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Which Vaccine Has The Highest Efficacy

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Which Vaccine Has the Highest Efficacy Against Delta?

But since the J& J vaccines arrival on the scene there have been a number of challenges. A production snafu in the hands of a contract production company contaminated 15 million doses, which had to be destroyed. And in mid-April, the FDA and CDC recommended states pause use of the vaccine as they investigate whether the vaccine triggers a rare but serious side effect the development of diffuse blood clots, even though the few individuals who developed the condition had low platelet levels.

What follows is a head-to-head comparison of the vaccines developed by Pfizer and BioNTech, by Moderna, and by J& J. This article will be updated as developments occur.

Inclusion Criteria For Efficacy Studies

Randomized controlled trials published in peer-reviewed journals indexed by PubMed were included in this analysis. Studies with large numbers of participants in which the outcomes were defined as RT-PCR-confirmed cases by following standard guidelines of the WHO were included in this article. We also included studies where the control group received a placebo or a vaccine other than SARS-CoV-2 and studies where the concentrations of the mRNA vaccines were presented in microgram amounts and the adenovirus vector vaccines in 10101011 virus particles.

The Link Between Myocarditis And Covid

Myocarditis, an inflammation of the heart muscle, became a trending topic this spring when the Centers for Disease Control and Prevention reported that it is monitoring a small number of cases of heart inflammation that have arisen in young adults not long after mRNA COVID-19 vaccination. The side effect is considered important but uncommonarising in about 12.6 cases per million second doses administered. And now the Food and Drug Administration has announced it will place a warning on the mRNA vaccines. Its important to note that the vaccination is still recommended for everyone who is eligible.

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Herd Immunity: An Explanation

Before the COVID-19 pandemic, the term herd immunity was possibly something you only heard about during flu season or during reports of upticks in measles casesif at all.

But COVID-19 has brought that conceptwhen an infectious disease is less likely to spread because enough people have immunity either through exposure or vaccinationto the front of our minds. Now that we have effective coronavirus vaccines, many are wondering if and when we will reach herd immunity with COVID-19.

Manisha Juthani, MD, and other Yale experts explain herd immunity, why it matters, and what needs to happen to get there.

Why Get The Covid


Sandra Trevino, LCSW, is a founding member of Yales Cultural Ambassadors programa 10-year-old organization whose mission is to broaden community participation in clinical trials at the Yale Center for Clinical Investigationand is doubling her efforts to help educate people about COVID-19 vaccines.

In December, the Kaiser Family Foundation released results of a survey in which more than one-quarter of Americans said they would probably or definitely not get the vaccine. Republicans, and rural and Black Americans were most hesitant, according to the survey.

Its a great responsibility to make sure we continue to address the elephant in the room, which is mistrust with regard to the vaccines, says Trevino.

In a recent interview, she explained why shes encouraging everyone to get the COVID-19 vaccine and talked about her own familys experience with COVID-19.

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The Vaccine Is Here: Your Questions Answered

The new COVID-19 vaccine is here. But its still hard to know exactly what this will mean in our individual and collective lives.

For questionsbig and smallwe went to our foremost expert for a frank, socially distanced question-and-answer session. Onyema Ogbuagu, MBBCh, is a Yale Medicine infectious diseases specialist and the principal investigator of the COVID-19 vaccine studies supported by the Yale Center for Clinical Investigation at Yale School of Medicine, in partnership with the Yale New Haven Health System.

The Johnson & Johnson Vaccine And Blood Clots: What You Need To Know

In the minds of many, the halt of the Johnson & Johnson vaccine in April delivered doubt just as the mass COVID-19 vaccinations were making progress. There are three vaccines authorized for use in the United States, but Johnson & Johnsons was a particularly important one, partly because its one-shot dose made it seem as though we might achieve herd immunity faster. Then, the government recommended pausing the companys vaccine after six women who received it developed rare blood clotsand one woman died.

We spoke to Yale Medicine infectious diseases expert Jaimie Meyer, MD, MS, and Yale Medicine hematologist Robert Bona, MDthey shared insights about the pause and answered commonly asked questions.

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How Is Cerebral Venous Sinus Thrombosis Diagnosed

To diagnose CVST, doctors collect a medical history, perform a physical exam, and order imaging studies and bloodwork.

The doctor will gather information about the medical history, including what symptoms are present, when they began, whether symptoms have worsened in recent days, and whether there are any underlying medical conditions associated with CVST.

During the physical exam, the doctor will evaluate the patient for signs and symptoms associated with CVST.

Imaging studies are essential to diagnosis of CVST. The most commonly used imaging tests for CVST are magnetic resonance imaging and computed tomography scans. The doctor may also order a magnetic resonance venogram or CT venogram of the brain. These are special types of scans that are used to visualize the veins and venous sinuses, which are the structures involved in CVST. In some cases, doctors may recommend another type of imaging study called an angiogram. This test produces an image of the blood vessels in the brain.

A diagnosis of CVST may also require blood tests to evaluate potential underlying causes. In some cases, the doctor will perform a lumbar puncture to collect cerebrospinal fluid for testing.

Does Age Matter For Vaccinations

China’s Sinovac vaccine has efficacy of 50.4% in Brazil trials

Pfizer’s vaccine is also currently the only vaccine authorized for emergency use in children as young as 12. Both Moderna and J& J’s vaccines can only be used on people 18 and older.

What about younger kids? According to experts, those under 12 likely won’t be able to receive the COVID vaccine until later this year or early next year.

Both Pfizer and Moderna have started studies in the U.S. surrounding the vaccine and children ages 6 months to 11 years. Results on those studies could come sometime in the fall.

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Who Can Get A Moderna Booster Shot Right Now

As of Nov. 19, all US adults — those age 18 and older — are eligible to get a booster shot of the COVID-19 vaccine. 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.

How Effective Are The Pfizer Moderna And Astrazeneca Covid

By the Specialist Reporting Team’s Leonie Thorne

When COVID-19 vaccines were being developed, manufacturers had to hit an efficacy rate of 50 per cent before their jabs could get approval.

Most vaccines now in common use exceeded expectations, with efficacy rates as high as 95 per cent, and all three vaccines now available in Australia are significantly slowing hospital admissions and deaths.

However, some studies published in recent weeks appear to show some vaccines might have a slight edge over others, and some may have longer-lasting protection.

So what should we make of all of this? And does it actually matter?

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Will A Booster Shot Be Needed

So far, there has been no recommendation from the Centers for Disease Control and Prevention surrounding booster shots with the Delta variant.

Still, health experts have repeatedly cautioned that COVID-19 booster shots could be needed for fully vaccinated people, particularly as new variants spread.

White House chief advisor Dr. Anthony Fauci said during an interview with MSNBC’s Medhi Hasan in April that people may need to get booster shots in a year.

Pfizer CEO Albert Bourla also previously said people will “likely” need a third dose within 12 months of getting fully vaccinated.

So far, studies suggest that the vaccines currently in use can recognize the emerging variants but they may not provide quite as much protection against the new strains.

Boosters and new versions of vaccines that target the variants are already being explored.

Pfizer-BioNTech was previously testing a third booster shot of its vaccine on fully vaccinated people.

“The flexibility of our proprietary mRNA vaccine platform allows us to technically develop booster vaccines within weeks, if needed,” Sahin said in a release in February.

Moderna was also testing a potential third dose of its current vaccine, and a possible booster shot specifically targeting the South Africa variant. Citing early data, the company recently said the booster vaccine generated a promising immune response against the B.1.351 and P.1 variants first identified in South Africa and Brazil, respectively.

Vaccine Protection And Infection

Top Chinese official admits vaccines have low ...

Vaccines can stop most people from getting sick with COVID-19, but not everyone.

Even after someone takes all of the recommended doses and waits a few weeks for immunity to build up, there is still a chance that they can get infected. Vaccines do not provide full protection, so breakthrough infections where people get the virus, despite having been fully vaccinated will occur.

If vaccinated people do get sick, they are likely to have milder symptoms, in general ‘It is very rare for someone vaccinated to experience severe illness or die.

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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.

We found that vaccines continue to provide significant protection against symptomatic infection with the Delta variantall surpassed the 50% minimum threshold recommended by the World Health Organisation. And they provided even better protection against hospitalisation. But some results are more impressive than others.

These findings have implications for the trajectory of the pandemic. They make Chinas zero-covid strategy, for example, look even less tenable, since the two most widely used Chinese vaccines appear among the least effective at limiting transmission of the Delta variant.

Moderna Booster Shot Update: New Guidance Programs Stats To Know As Omicron Arrives

Booster shots for Moderna and Pfizer are now strongly urged by scientists as the omicron COVID variant appears in the US.

The Moderna booster is here. The CDC recommends you get one.

On Thursday, President Joe Biden announced a new campaign to bring COVID vaccine boosters to 100 million people who are still eligible to receive them. Biden’s campaign, which also includes testing kit reimbursement and stricter travel rules for international travelers, is driven by the emergence of the omicron variant, which has been confirmed in California and Minnesota over the last two days, and which has been detected in 30 countries.

While much is still unknown about the vaccine response to the new omicron variant, health professionals believe that booster shots from Moderna and Pfizer could help slow the spread — along with hospitalization and deaths — as the effects of the vaccine weaken over time.

Scientists and the Centers for Disease Control and Prevention now consider booster shots part of being fully protected for people who received two doses of Moderna or Pfizer after six months, and one dose of Johnson & Johnson after two months.

Here’s what you need to know about the Moderna booster, including its side effects. For more details, here’s the latest on COVID-19 vaccines for kids, how you can get a free COVID-19 test kit soon, how to get a free ride to your booster appointment, and what to know about breakthrough infections.

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Panel: Advice On Vaccinating Children And On The Booster Campaign

The Joint Committee on Vaccination and Immunisation advises that the following groups of children and adolescents are offered a vaccine:

  • Young people aged 16 to 17 years of age who are at higher risk of serious COVID-19
  • Children aged 12 to 15 years with severe neuro-disabilities, Downs syndrome, immunosuppression and multiple or severe learning disabilities
  • Children and young people aged 12 to 17 years who live with an immunosuppressed person
  • All young people aged 12 to 17 years of age should be offered a first dose, and those aged 16 and 17 years should be offered a second dose three weeks after the first. Children who have had a proven SARS-CoV-2 infection should wait at least 12 weeks before receiving a dose of the vaccine.

The JCVI advises that a booster vaccine dose is offered no earlier than 6 months after completion of the primary vaccine course to the following groups:

  • Those living in residential care homes for older adults
  • All adults aged 40 years or over
  • Frontline health and social care workers
  • All those aged 16 to 39 years with underlying health conditions that put them at higher risk of severe COVID-19, and adult carers
  • Adult household contacts of immunosuppressed individuals


Illustrations: Alisdair Macdonald

Clearing the COVID-19 backlog

Inclusion And Exclusion Criteria

Why you can’t compare Covid-19 vaccines

We included published phase 3 RCTs to evaluate the vaccine’s efficacy to prevent symptomatic COVID-19. The following publications were excluded from analysis: phase 1 and phase 2 RCTs, non-randomized trials, observational studies, duplicated reports, pharmacokinetic studies in healthy adults, reviews, expert opinion, editorials, letters to the editor, and comments.

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Data Sources And Search Strategy

We performed a comprehensive database search which included PubMed/Medline, Embase, including Mesh/Emtree terms search, Clinical Trials Registry, and The Cochrane Library using the following keywords: COVID-19, severe acute respiratory syndrome coronavirus, Coronaviridae Infections, coronavirus, sudden acute respiratory syndrome, vaccines, vaccine, randomized controlled trial, controlled clinical trial, clinical trial, phase II/III, phase III. The search strategies incorporated index terms and text words for the search concepts. The search words are detailed in online-only supplements. Databases were searched up to August 30, 2021, without language or date restrictions.

The primary outcomes were the clinical efficacy of the vaccine against symptomatic laboratory-confirmed COVID-19. Secondary outcomes were the efficacy to prevent severe COVID-19 infection and vaccine efficacy among the elderly.

The systematic review and network meta-analysis were performed following Preferred Reporting Items for Systematic Reviews and Meta-Analysis 2020 framework guidelines. The protocol was registered in the International Prospective Register of Systematic Reviews on February 5, 2021 .

Vaccine Efficacy Effectiveness And Protection

This article is part of a series of explainers on vaccine development and distribution. Learn more about vaccines from how they work and how theyre made to ensuring safety and equitable access in WHOs Vaccines Explained series.

COVID-19 vaccines have proven to be safe, effective and life-saving. Like all vaccines, they do not fully protect everyone who is vaccinated, and we do not yet know how well they can prevent people from transmitting the virus to others. So as well as getting vaccinated, we must also continue with other measures to fight the pandemic.

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Continued Research Vigilance Needed

“The fact that the vaccine appears to be preventing symptomatic disease, including with the new variant of concern, is encouraging and this is likely to have a significant impact on case detections and severe outcomes at a population level,” the researchers wrote.

Study coauthor Mary Ramsay, MD, PHE’s head of immunization, said in a PHE news release that more research is still needed. “While there remains much more data to follow, this is encouraging and we are increasingly confident that vaccines are making a real difference,” she said.

Because significant numbers of those vaccinated go on to become infected with coronavirus and may spread it, vaccinated people must remain vigilant, especially in the first 2 or 3 weeks, the authors said. “It is important to remember that protection is not complete and we dont yet know how much these vaccines will reduce the risk of you passing COVID-19 onto others,” Ramsay said. “Even if you have been vaccinated, it is really important that you continue to act like you have the virus, practise good hand hygiene, and stay at home.”

The high efficacy achieved after one dose of vaccine motivated the United Kingdom to offer only one dose to as many people as possible before offering second doses, to maximize coverage. The researchers said that their findings support this strategy.

Estimating Vaccine Efficacy For Covid

CDC: this season

Currently, the IHME model uses the following inputs of vaccine efficacy, separated by variant:

  • Efficacy at preventing symptomatic disease this is operationalized as a reduction in hospitalization and death
  • Efficacy at preventing infection this is operationalized as a reduction in susceptibility
  • At present, our model only distinguishes between ancestral and Alpha combined and the three main variants of concern combined . Due to this current limitation and given that Delta is the predominant variant of concern, we preferentially use data on Delta where this is available.

    Wherever data are available we use available data, and where we do not yet have data, we take different approaches based on variant, vaccine, and outcome. Estimates are generated for each vaccine and outcome as described below.

    To estimate efficacy at preventing disease for ancestral and Alpha

    To estimate efficacy at preventing disease, we use the result from the corresponding clinical trials as documented in Table 1.

    For other mRNA vaccines, we assume the same efficacy as Pfizer-BioNTech.

    For all vaccines, we assume 75% efficacy.

    To estimate efficacy at preventing infection for ancestral and Alpha

    For AstraZeneca and Johnson & Johnson, we use the efficacy as reported in the clinical trials as documented in Table 1.

    For Pfizer-BioNTech and Moderna, we use the infection-to-disease efficacy ratio from the Israel study of the Pfizer-BioNTech vaccine.


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