that included the period of Delta variant dominance in the United States, and their results indicate that the Pfizer/BioNTech, Moderna, and Johnson & Johnson vaccines all show strong vaccine effectiveness against severe COVID-19.
The new data join several studies published this week on high COVID-19 VE.
In the first of today’s studies, which looked at US incidence rate ratios , the researchers found that, after Delta became the predominant strain, VE for full Pfizer or Moderna vaccination was 90% against hospitalization and 91% against death. But VE dropped from 91% to 78% for any adult COVID-19 infection during the Delta period.
While the IRR study’s 570,000-case cohort had a larger pool than the other MMWR studies, those two showed similar patterns. Both used test-negative designs, with a veterans-focused one suggesting a VE of 86.8% against COVID-19 hospitalization and a nine-state surveillance study suggesting a VE of 86% against hospitalization and 82% against emergency department and urgent care clinic visits.
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J& j: Vaccine Protection Against Delta Variant Is Strong
July 8, 2021 — The single-shot Johnson & Johnson COVID-19 vaccine provides at least eight months of immunity to the coronavirus and shows âstrong, persistentâ protection against the delta variant, the company said in a news release.
The findings come from two small-sample preprint studies which have not been peer reviewed. The study on variants found the J& J vaccine âelicited neutralizing antibody activity against the Delta variant at an even higher level thanâ against the beta variant first found in South Africa, according to the July 1 news release.
As for the durability of the vaccine, the eight-month study period showed it âgenerates a strong neutralizing antibody response that does not wane rather, we observe an improvement over time,” said Mathai Mammen, MD, of the J& J research and development department.
The study may help allay concerns about whether people whoâve gotten the J& J vaccine needed a booster shot to guard against the delta variant, which is now the dominant form of the coronavirus in the United States, according to new data from the CDC.
âWe believe that our vaccine offers durable protection against COVID-19 and elicits neutralizing activity against the Delta variant. This adds to the robust body of clinical data supporting our single-shot vaccineâs ability to protect against multiple variants of concern,â Paul Stoffels, MD, J& Jâs chief scientific officer, said in the company news release.
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How Covid Vaccines Work Against The Delta Variant
Here is what you need to know about the efficacy of coronavirus vaccines against the variant first identified in India.
The Delta variant of coronavirus is a source of serious concern as lab tests have shown it is more contagious and resistant to vaccines compared with other forms of COVID-19.
However, there is evidence that the available jabs retain important effectiveness against it after two doses.
Here is what you need to know:
A British study published in The Lancet medical journal in early June looked at levels of neutralising antibodies produced in vaccinated people exposed to the Delta, Alpha and Beta variants.
It found that antibody levels in people with two doses of the Pfizer-BioNTech shot were six times lower in the presence of the Delta variant than in the presence of the original COVID-19 strain on which the vaccine was based.
The Alpha and Beta variants also provoked lower responses, with 2.6 times fewer antibodies for Alpha and 4.9 times fewer for Beta.
A French study from the Pasteur Institute concluded that neutralising antibodies produced by vaccination with the Pfizer-BioNTech jab are three to six times less effective against the Delta variant than against the Alpha variant.
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Does Pfizers Booster Shot Protect Against Omicron
They found a 41-fold drop in the ability of the antibodies to neutralize the omicron variant compared with the original virus, a dramatic reduction from its performance against the original ancestral strain as well as other variants, according to a preprint of the study that hasnt yet been peer-reviewed. Vaccine-induced antibodies dropped threefold in their ability to neutralize the earlier beta variant that previously dominated South Africa, suggesting omicron is much better at evading protection.
Mom: On: Couch: With: Sick: Boyjpg
While COVID-19 vaccines lower the likelihood of infection with the highly transmissible SARS-CoV-2 Delta variant, the virus can still be transmitted within householdsbut less so than among unvaccinated peoplea study today in The Lancet Infectious Diseases finds.
Led by Imperial College London researchers, the study evaluated community COVID-19 transmission and viral loads among 602 vaccinated and unvaccinated contacts of 471 mildly ill coronavirus outpatients ages 5 years and older from Sep 13, 2020, to Sep 15, 2021. For up to 20 days, 133 participants contributed 8,145 upper respiratory tract samples, regardless of whether they had symptoms.
Of 205 household contacts of COVID-19 patients infected with Delta, 62% had received two vaccine doses, 19% had received one dose, and 19% were unvaccinated.
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Why Is There A Residual Risk Despite Double Vaccination
None of the vaccinations that have been approved so far provide 100% protection against a coronavirus infection studies have shown that since their introduction.
Vaccinated people, particularly those with preexisting illnesses, still run the low risk of becoming infected and in the worst case, dying. However, the current death rate in the UK remains low, despite rising infection rates.
One of Germany’s leading virologists, Christian Drosten, said in a Coronavirus Update podcast in June that there were “cases where people who are double-vaccinated also die.” He suggested that experts look carefully at the exact cause of death and how the diagnosis was made.
Virologist Christian Drosten said we need to look carefully at the actual cause of death in delta variant cases
The high proportion of vaccinated individuals among the dead is probably due to the fact that about half of the population is now fully immunized, combined with the fact that numbers of overall deaths are dropping.
Moreover, according to PHE’s data, 116 of the 118 people who died were over the age of 50.
Peggy Riese, a scientist at the Helmholtz Center for Infection Research , explained the scenario with the help of a concrete example. “If 100% of a population is vaccinated, then a few people who are vaccinated also die,” she told DW. She said that doesn’t mean the vaccine isn’t safe, just that it doesn’t provide 100% protection.
Test Positive Cases And Test Negative Controls
We did separate analyses for each SARS-CoV-2 variant, selected on the basis of scientific relevance and prevalence in the KPSC population. These included delta , alpha , epsilon , gamma , iota , mu , and other . We defined test positive cases as the first specimen positive for SARS-CoV-2 identified by whole genome sequencing. We examined cases for which whole genome sequencing failed as a separate category . We defined test positive cases admitted to hospital with covid-19 as a variant with specimen collection date no more than seven days before or during hospital admission with covid-19 confirmed by chart review. We randomly selected test negative controls from eligible people with a negative SARS-CoV-2 test. We matched cases and controls 1:5 on age , sex, race/ethnicity , and specimen collection date .
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Does The Vaccine Stop The Delta Variant
The Centers for Disease Control and Prevention released a new study that found vaccine effectiveness against COVID-19 infection dropped from 91% to 66% when the delta variant became the majority of virus cases.
- While we did see a reduction in the protection of the COVID-19 vaccine against the delta variant, its still a two-thirds reduction of risk, the studys lead author, Ashley Fowlkes, an epidemiologist for CDC COVID-19 Emergency Response, told CNN.
The study suggests that there are minor infections among fully vaccinated people, especially due to the delta variant, which has shown to be highly transmissible.
- The study did not review the severity of the disease, though. That said, COVID-19 vaccines remain majorly effective at stopping severe COVID-19 illness from all known variants, according to CNN.
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.
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There Is Emerging Evidence Showing That Existing Covid
Key points:
- The AstraZeneca, Pfizer, and Moderna vaccines effectively protect against COVID-19 infection, illness, hospitalisation, severe illness, and death due to the Delta variant.
- Evidence is emerging showing that it is highly likely that the vaccines reduce the risk of transmission and the length of time a person is infectious.
- Unvaccinated people are significantly more likely to experience symptoms, be sicker, and die from COVID-19, including the Delta variant.
- People who have only had one dose of a vaccine are more protected from COVID-19, including the Delta variant, than unvaccinated people.
- People who have received both doses are more protected than people who have received one.
- The effectiveness of the vaccines reduces over time, but is still at least as effective as the protection afforded by a previous natural infection.
- Vaccination does not prevent infection and transmission completely, so following public health orders, local social restrictions remain important for vaccinated people.
- If exposed or infection is suspected, fully vaccinated people should still be tested for COVID-19 and isolate while awaiting results based on local directions.
There have been reports that herd immunity may be challenged by the emergence of the Delta-variant. However, the evidence shows that vaccination remains very strong and important protection for both vaccinated people and unvaccinated people such as children and others who cannot yet receive the vaccine.
References
Data Suggests Johnson & Johnson Vaccine Still Effective Against Delta Variant
Angela Underwood’s extensive local, state, and federal healthcare and environmental news coverage includes 911 first-responder compensation policy to the Ciba-Geigy water contamination case in Toms River, NJ. Her additional health-related coverage includes death and dying, skin care, and autism spectrum disorder.
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More Data On The Delta Variant And Covid
The new CDC study comes as new data from Israel suggests the vaccines protection against the delta variant will lessen with time. Officials in Israel said the mRNA COVID-19 vaccines might not be totally effective at stopping the delta variant. Though the vaccines can stop the delta variant, theyre less effective against delta than previous mutations.
In fact, Israel one of the highest vaccinated places in the world with 78% of those 12 years old and up fully vaccinated with the Pfizer COVID-19 vaccine has been suffering from one of the worlds highest infection rates recently due to the delta variant, according to Science Magazine.
- More than half are in fully vaccinated people, underscoring the extraordinary transmissibility of the delta variant and stoking concerns that the benefits of vaccination ebb over time, per Science Magazine.
In response, Israel has started to release a third COVID-19 vaccine shot known as a booster to help people stay safe from COVID-19, especially if the vaccines effectiveness is waning, as I wrote for the Deseret News. The U.S. has been reviewing Israel from data as it plans to release its own COVID-19 booster shots to the American people.