Wednesday, September 27, 2023

Which Vaccine Is Better Against Delta Variant

What About Side Effects With Booster Shots

J& J vaccine holds up well against delta Covid variant

The CDC stated that side effects with the third shot “were similar to that of the two-dose series.”

The most common symptoms include fatigue and pain at the injection site, but “most symptoms were mild to moderate.”

As with previous doses of the vaccine, the CDC notes that, “serious side effects are rare, but may occur.”

A New Study Of Us Patients Suggests That Moderna’s Covid

Turns out not all mRNA-based COVID-19 vaccines are equally effective against the constantly mutating coronavirus. New real-world data suggests that Modernas mRNA-1273 vaccine may be more effective than the Pfizer-BioNTech shot against the Delta variant thats been ravaging the world lately.

According to a study pre-print published on medRxiv on Sunday, first reported by the New York Post, the Pfizer-BioNTech vaccines overall effectiveness against COVID-19 dropped to 42 percent in July from the 76 percent recorded in early 2021 before the Delta variant emerged. Meanwhile, the Moderna vaccines efficacy fell only slightly to 76 percent from 86 percent over the same period.

The report, which has yet to be peer-reviewed, studied more than 50,000 patients in the Mayo Clinic Health System, which operates hospitals in Minnesota, Iowa and Wisconsin.

The Delta variant has been present for only a few months, and its pattern suggests that infections rise and decline rapidly, making it hard to study its behavior in a particular region. Real-world data collected so far have produced varying findings on FDA-authorized vaccines effectiveness on the dangerous strain.

An Israeli study last month based on data from June and July showed that the Pfizer-BioNTech vaccine was just 39 percent effective in preventing symptomatic infections caused by the Delta variant.

Both vaccines reported 95 percent efficacy rates against the original strain of COVID-19 during clinical trials.

Vaccines Not As Effective Against Delta Variant Say Cdc Data

CDC data cut to the heart of just how much protection COVID-19 vaccines offer infection preventionists and other health care professionals on the frontlines from the delta variant.

A trio of studies2 by the Centers for Disease Control and Prevention released yesterday, and 1 by Oxford University investigators released last weekseem to indicate that the effectiveness of COVID-19 vaccines wanes in the face of the delta variant. Investigators in the 3 studies agree that their findings present an argument that as many people as possible should be vaccinated against COVID-19.

One of the CDCs studies cuts to the heart of just how much protection COVID-19 vaccines offer infection preventionists and other health care professionals on the frontlines. Vaccine effectiveness in protecting frontline workers decreased nearly 30 percentage points since the delta variant became the dominant strain.

The study, published in the CDCs Mortality and Morbidity Weekly Report , also says that despite evidence of waning, the vaccines are still 80% effective in protecting frontline health care workers.

The CDC investigators, who belong to the CDC COVID-19 Response Team, looked at data from reverse transcriptionpolymerase chain reaction tests for 4217 health care workers, first responders and other frontline workers in 8 locations across 6 states. The delta variant was considered the dominant strain when it accounted for over 50% of cases around those locations.

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Are Booster Shots The Answer

Several more countries, including the U.S. and the U.K., are now offering or planning to offer third doses of Covid-19 vaccines to help boost immunity to the virus that may have depleted.

According to Gideon Schreiber, a professor at Israel’s Weizmann Institute of Science, booster shots may become a necessity.

“Unfortunately, it’s not even annually, it will be twice annually,” he predicted. “The virus has a huge potential for new variants, many which will work to silence immunity so there’s a chance that we’ll need further boosters in the future.”

Schreiber added that Israel’s booster program appeared, so far, to be a big success. After a second dose, he told CNBC, people were four or five times less likely to become severely ill with Covid. But after a third dose, they were more than ten times less likely to become severely ill with the virus.

However, Reithinger argued that booster shots were not necessarily a logical step at this point in time.

“There is only limited data available that an immune response that was primed by available vaccines is waning after six to eight months,” he told CNBC via email. “Most of the data is on infection, rather than hospitalization or death. The data also doesn’t account for the use of non-pharmaceutical interventions, such as masking and social distancing, that in many contexts should continue to be used and adhered to. The only population groups for which the case for booster shots can be made is the immunocompromised.”

Impact Of The Delta Variant On The Vaccine Efficacy

Is my COVID vaccine effective against the Delta variant?

For the vast majority of vaccines approved and distributed in many countries, Phase II/III clinical studies were completed before the Delta variant outbreak, and their efficacies were mainly based on populations exposed to the D614G, Alpha, Beta, and Gamma variants. The spread of the Delta variant challenges their real-world protection efficacy . In the mass vaccination campaign in the United Kingdom, ChAdOx1 and BNT162b2 vaccines were administered to the adult population in two shots. Real-world data obtained from October 2020 to May 2021 showed that the two vaccines have similar efficacies after one shot, with protection rates against the Alpha and Delta variants of 51.1% and 33.5%, respectively. However, protective efficacies of BNT162b2 after two shots against the Alpha and Delta variants were significantly higher than those after two shots of ChAdOx1 . These results are basically consistent with data from Scotland . On the whole, BNT162b2 is superior to ChAdOx1 in protecting against the Alpha and Delta variants.

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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.

Two Doses Of Vaccine Highly Effective Against Delta Variant Uk Officials Say

Two doses of the Pfizer-BioNTech or the AstraZeneca Covid-19 vaccines are highly effective against hospitalization from the Delta variant of the coronavirus, according to a new analysis from Public Health England released Monday.

The variant, which was first identified in India, has become the predominant strain in the United Kingdom. A previous analysis from PHE suggested that a single dose of the vaccine was less effective against symptomatic illness caused by the Delta variant compared to the so-called Alpha variant, or B.1.1.7, which swept the U.K. in the winter.

Full coverage of the coronavirus outbreak

The new analysis found that two doses of the Pfizer vaccine were 96 percent effective against hospitalization from the Delta variant, and two doses of the AstraZeneca vaccine were 92 percent effective.

The second shot is critical, said Dr. Paul Offit, a vaccine researcher at the Children’s Hospital of Philadelphia. We know from the phase one studies that the second shot induces a level of virus-specific neutralizing antibodies thats about tenfold greater than that after the first dose.

The PHE analysis included 14,019 cases caused by the Delta variant in England 166 of which resulted in hospitalizations from April 12 to June 4.

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Canadian Study: Pfizer 87% Effective After Two Doses Moderna 72% After One Dose

A Canadian study posted on Saturday, July 3, found that two doses of a COVID-19 vaccine worked as well against Delta as they did against the Alpha variant, which was previously dominant in the US.

The study hasn’t been scrutinized by experts in a peer-review.


  • 56% effective from 14 days after first dose, 87% effective after two doses.


  • 67% effective from 14 days after first dose. Not enough data for two doses.


  • 72% effective from 14 days after first dose. Not enough data for two doses.

Are Booster Shots Already Authorized

Which vaccine is better against covid variants?

Following these findings, both Pfizer and Moderna have been seeking authorization for their respective booster shots from countries that have already authorized their main COVID-19 vaccines.

So far, the Food and Drug Administration has the distribution of third booster shots of both the Pfizer and the Moderna COVID-19 vaccines but only for those who are immunocompromised, and therefore at higher risk of infection with emerging variants of SARS-CoV-2.

Israel has also recently authorized the distribution of third shots of the Pfizer vaccine, which is now available to people over 50, healthcare workers, people with severe risk factors for the coronavirus, prisoners and wardens.

While the United Kingdom has not yet authorized additional booster shots, unofficial reports indicate it has ordered millions of extra doses for a COVID-19 vaccine booster campaign in fall 2022.

We have secured access to more than 500 doses of COVID-19 vaccines, and we are confident our supply will support potential booster programs in the future. The potential booster program will be based on the final advice of the independent , the Department of Health and Social Care told The Guardian.

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See How Vaccines Can Make The Difference In Delta Variants Impact

The Delta variant, the highly transmissible version of the coronavirus that now makes up almost all new cases in the United States, continues to drive a surge throughout the country, with average new cases topping 100,000 for the past week.

Some of those infections have been reported in fully vaccinated people in so-called breakthrough cases. As the sheer number of those vaccinated increases, so will the raw number of breakthrough cases, especially with the Delta variant circulating. But experts say breakthrough cases do not mean the vaccine is ineffective.

The Delta variants dominance is new enough that authoritative data does not yet exist, but the available data shows that unvaccinated people are still much more likely to contract Covid-19 and far more likely to experience symptomatic disease, while vaccines drastically reduce the risk of hospitalization and death from the virus.

Heres how a Delta-driven outbreak might unfold in two hypothetical groups of people, all of whom are exposed to enough of the virus to infect a person:

In either scenario, the infected group is just the start. The Delta variant is the most transmissible version of the virus yet. Those infected are likely to spread the virus to others at an even higher rate than older versions of the virus would have spread.


Comparison With Other Studies

During the delta phase of the pandemic, breakthrough infections among fully vaccinated people have occurred, but the effectiveness of covid-19 vaccines against severe disease has remained robust. In our study, vaccine effectiveness against admission to hospital with the delta variant was high . Only five fully vaccinated people with the delta variant were admitted to hospital, no fully vaccinated people with non-delta variants were admitted, and no deaths in hospital occurred among any fully vaccinated people. This finding is consistent with previous studies suggesting that fully vaccinated people with breakthrough infections tend to have attenuated viral load, fewer symptoms, and shorter duration of illness, although severe outcomes can still occur.

Our real world findings complement existing immunogenicity and follow-up data from phase III trials of protection by mRNA-1273 against SARS-CoV-2 variants, including delta. High concentrations of neutralizing antibodies to delta and other variants were elicited following two doses of mRNA-1273. These antibodies were found to persist six months after vaccination, albeit at reduced concentrations compared with peak activity. Among phase III trial participants, incidence rates of covid-19 and severe covid-19 during the months when delta was predominant were lower among those who were vaccinated with mRNA-1273 more recently compared with those vaccinated initially .

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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.

Avoiding The Worst Outcomes

Delta 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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Vaccines Effective Against Delta Variant

COVID-19 vaccines are effectiveat preventing hospitalizations and emergency department visitscaused by the Delta variant, according to data from a national study.That data also indicate thatModernasvaccineis significantly more effective against Delta than Pfizer and Johnson & Johnson.

These real-world data show that vaccines remain highly effective at reducing COVID-19 related hospitalizations and emergency department visits, even in the presence of the new COVID-19 variant, said study author Shaun Grannis, M.D., M.S., Regenstrief Institute vice president for data and analytics and professor of medicine at Indiana University School of Medicine. We strongly recommend vaccinations for all who are eligible to reduce serious illness and ease the burden on our healthcare system.

The Centers for Disease Control and Prevention s VISION Network analyzed more than 32,000 medical encounters from nine states during June, July and August2021, whentheDelta variantbecamethe predominant strain. The results showed that unvaccinated individuals with COVID-19 are 5-7 times more likely to need emergency department care or hospitalization, similar to the overall effectiveness prior to the variant.

The studyinMorbidity and MortalityWeekly Reportisalso the first analysis from the VISION Network to show a marked difference between the effectiveness of the mRNA vaccines .In the studys time period:

Scientists say these findings need further monitoring and evaluation.

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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Very High Levels Of Protection Against Hospitalization

A recent analysis from PHE looks at how likely people who had an infection with the delta variant were to need treatment in the hospital.

The report puts the protection from requiring hospital treatment for COVID-19 at 71% after one dose and at 92% after two doses of the Oxford-AstraZeneca vaccine. The Pfizer vaccine was 94% effective at preventing hospitalization after the first dose and 96% after two doses.

In India, the Oxford-AstraZeneca COVID-19 vaccine bears the name Covishield.

The report, which has not been peer-reviewed yet, puts these percentages on a par with protection against the alpha variant, or B.1.1.7, which scientists first identified in the U.K.

These findings indicate very high levels of protection against hospitalization with the delta variant with one or two doses of either vaccine, the authors write.

It comes after an earlier report that indicates COVID-19 vaccines were less effective at protecting people from COVID-19 if they had only received the first dose of the Pfizer-BioNTech or Oxford-AstraZeneca vaccines.

However, in the analysis, which has not yet undergone peer review, the researchers measured any symptomatic case of COVID-19, regardless of severity.

Will A Booster Shot Be Needed

Covid vaccines ‘still effective’ against Delta variant – BBC News

On Aug. 12, the FDA authorized a third dose of either the Pfizer or Moderna COVID-19 vaccine for people who have a weakened immune system for reasons such as being an organ transplant recipient, having an autoimmune disease, or receiving treatment for cancer.

But the FDAs authorization did not extend to J& J vaccine recipients. Because the J& J clinical trials started after those for Pfizer and Moderna, and because the vaccine was authorized later than the other two, the agency is still awaiting study results that would allow for a second dose recommendation, Reategui Schwarz explains. The interim results of the two-dose regimen trial are expected to be released later this summer, according to a spokesperson at Janssen, the company that makes the J& J vaccine.

Were still looking into data on safety and effectiveness of mixing and matching, she says. For J& J recipients who want another shot, I would say please wait until we have more safety and efficacy data.

However, some other countries have moved forward with advising people who got a dose of the AstraZeneca vaccine which, like the J& J vaccine, uses an adenovirus to follow it with a dose of one of the mRNA vaccines. One study in Spain found that people who received a dose of the Pfizer vaccine after a first dose of AstraZeneca elicited a stronger immune response. Similar trials with the J& J vaccine are ongoing.

Still, those who were vaccinated with the J& J vaccine can feel confident that they are well protected.

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