Saturday, September 30, 2023

When Is Pfizer Vaccine Effective

Vaccine Review Approval And Monitoring

Pfizer vaccine less effective after 6 months, study says

Health Canada’s independent drug review process is recognized around the world for its high standards and rigor. Our decisions are based only on scientific and medical evidence showing that vaccines are safe and effective. The benefits must also outweigh any risks.

The Pfizer-BioNTech COVID-19 vaccine was authorized for use in Canada under the Interim Order respecting the importation, sale and advertising of drugs for use in relation to COVID-19. The interim order expired on September 16, 2021. On this date, Pfizer-BioNTech Comirnaty®transitioned to an authorization under the Food and Drug Regulations.

Find detailed technical information such as the product monograph and the regulatory decision summary:

As COVID-19 vaccines are administered across Canada, our safety monitoring is ongoing. The Public Health Agency of Canada, Health Canada, and provincial and territorial health authorities continue to:

  • monitor the use of all COVID-19 vaccines closely
  • examine and assess any new safety concerns

Q: At The Time Of Authorization What Information Was Available About Serious Adverse Events That Occurred During The Clinical Trial In Individuals 16 Years Of Age And Older

A: Serious adverse events, while uncommon , were observed at slightly higher numerical rates in the vaccine study group compared to the saline placebo study group, both overall and for certain specific adverse events occurring in very small numbers. These represented common medical events that occur in the general population at similar frequency. Upon further review by the FDA, these imbalances do not raise a safety concern, nor do they suggest a causal relationship to vaccination for the vast majority of reported serious adverse events.

Serious adverse events considered by the FDA to be plausibly related to the vaccine or vaccination procedure were one case of shoulder injury at the vaccination site and one case of swollen lymph node in the armpit opposite the vaccination arm.

No safety concerns were identified in subgroup analyses by age, race, ethnicity, medical comorbidities, or prior SARS-CoV-2 infection.

Vaccine Protection Against Variants Of The Virus

It is normal for a virus to change. Different variants of the coronavirus SARS-CoV-2 have been found all over the world. Since there are only minimal differences between the variants and the original virus, the vaccine will not immediately become ineffective. Even if a vaccine is slightly less effective against a variant, it can still offer protection against serious illness and death.

When variants of the virus occur, they will be subjected to research at the national and international levels to determine how they respond to the vaccines.

RIVM is also conducting research on variants of the coronavirus SARS-CoV-2. Read more about that research: Variants of the coronavirus SARS-CoV-2.

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What Is It Like To Get A Covid

Two vaccines, one developed by Pfizer-BioNTech and one by Moderna, were each found to be approximately 95% effective in clinical trials and given Early Use Authorization by the Food and Drug Administration in December 2020. And more are on the way. So, the question remains: What is it like to get a COVID-19 vaccine?

We made a list of top concerns and asked Onyema Ogbuagu, MBBCh, a Yale Medicine infectious diseases specialist and Yales leading expert on COVID-19 vaccines, to share insights.

Q: Can You Describe The Mrna Technology Of The Pfizer

1 dose of Moderna, Pfizer vaccines effective against COVID

A: The Pfizer-BioNTech COVID-19 Vaccine contains messenger RNA which is genetic material. The vaccine contains a synthetic piece of mRNA that instructs cells in the body to make the distinctive “spike” protein of the SARS-CoV-2 virus. When vaccinated, the body produces copies of the spike protein, which alone does not cause disease, and the immune system learns to react defensively, producing an immune response against SARS-CoV-2.

FDA scientists have expertise with this technology as it has been used to develop other preventive investigational vaccines that have been tested in human clinical trials. The FDA does not have specific safety concerns with a vaccine that utilizes this technology.

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What ‘pfizer Documents’ Release Reveals

Misleading claims suggesting that more than 1,200 died after suffering adverse reactions to the Pfizer COVID-19 vaccine have once again been spread on social media.

The phrase “Pfizer documents” became a top trending topic on , thanks in part to a tweet posted by Georgia Congresswoman , who previously had her personal Twitter account permanently suspended for “repeated violations” of the social media site’s COVID-19 misinformation policy.

In her tweet, Greene shared a screenshot of a document released by the Food and Drug Administration which she took as meaning that 1,223 people died during “Pfizer’s post authorization adverse events” report. A number of other conservative figures also posted why they are skeptical about the safety of the vaccine with the #pfizerdocuments hashtag.

While the report discussed adverse reactions to the vaccine in a 90-day period and the figures are genuine, the pharmaceutical company has said the documents do not link the vaccine as being responsible for the people’s death.

The report states that of the billions of vaccines shipped worldwide between December 1, 2020, and February 28, 2021, there were 42,086 reported reactions.

These included those who had fully recovered or are recovering from COVID, those who recovered but were still experiencing some symptoms, those not recovered at the time of the report, and the 1,223 who are listed as “fatal.”

The Coronavirus Pandemic: Key Things To Know

Vaccine protection in adolescents.Five months after immunization, two doses of the Pfizer vaccine appeared to offer virtually no defense against moderate illness caused by Omicron among adolescents aged 12 to 17 years, according to new C.D.C. data. Booster shots, however, dramatically increased the protection.

Virus found in deer.Scientists have identified a highly mutated version of the coronavirus in white-tailed deer in Ontario. They also found a similar viral sequence in a person who had close contact with deer, the first evidence of possible deer-to-human virus transmission.

The origins of the pandemic.Scientists released two new studies, yet to be published in a scientific journal, suggesting that the coronavirus originated in a market in Wuhan, China. The researchers said they found no support for the hypothesis that the virus escaped from a lab.

Dr. Philip Krause, who recently retired from the F.D.A. as a senior vaccine regulator, said assumptions about certain antibody levels being predictive of vaccine effectiveness should be re-evaluated in light of the new results.

It certainly weakens the argument for mandating that people get that lower dose, he said.

There are other alternatives that may improve immunity in young children, said Deepta Bhattacharya, an immunologist at the University of Arizona.

Still, the vaccines provide more protection than we think, said Jessica Andriesen, a vaccine data expert at the Fred Hutchinson Cancer Research Center in Seattle.

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Pfizer And Moderna Vaccines Proved Very Effective Against Covid Omicron Variant Study Shows

The two main COVID-19 vaccines used in the U.S., Pfizer-BioNTech’s and Moderna’s, remained highly effective at preventing hospitalization and death from the Omicron variant, even if they were less effective at preventing mild infections, a report released Friday by the Centers for Disease Control and Prevention shows. And people who got a third dose fared best.

Two doses of the vaccines were 79 percent effective at preventing people from dying or going on ventilators during the Omicron surge, the tracking report found, while those who got a booster shot ended up with 94 percent protection. “Anybody who is skeptical really needs to look at that number and think, ‘Okay, maybe I’m going to get a cold and feel sick, but … I’m not going to get put on a ventilator or die,'” Jeanne Marrazzo, director of the Division of Infectious Diseases at the University of Alabama at Birmingham, tells The Washington Post.

The CDC study looked at COVID-19 cases at 21 hospitals in 18 states from March 11, 2021, to Jan. 24, giving researchers a view of how vaccines worked against the Alpha, Delta, and Omicron variants. William Schaffner, an infectious-disease specialist at Vanderbilt University Medical Center, called the report “solid gold.””This is such solid information that reinforces the current recommendation to get vaccinated and boosted and worked for Omicron,” he told the Post.

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How Long Does The Pfizer Vaccine Last

Pfizer vaccine less effective against omicron, new data shows

According to a recent announcement made by Pfizer on April 1, its vaccine offers six months of strong protection against symptomatic COVID-19. The organisation’s phase 3 trial revealed that the Pfizer vaccine was 91.3% effective at preventing COVID-19 for up to six months after the second dose and 100% effective against severe disease, as defined by the CDC. Moderna and Pfizer both have similar results because both the vaccines are based upon a single technology called mRNA.

The studies were conducted before the new variants, or versions, of the coronavirus, had emerged and started to spread in various countries around the world. The new variants or mutations of the COVID19 virus which were not part of the report include B.1.1.7, B.1.351 and P.1 variant strains that originated in the United Kingdom, South Africa and Brazil, respectively. So, as the trials were conducted differently at different times, efficacy rates cannot be directly compared among the vaccines.

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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.

Mrna Vaccines Have Been In Development For Decades

mRNA vaccines have been developed through major international collaboration.

Researchers have studied and worked with mRNA vaccines for decades. This includes studies for vaccines against flu, Zika, rabies and cytomegalovirus .

Scientists have also researched past coronavirus infections . Once scientists identified the coronavirus that causes COVID-19, they could quickly adapt the technology for COVID-19.

Although its relatively new technology, this vaccine has gone through all the usual safety checks and regulations.

This includes international clinical trials to help demonstrate the efficacy and safety of the vaccine. The Pfizer vaccine is being used worldwide and continually and closely monitored for effectiveness and safety.

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How Long After Vaccination Are You Protected Against Covid

  • You are well protected against COVID-19 from 7 days to 14 days after the second vaccination. You may still get COVID-19 after the first vaccination with Pfizer, Moderna or AstraZeneca because your immune response to the virus is not yet fully developed. After the second vaccination, there is a much lower risk of becoming ill, because you are better protected. That is why it is important to get the second vaccination as well. See four reasons why the second vaccination is so important on .
  • You are also sufficiently protected against COVID-19 28 days after one vaccination with the Janssen vaccine.
  • You are also sufficiently protected against COVID-19 14 days after one vaccination with another vaccine, if you had already had COVID-19 before receiving that vaccination.

The vaccination also protects the people around you. You can still become infected if you have been vaccinated. However, you are far less likely to be contagious than if you had not been vaccinated. The main way to minimise the risk to the people around you is to wait at least 14 days after receiving your second vaccination with the Pfizer, Moderna or AstraZeneca vaccines, or at least 28 days after receiving a vaccination with the Janssen vaccine. Even after vaccination, you can still develop symptoms that could indicate COVID-19. Read more about that possibility and about testing and quarantine in the dossier on Quarantine and isolation.

Johnson & Johnson And Guillain

Israelâs âDr. Fauciâ? says Pfizer vaccineâs first dose is less effective ...

Guillain-Barré syndrome is a rare neurological disorder in which the immune system attacks the nerves. It can cause muscle weakness and sometimes paralysis. People usually recover from it, but it can lead to hospitalization and, sometimes, permanent damage to nerve cells.

So, its not surprising that people have questions upon hearing that about 100 suspected cases of GBS have been identified among 12.8 million people who have received the Johnson & Johnson vaccine. While this figure is low enough to categorize the occurrences as rare, the Food and Drug Administration has now attached a warning to the Johnson & Johnson shot about the increased risk of developing GBS in the 42 days after vaccination.

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Q: What Effectiveness Data Supported The Emergency Use Authorization Of Pfizer

A: The data to support the EUA of the Pfizer-BioNTech COVID-19 Vaccine include an analysis of 36,523 participants in the ongoing randomized, blinded, placebo-controlled international study, the majority of whom are U.S. participants, who completed the 2-dose vaccination regimen and did not have evidence of SARS-CoV-2 infection through 7 days after the second dose. Among these participants, 18,198 received the vaccine and 18,325 received saline placebo. The vaccine was 95 percent effective in preventing COVID-19 disease among these clinical trial participants with 8 COVID-19 cases in the vaccine group and 162 COVID-19 cases in the placebo group. Of these 170 COVID-19 cases, 1 in the vaccine group and 3 in the placebo group were classified as severe.

A: The FDA updated the emergency use authorization for the Pfizer-BioNTech COVID-19 Vaccine to allow for the use of a single booster dose administered at least 6 months after completion of the vaccine primary series in individuals:

  • 65 years of age and older
  • 18 through 64 years of age at high risk of severe COVID-19
  • 18 through 64 years of age whose frequent institutional or occupational exposure to SARS-CoV-2 puts them at high risk of serious complications of COVID-19 including severe COVID-19

The primary series for individuals 5 years of age and older consists of two doses.

Why Did The Fda Question The Strength Of J& js Booster Data

Even though the FDA advisory panel unanimously recommended authorization of Johnson & Johnsons booster in October, it also questioned a test used in the trial to support its application for authorization. Regulators questioned the accuracy of a test called pseudovirus neutralization assay , which is used to measure antibodies, suggesting that the low-test sensitivity could have affected the results of the clinical trial.

The upshot, though, is that despite the concern for low sensitivity of the psVNA, the advisory panel still recommended the second dose, said Dr. Sude at the time. They feel that everyone who received a first dose should be given the option to optimize protection based on the best data available at the time.

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Q: What Safety Data Did The Fda Evaluate To Authorize The Pfizer

A: The available safety data to support the EUA include 37,586 of the participants enrolled in an ongoing randomized, placebo-controlled international study, the majority of whom are U.S. participants. These participants, 18,801 of whom received the vaccine and 18,785 of whom received saline placebo, were followed for a median of 2 months after receiving the 2nd dose. This is consistent with the recommendations set forth in the FDAs October 2020 Guidance on Emergency Use Authorization for Vaccines to Prevent COVID-19.

The most commonly reported side effects were pain at the injection site, tiredness, headache, muscle pain, chills, joint pain, and fever. Side effects typically started within two days of vaccination and resolved 1-2 day later. Of note, more people experienced these side effects after the second dose than after the first dose, so it is important for vaccination providers and recipients to expect that that there may be some side effects after either dose, but even more so after the second dose.

The FDA also evaluated additional safety data from the larger database that included participants enrolled later during the study who had shorter follow-up . The FDA determined that the findings were similar to those in the population of participants with a median follow-up of 2 months after the 2nd dose.

How The Pfizer Vaccine Works: Mrna Vaccines

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The Pfizer vaccine is an mRNA vaccine that contains the genetic code for an important part of the SARS-CoV-2 virus called the spike protein. Spike proteins are the little projections on the surface of the virus.

  • Once youve had the vaccine, your body reads the genetic code and makes copies of the spike protein.
  • Your immune system detects these spike proteins and learns how to recognise and fight against COVID-19. It knows it needs to attack the virus to protect it from spreading in your body.
  • The genetic code then gets broken down and removed very quickly and easily by our body.
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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.

    Risk Of Getting Covid

    After the first vaccination, you may still get COVID-19 because your immunity to the virus is not yet fully developed. After the second vaccination, there is a much lower risk of becoming ill because you are better protected. That is why it is important to get both vaccinations. Since the protective effect of the first series of vaccines decreases over time, as of autumn 2021 people can get a booster vaccine. Booster vaccinations will be scheduled old to young. This booster vaccination is intended to boost and improve the effectiveness of the initial series of vaccination.

    Information on how effective the vaccines are is provided on the page about COVID-19 vaccines. All vaccines prevent people from becoming ill due to the coronavirus. However, the vaccines work in different ways. See also the information provided on

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