Wednesday, September 27, 2023

Which Vaccine Is Best Against Delta Variant

Uk Study: Pfizer 80% Effective After Two Doses 67% For Astrazeneca

Experts Say COVID Vaccine Is Best Protection Against New Delta Variant

A UK-based study posted on August 24 examined vaccine effectiveness against any COVID-19 infection, including asymptomatic illness. It hasn’t been formally scrutinized by other experts.


  • 80% effective after two doses, at least 14 days after the second dose.


  • 67% effective after two doses, at least 14 days after the second dose.

Who Can Get A Moderna Booster Shot Right Now

On Nov. 19, all US adults — those age 18 and older — became eligible to receive COVID-19 booster shots. They qualify if it’s been at least six months since they’ve received a second dose of either the Moderna or Pfizer vaccine. Those who received the Johnson & Johnson vaccine are eligible for a booster dose after two months. Adults are encouraged to get whatever booster dose is available to them, even if that means mixing and matching vaccine boosters , in other words, getting a different booster shot than their original vaccination.

Vaccines Effective Against Most Sars

Two of the commonly used coronavirus vaccines provide protection against multiple variants of the virus that causes COVID-19, including the highly infectious Delta variant, a new Yale study has found.

The findings, , also show that those infected with the virus prior to vaccination exhibit a more robust immune response to all variants than those who were uninfected and fully vaccinated.

The results come as an increase in so-called breakthrough infections caused by the Delta variant among vaccinated individuals continues to raise questions about whether the vaccines offer broad protection against newly arising variants.

According to the researchers, the Moderna and Pfizer-BioNTech vaccines do bolster the immune systems response to infection.

Vaccines induce high levels of antibodies against Delta and most variants, said Akiko Iwasaki, the Waldemar Von Zedtwitz Professor of Immunobiology and co-corresponding author of the paper. And two shots are better than one.

In addition, the results suggest that booster shots can be effective in warding off SARS-CoV-2, the authors say.

The researchers then exposed the volunteers blood samples to 16 different SARS-COV-2 variants, including the Delta variant, the most predominant strain circulating in the United States, and then measured antibody and T cell response to each of the variants.

Other studies have also shown that vaccinated individuals tend to have less severe infections.

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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.

Breakthrough Infections Can Be Expected

J& J

Although were seeing more breakthrough cases in vaccinated people, and studies indicate that vaccine effectiveness against infection is over time, protection against severe disease or death remains strong.

Experts stress that vaccines are highly protective, even if theyre not 100-percent effective.

A preprint study that analyzed 161 vaccine breakthrough infections among 24,706 vaccinated healthcare workers found that although vaccinated people who contract the coronavirus have similar levels of the virus in their noses and throats as unvaccinated people, not all of it is as infectious.

The breakthrough cases presented with mild or asymptomatic infections, of which more than 90 percent were attributed to the Delta variant.

Additionally other experiments also showed that the viral shedding from vaccinated people was lower. Researchers hypothesized this was because some of the virus had already been neutralized by antibodies produced from the vaccine.

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Don’t Let Omicron Crash Your Holiday Gathering Here’s How To Keep Your Family Safe

And those laboratory findings fit with what health officials have observed in the U.K.: “Moderate to high vaccine effectiveness of 70 to 75% is seen in the early period after a booster dose,” the U.K. Health Security Agency reported two weeks ago.

Altogether, these studies show that a third dose gives you the best chance of preventing an omicron infection this winter. For some young and healthy people, catching a mild case of omicron might not be that big of a burden, but a booster still reduces your risk of spreading it to older loved ones or other vulnerable people.

“We definitely need to give this to everyone if we want to prevent omicron from spreading like wildfire or at least, curtail its spread,” Garcia Beltran adds.

Katherine Thompson, an emergency medical technician working as a FEMA contractor, administers a booster shot at a COVID-19 vaccination clinic in Federal Way, Wash., in December. Ted S. Warren/APhide caption

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Katherine Thompson, an emergency medical technician working as a FEMA contractor, administers a booster shot at a COVID-19 vaccination clinic in Federal Way, Wash., in December.

Vaccines 90% Effective Against Adult Deaths

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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The Best Protection For The Most Vulnerable Is Everybody Getting Vaccinated

While the vaccines have generally held up well against the delta variant, some of the people most vulnerable to Covid-19 do not receive the same level of protection.

For people with compromised immune systems, the CDC researchers found that the vaccines were less effective at preventing hospitalization. That finding supported the Biden administrations plan to make those people immediately eligible for a third shot, experts said.

For immunocompromised individuals, its also possible that immunity may wane more over time but that didnt happen, according to this research. Their level of protection appeared to be constant during the six-month period covered by the study.

Vaccines have gotten less effective at stopping Covid-19 in its tracks but are still extremely good at protecting people

The third CDC study evaluated vaccine effectiveness for nursing home residents, a population particularly vulnerable to Covid-19 and one of the first groups to get vaccinated at the beginning of this year. That study did find declining effectiveness over time against any illness for those Americans, from 75 percent pre-delta to about 50 percent post-delta.

It makes sense to give an extra dose of vaccine to vaccinated nursing home residents, Gounder said. But what will have an even bigger impact on protecting those nursing home residents is to vaccinate their caregivers.

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How Effective Is The Moderna Booster Against The Omicron Variant

Studies show Moderna’s vaccine may be best against delta variant | ANC

On Monday, Moderna’s Hoge said early lab research shows its COVID-19 vaccine booster should provide “good protection against the omicron variant,” raising antibody levels approximately 37 fold. For comparision, Pfizer said earlier this month its booster raises antibody levels 25 fold, creating “robust protection” and offering “a sufficient level of protection” against omicron, the company said.

Studies of US cases of the omicron variant appear to support the concern about weakened protection for those who are fully vaccinated with two doses of the Moderna and Pfizer vaccines or one of Johnson & Johnson’s. Dr. Rochelle P. Walensky, CDC director, said on Dec. 10 that 80% of first confirmed US cases with the mutated virus had been fully vaccinated against the disease.

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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.

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.

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Covid Vaccines Protect Against Delta But Their Effectiveness Wanes

A UK study suggests that COVID-19 vaccines are effective against the Delta variant after two doses, although the protection they offer begins to fall after 30 days.Credit: Ian Forsyth/Getty

The PfizerBioNTech and OxfordAstraZeneca COVID-19 vaccines are effective against the highly infectious Delta variant of SARS-CoV-2 but their protection drops away over time, a study of infections in the United Kingdom has concluded.

Researchers at the University of Oxford, UK, and the countrys Office for National Statistics analysed a vast data set comprising the results of 2,580,021 PCR tests to check for SARS-CoV-2 from 384,543 UK adults between 1 December 2020 and 16 May 2021 when the Alpha variant was dominant and 811,624 test results from 358,983 people between 17 May and 1 August 2021, when the Delta variant was more prevalent.

The results, published in a preprint on 19 August, suggest that both vaccines are effective against Delta after two doses, but that the protection they offer wanes with time. The vaccine made by Pfizer in New York City and BioNTech in Mainz, Germany, was 92% effective at keeping people from developing a high viral load a high concentration of the virus in their test samples 14 days after the second dose. But the vaccines effectiveness fell to 90%, 85% and 78% after 30, 60 and 90 days, respectively.

Moderna Vaccine Provides Strong Protection Against Delta Variant In Prison Outbreak Study Shows

Efficacy of vaccines against the Delta (B.1.617.2) variant ...

A Stanford study at a California prison found that although there were more breakthrough COVID-19 infections than before the emergence of the delta variant, vaccinated prison residents had few symptomatic cases.

Elizabeth Chin

When the delta variant of the coronavirus hit the Sierra Conservation Center a low- to medium-security prison for men in California residents who had received the Moderna vaccine were well protected against symptomatic infection, according to Stanford-led research.

The study, published in The New England Journal of Medicine, also found that in the men who had previously been infected with COVID-19, two doses of the Moderna vaccine resulted in additional, substantial protection against the delta variant.

The study is one of the first to analyze the effectiveness of vaccination during an outbreak of the delta variant. The researchers found that although the estimated vaccine effectiveness against infection was substantially lower than that found in studies conducted before the emergence of the delta variant, protection against symptomatic infection remained high . And in men who previously had COVID-19, the vaccine reduced the risk of subsequent infection by 80.5%.

The study also noted that during the height of the pandemic, incarcerated people were infected by the coronavirus at a rate five times higher than the nations general population.

Joshua Salomon

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The Astrazeneca Vaccine Being Marketed Under The Brand Names Covishield Manufactured In India And Vaxzevria Produced In South Korea Was Developed At The Laboratories Of The University Of Oxford The Current Study Was Conducted By A Different Team Of Researchers At The Same University

A new study by researchers at the University of Oxford has found that a booster dose of the AstraZeneca vaccine was able to significantly increase the levels of neutralising antibodies against the Omicron variant of the coronavirus, offering hope that the vaccine could offer some protection against the fast-spreading variant.

The AstraZeneca vaccine, being marketed under the brand names Covishield, manufactured in India, and Vaxzevria, produced in South Korea, was developed at the laboratories of the University of Oxford. The current study was conducted by a different team of researchers at the same university.

The study found that sera obtained from individuals one month after receiving the third dose was able to neutralise the Omicron variant to levels that were comparable to those observed against the Delta variant one month after the second dose.

Also, the levels of neutralising antibodies after the third dose were found to be higher than those observed in individuals who had been previously infected with other variants, including Delta, and recovered on their own, the company said in a statement.

A couple of days ago, AstraZeneca had also unveiled its plans for developing an Omicron-specific vaccine.

Vaccinating children

What We Know About Pfizer

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What About Johnson & Johnson

A new study released Tuesday suggested that the Johnson & Johnson COVID-19 vaccine might not be very effective against the delta and lambda variants. The study was not peer-reviewed or published in a medical journal. But the experts involved in the study do not work for any of the vaccine developers.

The study said people who got the Johnson & Johnson COVID-19 vaccine might need a booster shot to their vaccine in the future, according to The New York Times.

Older: Woman: Getting: Covid: Vax

J& J vaccine holds up well against delta Covid variant

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 .

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Why The Numbers Vary

It becomes harder to measure how well vaccines work in the real world compared with trials, because you can’t control who gets vaccinated and who doesn’t. Other differences between the two groups could influence the risk of getting sick from COVID-19. For example, those who chose not to get vaccinated could also be more likely to put themselves in risky situations that may expose them to the virus.

The numbers can also vary because they depend on other factors, including what you’re measuring, when you measure it, the age of the population you’re measuring it in, and whether people have had previous COVID-19 infections.

Stephen Evans, professor of medical statistics at the London School of Hygiene & Tropical Medicine, told Insider that in general, the more severe the illness caused by Delta, the better the COVID-19 vaccines appeared to work against it. But the evidence on vaccines’ effectiveness wasn’t strong, he said.

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