Tag: AstraZeneca

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Mechanism of AstraZeneca Blood Clotting Detailed in Study

On By ModernMedia
Red blood cells. CC0 Creative Commons

A new study into rare cases of blood clots in the brain with low platelets seen in some patients after vaccination has been published in the New England Journal of Medicine.

The research team behind the study were the first clinicians in the UK to spot the link between the Oxford/AstraZeneca vaccine and rare cases of blood clotting along with a low platelet count, before identifying the correct diagnostic test for the syndrome. They recommended the treatment approach which avoids the use of heparin, an anticoagulant typically used to treat normal blood clots.

The researchers detailed the cases of 23 patients, who all presented with thrombosis and thrombocytopenia after receiving the AstraZeneca vaccine, and none of whom had underlying conditions which would predispose them to blood clots.

The presence of the PF4 antibody (platelet factor 4) was detected in almost all cases (21 out of 23). In rare instances, these antibodies are triggered by the blood-thinning drug heparin, a syndrome known as heparin-induced thrombocytopenia (HIT). However, HIT was ruled out because none of the patients in this study received heparin.

The investigators therefore concluded that they were seeing a heparin-independent PF4-dependent syndrome in the setting of the AstraZeneca vaccine. They cautioned that this syndrome needs to be identified quickly if present, because its treatment is very different to that of blood clots with low platelet counts.

Co-author Professor Tom Solomon commented: “Although it is a very rare side effect, this issue of clots in the brain and elsewhere combined with blood abnormalities following COVID-19 immunization is extremely important. It is critical we understand the disease mechanisms so we can provide the best treatment for patients. Here at the University we are part of a national program collecting information on such patients.”

The researchers stressed that vaccination is still the key means to end the pandemic, and everyone should continue to receive a vaccine when offered one.

Source: Medical Xpress

Journal information: Marie Scully et al. Pathologic Antibodies to Platelet Factor 4 after ChAdOx1 nCoV-19 Vaccination, New England Journal of Medicine (2021). DOI: 10.1056/NEJMoa2105385

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Blood Clotting Concerns Resulting in Vaccination Delays

On By ModernMedia

Vaccination programmes are facing increasing delays because of concerns over AstraZeneca’s very rare blood clotting incidents.

Australia and Greece are the latest governments deciding to offer young people alternatives to AstraZeneca’s vaccine. This will delay inoculation campaigns by around a month in Australia, France and Britain. Meanwhile, the World Health Organization said most countries lacked vaccines to cover health workers and others at high risk from exposure to the virus.

WHO Director-General Tedros Adhanom Ghebreyesus said high income countries had on average vaccinated one in four people whilst low income countries the figure was one in over 500.

“There remains a shocking imbalance in the distribution of vaccines,” he told a press briefing on Friday.

The WHO and GAVI vaccine alliance’s COVAX mechanism seeks to secure vaccines for poorer nations. GAVI alliance head Seth Berkley said AstraZeneca’s supply chain had in fact “picked up” when asked whether the vaccine was being shunned.

“As countries decide they are going to prioritise one vaccine or another, that may free up doses, and in so doing we will try to make sure those doses are made available without delay, if countries are willing to make that happen,” he said.

Australia doubled its orders for Pfizer after its health body recommended that people under 50 receive an alternative vaccine. Greece followed Britain’s example in recommending that people under 30 seek an alternative jab.

AstraZeneca said it was working with regulators “to understand the individual cases, epidemiology and possible mechanisms that could explain these extremely rare events”.

Sabine Straus, chair of the EMA’s safety committee, said that the European Medicines Agency (EMA) received reports of 169 cases of the rare brain blood clot by early April, after 34 million doses had been administered.

Most of the cases reported had occurred in women under 60.

On Friday, the EMA said that if a causal relationship is confirmed or considered likely, regulatory action will be needed to minimise risk. It is also investigating Johnson & Johnson’s (J&J) vaccine over reports of blood clots. US infectious disease expert Anthony Fauci however said there were no red flags reported for the J&J vaccine.

The AstraZeneca vaccine is the cheapest and most high-volume vaccine to date to curb the pandemic and avert damaging lockdowns, but supplies have been beset by delays.

However, new data in the EU, beset by delays, showed that the pace of vaccine deliveries was picking up. Germany said it was accelerating inoculations but needed a new lockdown as well.

“Every day in which we don’t act, we lose lives,” Lothar Wieler, president of the Robert Koch Institute, said.

Hong Kong Health Secretary Sophia Chan said the city would defer its order of the AstraZeneca vaccine this year “so as not to cause a waste when the vaccine is still in short supply globally”, adding that the government was considering buying a new, more effective type of vaccine.

All the countries recommending age limits for the AstraZeneca shot have emphasised that its benefits far outweigh the risks of catching COVID for older people. Even so, some people have been put off; in Madrid half of over 60s meant to receive the AstraZeneca vaccine turned up, a day after Spain’s recommendation that younger people get a different shot.

In France, where vaccine hesitancy is high, the top health body recommended that those over 55 who had received a first dose of the AstraZeneca shot get a new-style messenger-RNA vaccine for the second one: either the Pfizer/BioNTech one or Moderna’s.

Source: Reuters

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AstraZeneca Updates its US Trial Results

On By ModernMedia

AstraZeneca issued updated phase III trial data for its COVID vaccine on Wednesday after facing questions on its accuracy of its preliminary US study.

The company now says its vaccine is 76% effective in protecting against symptomatic cases of virus. A release issued on Monday reported a symptomatic efficacy rate of 79%, but the next day, the National Institute of Allergy and Infectious Diseases said it had been informed the company may have included information from its US results that provided an “incomplete view of the efficacy data.”

The updated report still says that the vaccine is 100% effective against severe disease and hospitalisation. A number of US health officials have criticised the company for what seemed like cherry-picking of data in an effort to improve the results’ appearance.

At the time, AstraZeneca said the figures were based on a “pre-specified interim analysis” and promised it would share an updated analysis in the coming days.

Dr Anthony Fauci, White House chief medical advisor and director at the NIAID, was more supportive of the company, calling the situation “unfortunate” and said it was likely AstraZeneca would issue a modified statement.

“This is really what you call an unforced error because the fact is this is very likely a very good vaccine,” Fauci told ABC’s Robin Roberts on “Good Morning America” on Tuesday. “This kind of thing does … really cast some doubt about the vaccines and maybe contribute to the hesitancy. It was not necessary.”

The BBC’s medical editor, Fergus Walsh, was told the results may have been rushed out of a desire to address the safety concerns surrounding possible blood clots. These had resulted in AstraZeneca vaccines being withdrawn from circulation in some European countries.

The updated results include 190 symptomatic cases out of over 32 000 participants — about 50 more symptomatic cases than the data set released on Monday.

The findings suggest the vaccine is more effective in patients aged 65 and older, with a newly reported efficacy rate of 85% for that population, up from 80% stated earlier.

AstraZeneca reiterated that there were no safety concerns with the vaccine and that it was well tolerated.

Source: NBC News

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AstraZenaca Ineffective Against SA Variant in Early Trial

On By ModernMedia

In a phase Ib/II trial, the AstraZeneca vaccine was ineffective against both the South African SARS-CoV-2 variant or the wild-type virus.

In this South African trial, the vaccine’s overall efficacy versus mild-to-moderate COVID was 21.9% and efficacy against the B.1.351 variant was 10.4%.

Participants’ median age was 30, about 56% were men, and 71% were black. Almost 20% of participants were obese, 42% were smokers, and about 3% of those had underlying hypertension or chronic respiratory conditions. All were HIV negative. The median time between doses was 28 days.

Overall, 19 of 750 in the vaccine group (2.5%) and 23 of 717 in the placebo group (3.2%) developed mild-to-moderate COVID. 

In regard to the secondary outcome of testing effectiveness against the B.1.351 variant, the authors note that “the trial was powered for the primary objective of a vaccine efficacy of at least 60% in preventing COVID-19 of any severity, regardless of variants.”

Exploratory analyses found about 33.5% efficacy against COVID of any severity more than 14 days after the first dose. No cases of severe COVID were reported among the participants, but with the groups’ demographics, especially their relatively young age, it was unlikely that severe COVID would be observed in such a small trial.

Professor Shabir Madhi, Executive Director of the Vaccines and Infectious Diseases Analytics Research Unit at Wits, said in a press release that the AstraZeneca results “threw a curveball” after the initial “euphoria” over the effectiveness of the first COVID vaccines. He nevertheless stressed that the AstraZeneca vaccine was still important in preventing hospitals being overrun with COVID patients.

Despite the disappointing results, Prof Madhi said these findings “need to be made in the context of ongoing global spread and community transmission of the B.1.351 variant”.

Source: MedPage Today

Journal information: Madhi SA, et al “Efficacy of the ChAdOx1 nCOV-19 Covid-19 vaccine against the B.1.351 variant” N Engl J Med 2021; DOI: 10.1056/NEJM2102214.

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WHO and Health Experts Back AstraZeneca Vaccine

On By ModernMedia
Woman receiving an injection in the upper arm. Photo by Gustavo Fring from Pexels.

Although a number of EU countries have halted the use of the AstraZeneca vaccine, the company along with a number of health experts insist that it is safe.

AstraZeneca said in a statement on Monday that there were 15 deep vein thrombosis (DVT) events and 22 pulmonary embolism (PE) cases among 17 million people in the EU and UK who have received at least one AstraZeneca vaccine dose.    

“This is much lower than would be expected to occur naturally in a general population of this size and is similar across other licensed COVID-19 vaccines,” the pharmaceutical company said.

The company pointed out that in the clinical trials, “even though the number of thrombotic events was small, these were lower in the vaccinated group. There has also been no evidence of increased bleeding in over 60 000 participants enrolled.”

The European Medicines Agency (EMA) reiterated that there is no indication that the vaccine was responsible for these adverse events. The organisation is currently reviewing the vaccine, and more information is expected in its monthly safety report due during the week. They are currently scheduled to meet on Tuesday.

There are however concerns that slowing the pace of vaccinations will result in more lives lost and fuel vaccine hesitancy.

“I do worry that some people will not be able to differentiate between an unrelated or coincidental VTE [venous thromboembolism] occurrence (due to DVT/PE being so common in the general population) and a causative relationship,” Stephan Moll, MD, of the division of haematology at the University of North Carolina at Chapel Hill, said to MedPage Today.

WHO chief scientist Soumya Swaminathan, MD, noted that it has happened before: Norway early on raised concerns about deaths among the elderly getting vaccinated, but then clarified it was only the expected rate of death.

She pointed out that of the 300 million-odd doses of all COVID vaccines administered globally, not one death has been documented as having been caused by vaccination, “We do not want people to panic. We would for the time being recommend that countries continue vaccinating with AstraZeneca.”

Canada, meanwhile, has said that it will continue to use the AstraZeneca vaccine. The company is likely to seek emergency use authorisation from the United States for its jab when it clears its Stage III clinical trials in that country.

“This does not necessarily mean these events are linked to vaccination, but it’s routine practice to investigate them,” said WHO Director-General Dr Tedros Adhanom Ghebreyesus at a press briefing Monday. “It shows that the surveillance system works and effective controls are in place.”

Source: MedPage Today

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Netherlands and Ireland Suspend AstraZeneca Vaccine Over Blood Clots

On By ModernMedia

In the wake of reports from Norway of blood clots in people shortly after receiving the AstraZeneca vaccine, the Netherlands and Ireland have suspended its use.

The Dutch Health ministry on Sunday said that there was still no evidence of a direct link between the vaccine and possible adverse effects from Norway and Denmark, and there were no reported cases in the Netherlands.

“We can’t allow any doubts about the vaccine,” Dutch health minister Hugo de Jonge said. “We have to make sure everything is right, so it is wise to pause for now.”

Earlier on Sunday Ireland’s deputy chief medical officer, Dr Ronan Glynn, said that deployment of the AstraZeneca vaccine, which makes up 20% of the country’s 570 000 doses given so far, should be “temporarily deferred” with immediate effect as recommended by the country’s National Immunisation Advisory Committee (NIAC). However, he emphasised that there was no proof that blood clots had been caused by the vaccine.

The first blood clots were reported in Austria, and prompted a wave of concern, with Denmark suspending the AstraZeneca vaccine, along with the north of Italy. These latest cases in Norway resulted in three hospitalisations and one death.

The Norwegian Medicines Agency said the four people who had the AstraZeneca injection all had reduced numbers of blood platelets. It added: “People under the age of 50 who have received the AstraZeneca vaccine and feel increasingly unwell more than three days after vaccination, and who notice larger or smaller blue spots in the skin (skin haemorrhages) must consult a doctor or out-of-hours medical service as soon as possible.

“Similar incidents have been reported in other European countries, and the European Medicines Agency (EMA) is considering whether there may be an association with the coronavirus vaccines. So far, no conclusion has been reached.”

Professor Karina Butler, head of NIAC, said it was acting out of an abundance of caution but wanted a better understanding of this unanticipated cluster of “very serious” clotting events in younger people.

There were similarities to other cases reported elsewhere in Europe, she added. It was necessary to know “was there a possibility of a relationship with the vaccine, something which was rare but very serious and could have significant outcomes”, she said to Virgin Media News.

The agency did not yet know whether more blood clots were happening than expected in the population generally. “But they do seem to have clustered together at a level and in younger people – I mean less than 65 – where we wouldn’t necessarily have expected them to happen and thus the question was should we just pause until we get that information, because above all we want to maintain confidence in the vaccine programme so that people can feel that what they are getting is safe, that any serious safety signal is being thoroughly investigated,” she said. 

In a statement, Dr Glynn said: “It has not been concluded that there is any link between the Covid-19 vaccine AstraZeneca and these cases. However, acting on the precautionary principle, and pending receipt of further information, the NIAC has recommended the temporary deferral of the Covid-19 vaccine AstraZeneca vaccination programme in Ireland.”

Source: The Guardian

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Ghana Receives First Vaccines from Covax

On By ModernMedia

Wednesday was a day to celebrate in Ghana as the country took delivery of the first 600 000 vaccines from the Covax inoculation scheme for poorer countries. According to the AFP, some 217 million people have been inoculated so far. 

The Covax scheme, which is led by Gavi the Vaccine Alliance, the World Health Organization and the Coalition for Epidemic Preparedness Innovations , is seeking to ensure low and middle-income countries equitably receive vaccines. head Tedros Adhanom Ghebreyesus cheered on the first delivery of the Covax vaccines with an enthusiastic tweet.

“At last!” he wrote. “A day to celebrate, but it’s just the first step.”

Healthcare experts had long been warning that global access to vaccines was necessary to put an end to the pandemic. Thus far, some 112 million people (and likely more, especially in Africa) have been infected with COVID and 2.4 million people have died from the disease. The recession has caused millions of job losses, and set back development in many areas.

The delivery of the Oxford/AstraZeneca vaccines was broadcast live on Ghanian TV, and will be administered in Ghanaian cities from Tuesday. About two billion doses are expected to be distributed this year under the Covax scheme, although it is unclear if this goal will be met, given the difficulty many advanced nations have experienced in getting vaccines. The European Union, for example, has suffered setbacks in deliveries from AstraZeneca and Pfizer. EU member nation Hungary has meanwhile decided to forge ahead with its own vaccine acquisition, ordering five million doses from Chinese firm Sinopharm, and this week began its first vaccinations.

The Ivory Coast is set to receive the next batch from Covax later this week. 

Source: Eyewitness News

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Reckless to Discard AstraZeneca Vaccines, Says Prof Madhi

On By ModernMedia

Professor Shabir Madhi of Wits University says that it would be reckless to simply abandon South Africa’s stock of AstraZeneca vaccine doses, even after a small trial showed it to have minimal effect against the local variant.

One million doses of AstraZeneca vaccine had been scheduled for rollout, but that plan has been put on hold after preliminary results showed that it conferred minimal effectiveness against mild-to-moderate infections by the dominant 501Y.V2 strain in South Africa. 

Madhi said that scientists needed more time to go through the data, said Madhi.

“I think it would be highly reckless for us to discard the vaccine. We paid a high price for it and so the vaccines do have a role in protecting from severe disease. I think an important feature in all the vaccines is that generally, vaccines work much better in preventing severe disease.”

There is already a closing window of opportunity, since it was recently discovered that the first batch of one million doses received from the Serum Institute of India would be expiring in April.

Madhi said that there were other options to put the vaccine to good use.
“If we’re strategic in terms of the rollout, we might still be able to get the vaccine used, not two doses per individual but at least a single dose and we could possibly follow it up then with another vaccine and a few vaccines that might come online in the next two or three months.”

In an interview with the BBC, he said that the disappointing results of the trial had not been able to show the effectiveness against severe COVID, as the sample size was too small and too young, with an average age of 31, but that it might still have a protective effect in different age groups. “There’s still some hope that the AstraZeneca vaccine might well perform as well as the Johnson & Johnson vaccine in a different age group demographic that I address of severe disease,” he said.

Source: Eyewitness News

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Ramaphosa to Take Delivery of SA’s First Vaccine Doses

On By ModernMedia

President Cyril Ramaphosa will take delivery of the first million doses arrives in South Africa at OR Tambo airport on Monday.

Ramaphosa will be accompanied by Deputy President David Mabuza, Health Minister Zweli Mkhize and the High Commissioner of India. After the vaccine has been received, it will be taken to cold storage for and undergo technical processing and quality testing.

Acting spokesperson for the Presidency, Tyrone Seale, said: “The arrival of the fist consignment at OR Tambo International Airport marks the start of the vaccine roll-out, which President Ramaphosa describes as the largest and most complex logistical vaccine undertaking in South Africa’s history.”

The AstraZeneca doses were produced by the Serum Institute of India, and healthcare workers will be the first to be vaccinated, with essential workers second on the list. However, the Department of Health has suggested that politicians (who are classified as essential workers) may be the first to receive the vaccine, in order to reassure the public and encourage vaccine uptake. An additional 500 000 doses are to be delivered in February.

There are fears that current vaccines are less effective against the B1.351 “South African” variant. The Novovax vaccine has been shown to have slightly less than 50% effectiveness in South African trials, due to the variant and the prevalence of HIV in the population. Johnson & Johnson’s vaccine, which is set to be produced locally by Aspen, is around 57% effective in South Africa. These are about what is achieved with annual flu vaccines, which are 40-60% effective. The AstraZeneca AZD1222 vaccine developed in concert with Oxford University have been shown to be 70% effective in clinical trials, although this was prior to the widespread emergence of COVID variants. However, it is possible to adjust vaccines to to deal with the new variants, with Dr Anthony Fauci saying that this reduced vaccine effectiveness against variants is a “wake-up call”.

The Azstra Zeneca vaccine uses a non replicating viral vector to deliver genetic information to cells, instructing them to produce the spike protein of the SARS-CoV-2 virus to train the immune system to recognise it and build immunity. It requires two doses administered four weeks apart, and unlike many other vaccines, does not require storage at extremely cold temperatures – only requiring normal refrigeration at 2° to 8°C.

Source: Eyewitness News

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EU Demands AstraZeneca Vaccine Produced by UK Plants

On By ModernMedia

In another twist to the EU’s seemingly never-ending vaccine procurement problems, the EU health minister has demanded that vaccine production from AstraZeneca’s UK operations be sent to EU countries to make up for the company’s shortfall at its two European plants. 

EU health commissioner Stella Kyriakides dismissed AstraZeneca’s argument that it the UK take precedence.

“We reject the logic of first come, first served,” the commissioner declared. “That may work at the neighbourhood butcher’s [shop] but not in contracts and not in our advanced purchase agreements. There’s no priority clause in the purchase agreements.”

The Anglo-Swedish company had triggered fury in Brussels when it was revealed that it would only be able to deliver 25% of the agreed vaccine doses when they received approval as expected this Friday. However, AstraZeneca assured the UK government that it would meet its commitment of supplying 2 million doses a week. UK government sources insisted that only once AstraZeneca had fulfilled its order to provide the UK with 100 million doses would its vaccine production be allowed to be released to serve other countries.

The EU meanwhile is flagging far behind, with only 2% of its adult population vaccinated compared to 10% of the UK’s. Kyriakides pointed out that in its contract with AstraZeneca, four European plants were listed as suppliers and two of those were located in the UK, and she expected them to work for EU citizens.

An AstraZeneca spokesperson said: “Each supply chain was developed with input and investment from specific countries or international organisations based on the supply agreements, including our agreement with the European commission.

“As each supply chain has been set up to meet the needs of a specific agreement, the vaccine produced from any supply chain is dedicated to the relevant countries or regions and makes use of local manufacturing wherever possible.”

Kyriakides said the argument was unacceptable, emphasising that the company had a moral duty to treat the EU similarly to the UK, adding that there was no “priority clause” that would justify UK residents benefiting first from doses made there.

Germany meanwhile has said that it is facing 10 weeks of vaccine shortage.
However, there is encouraging news as Israel reported a 92% effectiveness with the Pfizer/BioNTech vaccine outside trials. Only 31 of 163 000 Israelis caught COVID within ten days of the innoculation reaching its full strength. None were hospitalised.

Source: The Guardian