Thursday, September 28, 2023

Which Vaccine Is More Effective Against Delta Variant

Coronavirus Infections Expected Among The Vaccinated

Israeli study finds Pfizer vaccine less effective against Delta variant

As part of his argument that the COVID-19 vaccines dont work against delta, McCullough claimed that 42% of 90,000 proven delta cases in the U.K. have been vaccinated.

We asked him for the source of this statement, and he told us it came from the U.K. governments technical briefing on the variants from June 25. But the report actually shows that only 7,235 people out of 92,029 delta cases, or 7.9%, were fully vaccinated, while 58% were unvaccinated and the remainder were partially vaccinated or did not have vaccination information. By inaccurately citing 42%, McCullough gives the false impression that the vaccines are failing on a wide scale against delta.

More important, experts say it can be misleading to look at these kinds of percentages without the larger context. Thats because no vaccine is 100% effective. So as vaccination rates go up, more and more of the people who get COVID-19 will have been immunized, but fewer total people will get the disease.

As more folks get #vaccinated, the % of folks who get sick with #COVID19& happen to be vaccinated will increase. This is expected, explainedMaia Majumder, a computational epidemiologist at Boston Childrens Hospital, on Twitter. t doesnt mean that #vaccines arent working rather, it reflects the realities of probability.

The U.K. and Israel have some of the highest vaccination rates in the world, so their data can be easy to misinterpret.

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.

How Effective Are The Vaccines Against The Delta Variant Compared With The Alpha Variant

In general, Covid jabs are most effective against the most severe outcomes, such as death, and less effective against less severe ones, such as asymptomatic infection.

This appears to be borne out by data collected for the two main Covid jabs in use in the UK against both variants.

According to figures gathered by Public Health Scotland and , at least two weeks after the second dose of Covid jabs, protection against infection fell from 92% for the Alpha variant to 79% against the Delta variant for the Pfizer/BioNTech vaccine, while for the Oxford/AstraZeneca vaccine the protection fell from 73% to 60% respectively.

Protection against symptomatic disease has also been found to differ depending on the variant.

According to the latest figures from Public Health England , four weeks after one dose, either vaccine offered almost 50% protection against the Alpha variant. However for the Delta variant this protection was lower, with one dose of the Pfizer/BioNTech jab offering about 36% protection against symptomatic disease. For one dose of the Oxford/AstraZeneca vaccine this figure was about 30%.

Two weeks after the second dose, the differences in vaccine effectiveness by variant were more modest, with the Pfizer/BioNTech jab offering 88% protection against symptomatic disease with the Delta variant, compared with 94% protection against the Alpha variant. For the Oxford/AstraZeneca vaccine, the figures were 67% and 74% respectively.

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Covid Vaccines Still Effective Against Delta Variant

Senior health, science and environment reporter

Having two doses of Covid vaccine remains the best way to protect against the Delta variant, first identified in India and now dominant in the UK.

The Oxford-AstraZeneca jab, though initially less effective, offers the same high protection as the Pfizer-BioNTech after four to five months, the largest study of its kind suggests.

But neither is as effective as it is against the Alpha variant, responsible for most UK infections last winter.

There is insufficient data for Moderna.

But researchers believe it “almost certainly at least as good as the others”.

They analysed two and a half million tests results from 743,526 participants in the UK’s Covid-19 household-infection survey – led by Oxford University and the Office for National Statistics.

A Third Dose Of Covid

COVID vaccination in Singapore 69% effective against Delta

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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What We Know About Moderna

One lab study of the Moderna vaccine suggested the vaccine could protect against the delta variant but wasnt as protective as it was against the alpha variant. That said, the same study found the vaccine could protect better against the delta compared to the beta version of the virus .


A study from Canada found that the Moderna vaccine was 72% effective against the delta variant after one dose. However, there was not enough data to figure out the effectiveness after two doses. This study was not peer-reviewed.

Which Covid Vaccine Is More Effective Against Delta Variant

This is a dramatic drop in protection from the vaccine’s. The study, conducted by nfrence and the mayo clinic and published to medrxiv on aug.

Encouraging News About Covid-19 Vaccine Against Delta Variant Youtube

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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.

Avoiding The Worst Outcomes

J& J vaccine holds up well against delta Covid variant

Despite the limited data available in the United States, research has found that the J& J vaccine is doing what its meant to do: save lives.

In July, J& J released the results of two studies that found that people who were vaccinated with the single-dose vaccine elicited an immune response against the delta variant and that the immune response lasted for at least eight months.

And in early August, a clinical trial that followed nearly 500,000 health care workers in South Africa found that the J& J vaccine was 71% effective against hospitalization and 95% effective against death due to the delta variant.

While some people who were fully vaccinated did become infected with the virus, the vast majority of those people had mild symptoms that did not require hospitalization.

As the delta variant continues to spread rapidly, breakthrough infections are increasing among recipients of the J& J vaccine as well as the mRNA vaccines, Reategui Schwarz explains. Even so, vaccinated people account for a very small portion of hospitalizations and deaths due to COVID-19 in the United States.

Right now, all the vaccines are still effective against the variants, she says. We havent seen a variant that can fully escape immunity.

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The Johnson & Johnson Covid

Theres little data that shows how effective the Johnson & Johnson single-shot COVID-19 vaccine is at protecting against the Delta variant.

Alpha versus Delta

A clinical trial suggests the vaccine is 85 percent effective against severe disease. In the study, it demonstrated strong, persistent protection against hospitalization and death.

Another study, which has not yet been peer-reviewed and only examined 27 people, suggests the J& J vaccine is 67 percent effective against the Delta variant.

The study also found the vaccine produced fewer antibodies against Delta than it did for the Alpha variant, but scientists say it may not accurately reflect the vaccines real-life performance.

The most recent findings, and the only real-life data, are from South Africa, which suggests that the vaccine offers about 71 percent protection against hospitalization when the Delta variant dominates.

Estimated effectiveness of J& J COVID-19 vaccine

As with other vaccines, the J& J vaccine shows a slight dip in effectiveness against the Delta variant, but more comprehensive studies are needed to reach a definitive answer.

Age Probably Important In Likelihood Of Covid Reinfection

Research shows that age is also likely to play a role in whether we will be reinfected after having had the virus.

A study involving US war veterans, funded by the US Department of Veterans Affairs Office of Rural Health and still in the peer-review process, shows that among senior citizens, mRNA vaccines offered stronger protection against infection, hospitalization and death than prior COVID infections.

But for participants under 65, the protection offered by vaccines was more or less the same as previous infection, the study found. The authors did disclose previous financial support from Pfizer.

Some research suggests that for elderly people, a previous COVID infection is less likely to protect them from reinfection

The study, published in September, supports findings from a population-level Denmark study published in March, which was based on data collected during the second surge of the pandemic in late 2020 before vaccines were widely available. Among younger people who had tested positive during the first wave, protection against repeat infection was around 80%. However among people aged 65 and older, immunity acquired through past infection was only around 47% effective.

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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.

Vaccines 90% Effective Against Adult Deaths

Johnson &  Johnson vaccine less effective against Delta ...

In the most recent results of the UK observational study, a team led by a University of Edinburgh researcher estimated the odds of COVID-19 death among 114,706 vaccinated and unvaccinated Scottish adults who tested positive for COVID-19 from Apr 1 to Aug 16, 2021, and were followed up until Sep 27.

Vaccinees had received one or two doses of the Pfizer/BioNTech or AstraZeneca/Oxford COVID-19 vaccines. Relative to the vaccinated, unvaccinated adults tended to be much younger, have fewer chronic conditions, have lower socioeconomic status, and be men. Whole-genome sequencing showed that nearly all infections were caused by Delta.

Of 201 total COVID-19 deaths, none occurred among the 7,180 fully vaccinated participants 16 to 39 years old, compared with 17 among the 35,449 unvaccinated participants in that age-group . Of participants aged 40 to 59, 33 deaths occurred among the 4,803 unvaccinated participants , versus 18 among 12,905 in the fully vaccinated group .

Overall effectiveness against death from Delta infections at least 14 days after the second vaccine dose was 90% for Pfizer and 91% for AstraZeneca.

Among 40- to 59-year-olds, the vaccines were 88% effective against death for AstraZeneca and 95% for Pfizer. Overall effectiveness against death was 90% with AstraZeneca and 87% with Pfizer among those 60 years and older.

“If you still have not taken up your offer to be vaccinated, I would encourage you to do so based on the clear benefits it offers.”

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Two Doses Of Pfizer Astrazeneca Shots Effective Against Delta Variant: Study

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LONDON, July 21 – Two doses of Pfizer or AstraZeneca’s COVID-19 vaccine are nearly as effective against the highly transmissible Delta coronavirus variant as they are against the previously dominant Alpha variant, a study published on Wednesday showed.

Officials say vaccines are highly effective against the Delta variant, now the dominant variant worldwide, though the study reiterated that one shot of the vaccines is not enough for high protection.

The study, published in the New England Journal of Medicine, confirms headline findings given by Public Health England in May about the efficacy of COVID-19 vaccines made by Pfizer-BioNTech and Oxford-AstraZeneca , based on real-world data.

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Wednesday’s study found that two doses of Pfizer’s shot was 88% effective at preventing symptomatic disease from the Delta variant, compared to 93.7% against the Alpha variant, broadly the same as previously reported.

Two shots of AstraZeneca vaccine were 67% effective against the Delta variant, up from 60% originally reported, and 74.5% effective against the Alpha variant, compared to an original estimate of 66% effectiveness.

“Only modest differences in vaccine effectiveness were noted with the Delta variant as compared with the Alpha variant after the receipt of two vaccine doses,” Public Health England researchers wrote in the study.

Vaccines Vs Delta Variant

Since the Delta variant emerged, scientists have been trying to establish whether the current COVID-19 vaccines are as effective against it.

Recent studies show theres been a slight decrease in observed effectiveness since March, when the Delta variant only made up 7 percent of COVID-19 cases in the United States.

By the time July rolled around, this figure skyrocketed to 94 percent.

Scientists say immunity may wane over time and new more infectious variants in a population may affect vaccine effectiveness, among many other factors.

However, according to the latest study released by the CDC, unvaccinated people are over 10 times more likely to be hospitalized with COVID-19 than vaccinated people.

Unvaccinated people are also 11 times more likely to die of COVID-19 than vaccinated people, the study found.

We broke down what the current data says. New research could mean this data will change over time.

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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.

Test Positive Cases And Test Negative Controls

Pfizer vaccine stats against delta variant

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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