Global Statistics

All countries
527,822,950
Confirmed
Updated on May 23, 2022 3:04 pm
All countries
483,888,406
Recovered
Updated on May 23, 2022 3:04 pm
All countries
6,300,822
Deaths
Updated on May 23, 2022 3:04 pm

Global Statistics

All countries
527,822,950
Confirmed
Updated on May 23, 2022 3:04 pm
All countries
483,888,406
Recovered
Updated on May 23, 2022 3:04 pm
All countries
6,300,822
Deaths
Updated on May 23, 2022 3:04 pm
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How Protective Is One Dose Of Pfizer Covid Vaccine

Further Muddling Vaccine Rollout

One dose of Pfizer or Moderna COVID-19 vaccine shows 80% protection rate: U.S. CDC

Timothy C. Y. Chan, PhD, a professor of industrial engineering at the University of Toronto and the Canada research chair in Novel Optimization and Analytics in Health, tells Verywell that a single dose of mRNA vaccines is an idea worth exploring when supplies are limited or supply chains are interrupted.;

Still, its not a one-size-fits-all approach and there are logistical issues to consider. A regimen that differs from the one laid out by the vaccine manufacturer could add a level of confusion or disorganization to vaccine efforts, he says.;

It does add a bit of an additional challenge when we’re thinking about keeping track of who already has had one dose and making sure they come backto get the second one, he says. What if someone misses their appointment, and they come back a week later and say, Oh, I’d like my shot now.? You’d have to decide, do you give it to this person? Or do you give it to the person who’s getting their first shot?

Logistical issues aside, Raabe says a short delay between the recommended timing between the first and second dose of the Pfizer vaccine may not be cause for major concern, but pushing weeks or months out? Its too early to tell what effects that may have. We dont have good data for what happens when you significantly delay the second dose, she says.;

Efficacy Across Different Groups

A consistently high efficacy was observed in the clinical trials across age groups, sex, race, ethnicity and people with underlying medical conditions.

This means after getting two doses of the Pfizer vaccine, more than 9 out of 10 people are protected against COVID-19 regardless of their age, health status or ethnic group.

Can You Still Get Ill With Covid

The new vaccines are very good, but theyre not perfect, and no vaccine works perfectly for everybody. The highest estimates of their peak efficacy are above 90%, but not quite 100%. After youre vaccinated, it is possible that you could catch Covid-19. But if you do get ill, its much less likely to be severe and youre much more likely to recover without needing to be hospitalised.

Have you read?

Remember, immunity takes weeks to properly develop after getting your first dose, so during that time you may still be at some risk.

Theres also the danger of new coronavirus variants emerging that might be able to avoid the vaccines effects. For example, people have been concerned about the delta variant, first identified in India but now spreading in many countries. Public Health England has looked at how effective the Pfizer-BioNTech and Oxford-AstraZeneca vaccines are against this variant. So far, it seems that the first dose of either vaccine is less likely to stop the variant from causing illness but protection from the second dose is much higher.

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Missed Opportunity To Buy More Pfizer Vaccine

Pfizer officials offered Operation Warp Speed the opportunity to buy more than the initial 100 million doses the government originally ordered, but the Trump administration passed on the offer, the New York Times reported, citing unnamed sources who are familiar with the talks. According to the report, Pfizer gave US officials an option to request 100 million to 500 million more doses and warned that demand could outstrip supply as other governments locked in their orders.

A spokeswoman with the Department of Health and Human Services , when asked if federal officials missed a crucial opportunity to buy up more vaccine, said the government is confident that it will have 100 million doses of Pfizer’s vaccine and anticipates supplies from five other vaccine candidates.

President Trump was expected to sign an executive order today to ensure that Americans will have access to COVID-19 vaccine before it begins helping other nations, Fox News reported.

In other vaccine developments:

What We Know About Using A Single Dose

Pfizer begins trials testing third dose of Covid vaccine

The U.K.’s public health authority published findings that suggest a single shot of the Pfizer vaccine can cut hospitalizations in adults by around 80% three to four weeks after the shot. The U.K. has delayed giving second doses to citizens in order to give more people a single jab first.

Research out of Israel published in The Lancet found that the first dose of the Pfizer COVID-19 vaccine was 85% effective two to three weeks after a single dose. Another study found that after one dose of the vaccine, between days 14 to 20, it offered 57% effectiveness for symptomatic COVID-19, 74% for hospitalization, and 62% for severe disease.

So does the high efficacy of Pfizers vaccine mean that it is time to allow a single dose? In certain circumstances, possibly, Vanessa Raabe, MD, an infectious diseases specialist at the NYU Langone Vaccine Center in New York, tells Verywell, but its too soon to roll out this strategy.

Our data on how well this works is so limited, Raabe says. Studies that have been done for a single dose were not done in a clinical trial; they were done in a real-world setting and only looked really at the first few weeks after the first vaccine dose.

This means what happens in the months following a single dose, and how well protection lasts, is not known. What we do know is how much protection is offered after the two-dose regimen that was studied in clinical trials, she says.;

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Additional Phase 3 Findings

The FDA analysis is based on detailed data that weren’t spelled out in Pfizer’s press release last month that described its initial efficacy findings. The new report appears among documents released ahead of the Dec 10 meeting of the FDA’s Vaccines and Related Biological Products Advisory Committee, which will consider the Pfizer-BioNTech EUA submission.

In November, Pfizer said that after two doses given 3 weeks apart, the vaccine’s efficacy was 95%. But according to the FDA analysis, strong protection of about 82% occurred after the first doses and was 52% between the two doses.

On today, Akiko Iwasaki, PhD, an immunobiologist with the Yale University School of Medicine, said one striking finding was that people were protected as early as 12 to 13 days following the first dose. She added that high affinity antibodies and longer-term immunity will likely require the second dose and that all vaccines should stick to the two-dose regimen.

The findings released last month showed that protection was nearly as high in people over age 65an important risk groupas in younger adults. Likewise, the FDA’s analysis shows that the vaccine also seems to provide equal protection among other groups at risk for more severe disease, including Blacks, Latinos, and those who are obese.

How Effective Is The First Shot Of The Pfizer Or Moderna Vaccine

Editors note: Since this article was initially published, the coronavirus has continued to mutate. This updated version reflects research as of July 2021 suggesting that a single dose of the Moderna or Pfizer COVID-19 vaccine is not enough to reliably ward off infection. The recommendation remains to receive the full course of two shots.

Maybe youve postponed your second COVID-19 vaccine appointment, whether because of scheduling hassles or general reluctance. But how safe are you after just a single dose?

As an immunologist, I hear this question frequently and the answer has changed as new genetic strains of the coronavirus become more common.;, the;delta variant;had become the most dominant strain of SARS-CoV-2 circulating in the U.S.

The Moderna and Pfizer mRNA vaccines werent designed specifically to ward off the delta variant. While overall they still;provide excellent protection;after the full two doses, new research suggests;a single dose provides less immunity;against the coronavirus strains that are out there now than it did against the original strain.

Bottom line: Two shots are way better than one.

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Is The Vaccine Less Effective If You Have A Compromised Immune System

The vaccine may be less effective in some people with compromised immune systems. Even though it may produce a weaker immune response, any added protection against the coronavirus is beneficial.

Immunocompromised individuals are at higher risk for contracting the coronavirus and developing COVID-19, so the extra protection can help keep you healthy. If you are immunosuppressed, talk with your doctor before getting the vaccine.

An Unchartered Situation For All Of Us: From Shipping Containers To Security Concerns A Covid

Pfizer data suggests 3rd dose of COVID vaccine boosts protection against delta variant

Modernas must be shipped at -4 degrees Fahrenheit, which is within the temperature of a regular refrigerator freezer.

After thawing, a vial of the Pfizer vaccine must be used within five days; Modernas is stable at fridge temperature for 30 days and at room temperature for 12 hours. J&Js vaccine can be stored at room temperature not to exceed 77 degrees Fahrenheit ;for 12 hours when the vial hasnt yet been punctured. After the first dose is withdrawn, the vial can be stored in a fridge for six hours or at room temperature for two hours.

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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. The company is also reportedly researching whether a second shot would boost immunity against the variants.

Study 1

A recent clinical trial suggested that the vaccine was 85 percent effective against severe disease and demonstrated strong, persistent protection against hospitalization and death.

It also showed that the J&J vaccine prompted neutralizing antibody activity, which stops the virus from infecting healthy cells, against the Delta variant at a higher level than it did for the beta variant.

The Pfizer-BioNTech and AstraZeneca vaccines had shown a decline in effectiveness against the latter in another study.

Study 2

Interim results from a study involving 20 people have shown that the J&J vaccine neutralized the Delta variant within 29 days of the first shot, and protection improved over time.

Current data for the eight months studied so far show that the single-shot Johnson & Johnson COVID-19 vaccine generates a strong neutralizing antibody response that does not wane; rather, we observe an improvement over time. In addition, we observe a persistent and particularly robust, durable cellular immune response, said Dr. Mathai Mammen, the global head of Janssen Research & Development at Johnson & Johnson, in a July 1 press release.

Study 3

The data has sparked discussions about a possible booster for the one-shot vaccine.

A Single Vaccine Dose Appears To Protect Against Covid

Traducido por;El Planeta Media.

Tucked inside the Food and Drug Administrations analyses of;Moderna and Pfizer’s vaccines was a pleasant discovery: A single injection of either of the two-dose vaccines;appears to provide strong protection against the coronavirus.

With supplies of the vaccines limited and hundreds of millions of people waiting for inoculation this leaves;epidemiologists grappling with a complicated question.;Should the nation vaccinate fewer people with the best protection possible, or provide twice the number of people with a single shot, covering more of the population but;with slightly weaker protection?

question is a really difficult moral and scientific one,” says Barry Bloom, an epidemiologist at Harvard University. “If the second vaccine dose were superfluous, and we knew didnt extend the duration of protection, the principle would be to protect as many people and save as many lives as possible.

The right answer, in other words, depends on science we haven’t;yet completed. For one, the protection from;a single dose of Pfizers vaccine hasnt been definitively tested. Scientists can only infer from the trial data;that Pfizers vaccine would provide protective antibodies to roughly half of people who get one dose.

was not shy about showing that a single dose was so effective, and they do the math right,” Gill says. After 14 days, the vaccine is remarkably effective.

Probably not, but no one knows,;Linas says.;

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Higher Efficacy In Hospitalized Elderly

The other UK study followed patients 80 years or older who had received one COVID-19 vaccine dose at least 14 days prior and who were hospitalized for respiratory symptoms in two National Health Service trusts in Bristol.

From Dec 18, 2020, to Feb 26, 2021, 18 of 135 with COVID-19 infections and 90 of 269 non-COVID patients had one dose of the Pfizer vaccine, suggesting 71.4% adjusted VE . In the same time period, 9 of 36 COVID-19 patients and 53 of 90 non-COVID patients had one dose of the AstraZeneca vaccine, which translates to an estimated adjusted VE of 80.4% .

This may seem like Pfizer is less effective than AstraZeneca, but the researchers found that restricting the Pfizer analysis to the same time period as AstraZeneca’s emergency-use approval increased Pfizer VE to 79.3% .

While the researchers acknowledge that most cases were likely caused by the Alpha variant , they write, “The findings of our case-control analysis will help to guide strategy development for the use of BNT162b2 and ChAdOx1 nCOV-19 vaccines in clinical practice and should reassure policy makers of the high value of deploying these vaccines, and the importance of administering two doses, in high-risk populations in whom incidence of severe disease and death from SARS-CoV-2 infection remains high.”

Newest Data Suggests Second Shot Provides Better Protection Against Variants

More studies show Pfizer and Moderna COVID

Real-word data from the UK posted May 23 by Public Health England showed that Pfizer’s and AstraZeneca’s COVID-19 vaccines worked better against the variants when two doses were given rather than just one. Both vaccines were 30% effective against COVID-19 with symptoms caused by the Delta variant, first identified in India, three weeks after the first dose.;

This was boosted to between 60% and 88% effectiveness two weeks after the second dose. The two vaccines were 50% effective against COVID-19 with symptoms against the variant first found in the UK, Alpha, three weeks after the first dose. This increased to between 66% and 93% two weeks after the second dose.

Dr. Anthony Fauci, President Joe Biden’s chief medical advisor, said on June 8 that getting two doses of COVID-19 vaccines would stop the Delta variant from spreading across the US. In the UK, Professor Deborah Dunn-Walters, chair of the British Society for Immunology COVID-19 Taskforce,;said in a statement on June 4 that two doses of Pfizer’s vaccine were;“critical for protection” against emerging strains of the virus.

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Pfizer Vaccine May Offer Strong Protection After First Dose Israeli Study Finds

The Covid-19 vaccine developed by Pfizer and BioNTech produces a robust immune response after just one dose, according to a new Israeli study of vaccinated health care workers at the country’s largest hospital.

The research, published Thursday in the medical journal The Lancet, followed 7,214 staff members at Israel’s Sheba Medical Center, a government-owned facility, who received their first dose of the Pfizer-BioNTech vaccination between Dec. 19 and Jan. 24. Scientists from the medical center found that the vaccine was 85 percent effective at preventing symptomatic Covid-19 within 15 to 28 days after the shot was administered.

Experts cautioned that more research is needed before broad conclusions can be drawn, but the results do provide some evidence that robust immunity is generated after one dose and that the second dose could be delayed beyond the three weeks prescribed by Pfizer in order to ease distribution and supply constraints.

The timing of the second dose has been the subject of much recent debate, with some countries such as the United Kingdom opting to delay it as a way to speed up the country’s rate of immunization. In the United States, where the vaccine rollout has been bumpy and winter storms over the past week have hampered some states’ ability to administer shots, similar questions have emerged.

How Well The Vaccine Works

  • Based on;evidence from clinical trials in people 16 years and older, the Pfizer-BioNTech vaccine was 95% effective at preventing laboratory-confirmed infection with the virus that causes COVID-19 in people who received two doses and had no evidence of being previously infected.
  • In clinical trials, the Pfizer-BioNTech vaccine was also highly effective at preventing laboratory-confirmed COVID-19 infection in adolescents 1215 years old, and the immune response in people 1215 years old was at least as strong as the immune response in people 1625 years old.
  • The vaccine was also highly effective in clinical trials at preventing COVID-19 among people of diverse age, sex, race, and ethnicity categories and among people with underlying medical conditions.
  • Evidence shows mRNA COVID-19 vaccines offer similar protection in real-world conditions as they have in clinical trial settingsreducing the risk of COVID-19, including severe illness by 90% or more, among people who are fully vaccinated.
  • CDC will continue to provide updates as we learn more.

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Low Protection After 1 Dose

One dose of either vaccine conferred much lower protection against Delta than Alpha .

But two doses of either vaccine were much more effective against both strains . Two doses of the Pfizer vaccine were 88.0% effective against Delta, compared with 93.7% against Alpha. The AstraZeneca vaccine was 67.0% effective against Delta and 74.5% effective against Alpha after two doses.

“We found that the absolute difference in vaccine effectiveness against symptomatic disease with one dose of vaccine with the delta variant as compared with the alpha variant was approximately 12 to 19 percentage points,” the study authors wrote. “However, the differences in vaccine effectiveness after two doses were small.”;

The researchers noted that both vaccines were highly effective against both Delta and Alpha after two doses but that effectiveness against either variant was smaller among AstraZeneca recipients than those given Pfizer. They added that the numbers of cases and follow-up periods in the study were not sufficient to allow estimation of vaccine effectiveness against hospitalization or death.

“Overall, we found high levels of vaccine effectiveness against symptomatic disease with the delta variant after the receipt of two doses,” the authors said. “These estimates were only modestly lower than the estimate of vaccine effectiveness against the alpha variant.”

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