Tag: Rare

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Health

Experiences of Extreme Covid or Demise After Vaccination Are Uncommon, however Not Surprising

Reports of Severe Covid or Death After Vaccination Are Rare, but Not Unexpected

In the past few months, a constant headline hit has highlighted the amazing effectiveness of Covid-19 vaccines in the field, particularly mRNA vaccines from Pfizer-BioNTech and Moderna. Studies have shown that the vaccines are more than 90 percent effective in preventing the worst outcomes, including hospitalization and death.

But alongside this good news, there have been rare reports of severe Covid in fully vaccinated people.

For example, on June 3, Napa County announced that a fully vaccinated woman who was more than a month after her second Moderna vaccination had died after being hospitalized with Covid. The over 65-year-old woman with previous illnesses had tested positive for the alpha variant identified for the first time in Great Britain.

While these cases are tragic, they are unusual – and not unexpected.

“I am very sad that she had such a serious illness that she actually died,” said Dr. William Schaffner, medical director of the National Foundation for Infectious Diseases and vaccines expert at Vanderbilt University. But, he noted, “we expected the occasional breakthrough infection to occur.”

Such cases shouldn’t prevent people from getting vaccinated, scientists said. “There is no vaccine in history that has ever been 100 percent effective,” said Dr. Paul Offit, the director of the Vaccine Education Center at the Children’s Hospital of Philadelphia. “This is your best chance to avoid serious, critical illness. But as with everything in medicine, it is not perfect. “

Severe Covid is rare in fully vaccinated people. In a paper released last month, the Centers for Disease Control and Prevention said they had received reports of 10,262 breakthrough infections as of April 30. That’s only a tiny fraction of the 101 million Americans who have been vaccinated to that date, though the agency noted that these are likely to be a “significant minority” of breakthrough infections.

Of these groundbreaking cases, 10 percent of patients were hospitalized and 2 percent died – and in some of those cases, patients were hospitalized or died of something unrelated to Covid-19. The average age of the deceased was 82 years.

Updated

June 11, 2021, 2:36 p.m. ET

Older adults, who are at higher risk of Covid complications, are also more likely to develop breakthrough infections as they are known to build weaker immune responses to vaccines. People with compromised immune systems or other chronic health conditions may also be at increased risk.

Some of the variants – especially Beta, which was first identified in South Africa – may be more likely to evade vaccine-induced protection. But beta isn’t common in the United States right now, noted Dr. Conductor.

The alpha variant that infected the Napa County woman is highly contagious, but vaccines offer good protection against it – as well as against the original strain of the virus.

“Breakthrough infection stories, while exceptionally rare, can be confusing to the public,” said Dr. Napa County’s health officer Karen Relucio in an email. “We know that with stories like this one could be tempted to question the effectiveness of vaccines.”

But the vaccines are highly effective, she stressed. In Napa County, the breakthrough infection rate in fully vaccinated people is just 0.04 percent, she said.

Nationwide, the rate is even lower. According to the California Department of Health, there were 5,723 breakthrough cases in more than 17.5 million fully vaccinated residents as of June 2, a rate of 0.032 percent. Of these cases, only 7 percent are known to have been hospitalized and 0.8 percent to have died. In these cases, too, it is unclear whether Covid was the main cause of death.

Breakthrough infections are likely to decline as more people are vaccinated and community transmission rates decline. “The virus will find fewer and fewer people to become infected – it will be more difficult for the virus to get through the population,” said Dr. Conductor. “These are great vaccines. So that the vaccines work optimally – individually and collectively – as many people as possible must be vaccinated. “

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Health

C.D.C. Says Little one Covid Hospitalizations Are Uncommon, however Extra Frequent Than Flu

C.D.C. Says Child Covid Hospitalizations Are Rare, but More Frequent Than Flu

According to a study published Friday by the Centers for Disease Control and Prevention, the number of Covid-19-related hospitalizations among teenagers in the United States over the past three flu seasons has been about three times higher than influenza-related hospitalizations.

The results contradict claims that influenza is more threatening to children than Covid-19, an argument used to reopen schools and question the value of vaccinating adolescents against the coronavirus.

“Much of this suffering can be prevented,” said CDC director Dr. Rochelle P. Walensky, in a statement. “Vaccination is our way out of this pandemic.”

Children are at a much lower overall risk of Covid-19 compared to adults, but it is believed that their likelihood of infection and serious illness increases with age. Since the beginning of the pandemic, the hospitalization rate for children ages 12-17 has been 12.5 times lower than that of adults. However, according to the new report, the rate was higher than in children ages 5-11.

The researchers counted Covid-19 hospital stays in children aged 12 to 17 from March 1, 2020 to April 24, 2021. The data came from Covid-Net, a population-based surveillance system in 14 states that covers about 10 percent of Americans.

The number of adolescents hospitalized for Covid-19 decreased in January and February of this year, but rose again in March and April. Between January 1, 2021 and March 31, 2021, 204 teenagers were likely hospitalized mainly for Covid-19. Most children had at least one underlying medical condition, such as obesity, asthma, or a neurological disorder.

None of the children died, but about a third were admitted to intensive care and 5 percent required invasive mechanical ventilation. About two-thirds of adolescents admitted to the hospital were Black or Hispanic American, reflecting the greater risk the virus poses to these populations.

The researchers compared the numbers for Covid-19 to hospital admissions for flu in the same age group during the 2017-18, 2018-19, and 2019-20 flu seasons. From October 1, 2020 to April 24, 2021, adolescent hospital admission rates for Covid-19 were 2.5 to 3.0 times higher than for seasonal flu in previous years.

The rate could have increased this spring due to the more contagious variants of the coronavirus floating around, as well as the reopening of schools that brought children together indoors and looser adherence to precautions like wearing masks and social distancing, the researchers said .

The data adds urgency to the drive to get more teenagers vaccinated, said Dr. Walensky, who added that she was “deeply concerned” with the numbers.

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Health

FDA official says coronary heart challenge presumably linked to pictures is uncommon

FDA official says heart issue possibly linked to shots is rare

A healthcare worker administers a dose of a Pfizer-BioNTech Covid-19 vaccine to a child at a pediatrician’s office in Bingham Farms, Michigan, U.S., on Wednesday, May 19, 2021.

Emily Elconin | Bloomberg | Getty Images

A heart inflammation condition in adolescents and young adults who received Covid-19 vaccines appears to be very rare and it remains unclear if the issue is actually related to the shots, the Food and Drug Administration’s top vaccine regulator, Dr. Peter Marks, said Thursday.

The Centers for Disease Control and Prevention’s vaccine safety group said last week it was looking into a condition called myocarditis, which is an inflammation of the heart muscle, in a “relatively few” people who received Covid vaccinations.

Myocarditis can affect one’s heart muscle and heart electrical system, “reducing its ability to pump and causing rapid or abnormal heart rhythms,” according to the Mayo Clinic.

The cases were predominantly in adolescents and young adults and usually occurred within four days after getting the shot, according to the CDC. The condition was seen more often in men and most cases appear to be mild, the agency said, though officials are following up with the patients.

“We still don’t know whether this is truly related to the vaccine,” Marks, director of the FDA’s Center for Biologics Evaluation and Research, said during a virtual Q&A event with the COVID-19 Vaccine Education and Equity Project.

The CDC is coordinating its investigation with the FDA, which recently authorized the Pfizer-BioNTech vaccine for adolescents ages 12 to 15. The vaccine has been available for Americans 16 and up since December. Vaccines from Moderna and Johnson & Johnson are available to those 18 and older.

Health experts say finding rare side effects once a vaccine or drug is administered to the general population is common and if myocarditis turns out to be related to the Covid vaccine, the risk is negligible when compared with the risks of being infected with Covid-19.

Marks, who has been at the FDA for nearly a decade, added Thursday that the “handful” of cases reported have been “very mild, lasting a day or two” and usually happened after a second dose.

“My kids are a little older, but I wouldn’t hesitate to vaccinate my children, just because this is a pretty rare finding and we really don’t know yet if it’s truly related” to the vaccines, he said.

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Health

C.D.C Confirms Extra Instances of Uncommon Blood Clot Dysfunction Linked to J.&J. Vaccine

C.D.C Confirms More Cases of Rare Blood Clot Disorder Linked to J.&J. Vaccine

Federal health officials have now confirmed 28 cases, including six in men, of a rare bleeding disorder in adults who have received the Johnson & Johnson Covid-19 vaccine.

Dr. Tom Shimabukuro, deputy director of the vaccination safety bureau at the Centers for Disease Control and Prevention, presented the new cases on Wednesday at a CDC advisory board meeting

The number is an increase from the 15 confirmed cases that were all women reported at the meeting last month.

Although officials have now identified a handful of cases in men, women – particularly between the ages of 30 and 49 – appear to be at increased risk. “The trend is that women in all age groups have higher reporting rates than men,” said Dr. Shimabukuro at the meeting.

Patients with the rare but serious disorder develop blood clots, often in the brain, as well as low levels of platelets, components of the blood that promote clotting. The disorder is a “rare, clinically serious, and potentially life-threatening condition,” said Dr. Shimabukuro.

Last month, after reports first emerged that six women who had received the vaccine had developed the disorder, federal health officials recommended discontinuing use of the vaccine during the investigation. They lifted the suspension 10 days later and warned the vaccine label of possible risks that suggest that there is a “plausible” link between the vaccine and the disease.

22 of the confirmed cases so far involved women and six men. All were adults between the ages of 18 and 59 who received the vaccine before the national break. (Another case was also recorded in a 25-year-old male who participated in the clinical trial.)

Three people have died and four remain in the hospital, including one in intensive care. No new deaths have been documented since last month’s meeting, said Dr. Shimabukuro.

The overall risk remains extremely low. More than 9 million doses of the Johnson & Johnson vaccine have now been administered in the United States.

There were 12.4 cases per million doses in women between 30 and 39 years of age and 9.4 cases per million doses in women between 40 and 49 years of age, the two demographics that appear to be at greatest risk. There were fewer than 3 cases per million doses in older women and men of all ages.

Of the 28 confirmed cases, 12 people who developed the disorder had obesity, 7 had high blood pressure, 3 had diabetes, and 3 were taking estrogen, although it is not yet clear whether any of these factors could significantly increase the risk of the disorder.

Officials will continue to look for cases of the coagulation disorder in vaccinated people, said Dr. Shimabukuro.

There were no confirmed cases of coagulation disorder after the Pfizer BioNTech or Moderna vaccines, which use a different technology, said Dr. Shimabukuro.

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Entertainment

A Uncommon Peek Inside a Semi-Secret ‘Secret Backyard’

A Rare Peek Inside a Semi-Secret ‘Secret Garden’

When Marsha Norman suggested the idea to producer Jerry Goehring to stream the 2018 workshop over a deadlocked Broadway revival of “The Secret Garden” as a benefit, he thought it was a great idea.

He just didn’t know if it would be possible.

“I said,” To be honest, I don’t know it’s ever been done before, “said Goehring, a member of the team that was out to bring the magnificent musical, which has never been revived there since the Tony Award, onto Broadway In 1991 he won the production with Mandy Patinkin.

Securing the rights to stream a musical – let alone a workshop, footage that should never see the light of day and show actors in their harshest form – can be complicated.

But it helped that Norman, the musical’s Pulitzer Prize-winning writer, was already on board – as was new director Warren Carlyle (“After Midnight”) and all 21 actors, including Sierra Boggess (Lily) and Clifton Duncan (Archibald Craven) and Drew Gehling (Neville Craven).

“They all asked ‘Please, what can we do to help?'” Goehring said this week.

The buy-in of all the members involved and the compensation of the actors were the conditions for the Actors’ Equity Association, the union, to give approval for the project, which will benefit the Dramatists Guild Foundation and the Actors Fund.

“They said they rarely get requests for archive footage,” said Goehring, who teamed up with producers Michael F. Mitri and Carl Moellenberg to develop the project. “But if at the end of the day 100 percent of the members on the show agree, we could do it.”

The two-hour workshop, which includes a full run of the show with no costumes or sets, premieres on Thursday, May 6th at 8 p.m. on Broadway on Demand and will remain available until May 9th. It is dedicated to Rebecca Luker, the musical Original Lily, who died in December aged 59, less than a year after announcing she had ALS

“It’s wonderful and terrifying at the same time,” said Carlyle, who directed and choreographed the workshop. “It’s at its roughest, with all of my terrible ideas and some good ideas. It’s really like pulling the curtain back. “

Göhring said the workshop showed the production in its “early stages” – and was never intended to be seen by any kind of audience, let alone the public.

“We weren’t going to invite anyone,” he said, noting that at first the writers just wanted the opportunity to get a first look at the entire show – artistically. “But it turned out to be so special that everyone agreed that we should invite our friends in the industry, including Broadway theater owners, to hear their opinions.”

Based on the 1911 children’s novel by Frances Hodgson Burnett, the musical tells the story of an orphaned English girl whose personality blossoms when she and a sick cousin restored a neglected garden. The original Broadway production brought in three Tonys including Luker, Patinkin, a pre-Hedwig John Cameron Mitchell, and 11-year-old Daisy Eagan, who won Mary Lennox for her performance as heroine.

The revival, Carlyle said, is a “total redesign”. It will offer reduced sets, more intimate orchestrations and a different scenic design. But all of Lucy Simon’s songs are intact, he assured the fans of the original, who just shifted – not that anyone would dare cut “Lily’s Eyes”.

“We joke that we lost a lot of big bushes,” he said. “A lot of the big scene transitions from the early 1990s have been eliminated, so it really goes a lot better.”

It is clear, said Carlyle, that the workshop is a rough draft: the garden is imaginary; the dress code more t-shirts than vests. Pieces of tape on the bare floor mark the edge of the stage and the position of the grand pianos. There are few props.

“There are no frills,” he said. “This enables me, as a director, to ensure that we understand the story correctly.”

To keep track of scene changes, the team added digital renderings by production designer Jason Sherwood (“Rent: Live”) as transitions. But in the end, said Carlyle, the material speaks for itself.

“The book Marsha wrote and Lucy’s music are so powerful that you can be in an empty room with talented artists and move around just like it’s on a Broadway stage,” he said.

There are reasons the Broadway show never got revived: critics said the elaborate set and costumes made the actors struggle to be in focus, and the book was overflowing with supporting characters.

“Whether ‘The Secret Garden’ is a compelling dramatic adaptation of its source or just a beautiful, stately shrine is sure to be the subject of intense public debate,” wrote New York Times theater critic Frank Rich in his review of the original. “For one thing, I often had problems getting the pulse of the show.”

Broadway is still a destination for the future, said Goehring, although the pandemic has set the time axis in motion.

“We are currently not looking for new investments,” he said. “Our only goal is to raise money for nonprofits.”

The 2018 workshop was the last in a series of high-profile iterations of the musical, which included a 2016 concert at Lincoln Center with Ben Platt, Ramin Karimloo and Boggess. David Armstrong directed a production at 5th Avenue Theater in Seattle and the Shakespeare Theater Company in Washington DC in 2016-17.

No cast has yet been determined or the theater secured, but Göhring hopes the orchestrations will take shape in the fall.

“As soon as we’re all back in the same room, we’ll keep working on it,” he said.

“Our ultimate goal is to do this as best we can,” he added. “No matter how long that takes.”

In the secret garden: workshop and livestream experience
May 6th to 9th; livestream.broadwayondemand.com

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Health

CDC panel debates J&J Covid vaccine after uncommon blood clot challenge

CDC panel debates J&J Covid vaccine after rare blood clot issue

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An advisory panel from the Centers for Disease Control and Prevention is holding an emergency meeting Friday to discuss Johnson & Johnson’s Covid-19 vaccine and its use after six women developed a rare but potentially life-threatening bleeding disorder called the one left dead.

A positive recommendation from the CDC Advisory Committee on Immunization Practices could pave the way for US regulators to lift the recommended hiatus for the use of the J&J shot earlier this weekend.

The CDC panel decided to postpone a decision on the vaccine last week while officials continued to investigate cases of six women who developed cerebral sinus thrombosis (CVST) within about two weeks of receiving the shot.

Earlier this week, J&J announced that it would restart its vaccine rollout in Europe after regulators there backed the single vaccine by recommending adding a warning to the label. The European Medicines Agency has examined all available evidence, including reports from the United States.

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Health

A brand new research hints at a purpose the J.&J. and AstraZeneca vaccines could trigger blood clots in uncommon circumstances.

A new study hints at a reason the J.&J. and AstraZeneca vaccines may cause blood clots in rare cases.

An advisory group from the Centers for Disease Control and Prevention has recommended that the Johnson & Johnson Covid-19 vaccine hiatus be lifted for all adults while also putting up a warning sign about a rare but dangerous blood clot disorder. However, a central mystery remains: how could a vaccine given to nearly eight million people cause the side effect in just a few of them?

There’s no clear answer yet, but Dr. Andreas Greinacher, a researcher at the University Medical Center Greifswald in Germany, leads an attempt to find out. Speaking at a news conference on Tuesday, he said he had an agreement with Johnson & Johnson to study the components of the vaccine to see if it could interfere with normal blood clotting under certain rare conditions.

“We just agreed that we’d like to work together,” he said.

It is possible, said Dr. Greinacher that the Johnson & Johnson vaccine can cause rare side effects through the same process that he suspects is responsible for similar side effects of the AstraZeneca vaccine. The main component of both vaccines are harmless viruses called adenoviruses, which invade human cells and deliver a coronavirus gene that later triggers an immune response.

On Tuesday, Dr. Greinacher and his colleagues published a report on how the AstraZeneca vaccines can trigger the side effect. The study has not yet been published in a scientific journal.

The scientists found that components of the AstraZeneca vaccine can adhere to a protein that releases platelets when blood clots form. These lumps of molecules could be viewed by the body as foreign invaders, the scientists speculated, triggering a cascade of reactions that turn platelets into dangerous clots.

Dr. Paul A. Offit, a vaccines expert at Philadelphia Children’s Hospital who was not involved in the study, found Dr. Greinacher fascinating, but far from the final word. “It throws a lot of opportunities,” he said.

Dr. Offit said it was not clear which of the many factors the researchers looked at could explain the rare blood clots in people vaccinated with AstraZeneca’s doses. “It’s like taking a sip from a fire hose,” he said.

At a press conference on Tuesday, Dr. Greinacher said the research could reveal ways the AstraZeneca vaccine can lower the risk of blood clots or treat the side effects. However, he stressed that the small risk of these side effects was outweighed by the protection that vaccines like AstraZeneca offer against Covid-19.

“Not being vaccinated is far more dangerous than being vaccinated and at risk for this adverse drug reaction,” he said.

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Health

A C.D.C. panel discusses new uncommon clot circumstances in J. & J. shot recipients and the way total threat appears to be very low.

A C.D.C. panel discusses new rare clot cases in J. & J. shot recipients and how overall risk seems to be very low.

Twelve of the 15 women in the confirmed cases developed blood clots in the brain. Many had blood clots elsewhere as well. Initial symptoms, which include a headache, usually begin six or more days after vaccination, said Dr. Shimabukuro. As the disorder develops, it can cause increased headaches, nausea and vomiting, abdominal pain, weakness in one side of the body, difficulty speaking, loss of consciousness, and seizures.

Dr. Shimabukuro found that seven of the women were obese, two had hypothyroidism, two had high blood pressure, and two were using oral contraceptives. It is not yet clear whether any of these factors could increase the risk of developing a coagulation disorder after vaccination.

Patients’ symptoms closely resemble a rare syndrome that can be caused by heparin, a widely used blood thinner, said Dr. Michael Streiff, a hematologist at Johns Hopkins University, joined the panel. Heparin, which could typically be used to treat blood clots, shouldn’t be used to treat these patients, he said.

Doctors should consider the rare coagulation disorder in patients who have blood clots and low platelet counts within three weeks of receiving the Johnson & Johnson vaccine, said Dr. Streiff.

“Knowing that this syndrome exists will help improve outcomes,” he said.

The committee could recommend Johnson & Johnson put up a formal warning label about the side effects, as the company has done in the European Union. About 10 million doses or more of the vaccine, which is manufactured at the company’s facility in the Netherlands, are on shelves in the United States and could be used immediately.

The meeting comes as the federal government is also investigating issues at a Baltimore factory that is slated to meet the country’s demand. Emergent BioSolutions, the operator of the facility, has manufactured tens of millions of doses of Johnson & Johnson’s vaccine, but they cannot be distributed until regulatory agencies certify the facility.

After Emergent had to discard up to 15 million potentially contaminated doses of the vaccine last month, federal regulators conducted an inspection that found a number of problems, including the risk of other lots being contaminated.

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Health

Blood Clots Linked to AZ Vaccine Stem From Uncommon Antibody Response

Blood Clots Linked to AZ Vaccine Stem From Rare Antibody Reaction

The antibodies resulted in a condition called thrombotic thrombocytopenia, which caused both clotting and abnormal bleeding. The researchers suggested calling the newly identified version in these patients “vaccine-induced immunothrombotic thrombocytopenia” or VITT.

Scientists have put forward various theories of what triggers the immune response. The AstraZeneca vaccine uses a chimpanzee adenovirus to transport DNA into recipients and trigger an immune response against the coronavirus. Laboratory research has shown that the chimpanzee virus or DNA could be causing the problem. Some researchers have suggested that bleeding from the injection mixed with the vaccine could bring platelets into the crosshairs of the immune system.

Dr. Greinacher called the theories plausible but unproven.

The article described special blood tests that could help diagnose the disorder and differentiate it from other, more common, clotting problems unrelated to the vaccine. The research team suggested treatment with a blood product called intravenous immunoglobulin, which is used to treat various immune disorders. Dr. Greinacher compared the treatment to putting out a fire.

Medicines called anticoagulants or blood thinners can also be given. However, the researchers advised against prescribing a commonly used heparin because the vaccine-induced condition is very similar to a severe reaction that is rarely seen in people given heparin.

The second report from Norway described five patients, one male and four female health workers aged 32 to 54, who had blood clots and bleeding seven to ten days after receiving the AstraZeneca vaccine. Four had severe blood clots in the brain and three died. Severe headache was one of her early symptoms. Like the German patients, they all had high levels of antibodies that could activate blood platelets.

The team from Norway also recommended intravenous immunoglobulin treatment. The researchers said the disorder is rare but “a new phenomenon with devastating effects on otherwise healthy young adults,” and they suggested it might be more common than previous studies with the AstraZeneca vaccine had shown.

On Friday, European regulators also said they were reviewing reports of some blood clot cases that have occurred in people who had received the Johnson and Johnson vaccine. In the United States, federal agencies are investigating reports of another type of unusual blood disorder in which a few dozen people who received either the Pfizer-BioNTech or Moderna vaccines experienced steep decreases in platelet counts.

Benjamin Mueller and Melissa Eddy contributed to this.

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World News

U.Okay. says under-30s ought to get a non-AstraZeneca possibility; E.U. finds a ‘potential hyperlink’ to uncommon clots.

U.K. says under-30s should get a non-AstraZeneca option; E.U. finds a ‘possible link’ to rare clots.

The UK said Wednesday that it would offer alternatives to the AstraZeneca vaccine for adults under 30 as European regulators identified a “possible link” with rare blood clots, a setback for the world’s most widely used vaccine and a blow for the 100+ Described countries relying on it to save lives amid a global surge in coronavirus cases.

The European regulator, the European Medicines Agency, has no longer advised restricting the use of the vaccine in the 27 countries of the European Union, stating that it is up to national authorities to decide who should receive which vaccine.

Until the announcement, the UK had never let up in the use of the vaccine, making it a holdover in Europe, although many countries discovered unusual, sometimes fatal, blood clots in some recipients. However, there is evidence that very few Britons were also affected, forcing the country to reduce the use of a vaccine, which is the backbone of its world’s best immunization program, among younger people.

Concerns about the blood clots have threatened the pace of vaccination well beyond Europe. At least 111 countries of different incomes have administered doses of AstraZeneca’s shot, making it the most powerful weapon of international aid groups in the fight against the death toll in AstraZeneca Countries with a shortage of vaccines.

Both UK and European regulators said it was possible the clots were linked to the vaccine but that more research was needed. The European regulators described the cases as a serious but “very rare” side effect.

According to official information, the European regulatory authorities had received reports of 222 cases of the rare blood clotting problem in Great Britain and the European Economic Area with 30 countries (European Union plus Iceland, Norway and Liechtenstein) by Sunday. They said that about 34 million people in those countries had received the AstraZeneca vaccine and that the coagulation problems occurred at a rate of about 1 in 100,000 recipients. The condition can be treated.

European regulators said they had carried out detailed reviews of 86 cases by March 22, of which 18 were fatal.

The agency reiterated that the general benefits of the vaccine still outweighed the risks, but urged health professionals and recipients of the shot to be careful about symptoms such as shortness of breath, chest pain, or leg swelling.

Many European countries have restricted the use of the vaccine in younger people as some scientists believe they are at greater risk of developing the rare blood clots. You also have a lower risk of developing severe Covid-19, which raises the safety bar for any vaccine given to younger people.

However, the regulator said it had not concluded that age or gender posed a specific risk and would investigate the issue further.

“This case clearly shows one of the challenges posed by large-scale vaccination campaigns,” said Emer Cooke, head of the agency, in a press conference Wednesday. “When millions of people receive these vaccines, very rare events that were not identified during clinical trials can occur.”

“The risk of mortality from Covid is much greater than the risk of mortality from the side effects,” added Ms. Cooke.

No other vaccine has sparked as much controversy as the shot by the British-Swedish company who used the Block Spats on supply cuts, its effectiveness and ultimately on rare but sometimes fatal blood clots that have been reported in some recipients.

These concerns prompted several European countries to first restrict the use of AstraZeneca in older age groups and then suspend it on reports of blood clots, only to reintroduce it last month after the European Medicines Agency issued a preliminary opinion on the vaccine’s benefits outweighing the risks .

Because doctors reported a higher incidence of severe blood clots in younger people, some countries decided to stop giving the shot to anyone under the age of 55.

Europe’s concerns about the vaccine’s side effects are also likely to threaten global vaccination efforts, with much of the developing world relying on the AstraZeneca vaccine to help fight the pandemic. The shot is the cornerstone of Covax, a program designed to make vaccine access more equitable around the world.

The vaccine appeared to trigger an immune response in which antibodies bind to platelets and activate them, German doctors and the European Medicines Agency have said. These platelets, in turn, caused dangerous clots to form in certain parts of the body, including veins that drain blood from the brain, leading in some cases to a rare type of stroke.

Doctors have said why the antibodies develop in these people is not known. Some component of the vaccine or an excessive immune response – or both – could be the cause, they said.

There is no known disease that makes patients more susceptible to this coagulation disorder after vaccination, according to the European regulatory authorities.