Tag: AstraZeneca

AstraZeneca Vaccine Confers COVID Protection for People with HIV

Image by Ivan Diaz on Unsplash

Interim results from a phase 1B/2A clinical trial conducted by the Wits Vaccines and Infectious Diseases Analytical (VIDA) research unit showed that the AstraZeneca vaccine conferred COVID protection in people living with HIV.

The findings, published in Lancet HIV, show that the AstraZeneca COIVD vaccine is likely to work as well in people living with HIV compared with people who are HIV negative.

These interim findings are vital for informing the clinical management of people with HIV during the COVID pandemic.

In general, clinical trials which evaluate the safety and immunogenicity of COVID vaccines in people living with HIV are limited, and in Africa they are virtually non-existent. This is despite the overwhelming prevalence of HIV infection in Africa, especially South Africa .

“We searched PubMed for peer-reviewed articles published between 1 January 2019 and 29 June 2021, using the terms ‘safety’ and ‘Covid-19’ and ‘vaccine’, but we did not find any reports that evaluated safety and immunogenicity of COVID vaccines in this population,” said Shabir Madhi, Professor of Vaccinology and Director of Wits VIDA, which led the first South African trial for a COVID vaccine in June 2020.

Compared to the general population, people living with HIV have an increased risk of infectious diseases and have a greater mortality risk when hospitalised with severe COVID.

In addition, compared with HIV-negative individuals, people with HIV are at greater risk for infectious diseases, such as influenza, including during antiretroviral therapy (ART).

Risk factors for severe COVID in people with HIV include more advanced stage of HIV/AIDS, the HIV-1 infection not being virally suppressed, and CD4 counts below 500 cells per microlitre.

The study was an interim analysis of a randomised, double-blind, placebo-controlled, phase 1B/2A trial. In 2020, the trial enrolled 104 people living with HIV were enrolled in the trial, HIV-negative people. Eligibility criteria for people with HIV included being on ART for at least three months, with a plasma HIV viral load of less than 1000 copies per microlitre.

The HIV study was a unique addition to the AstraZeneca COVID vaccine clinical trial, and aimed to assess safety and immunogenicity of this vaccine in people with HIV and HIV-negative people in South Africa. The primary endpoint in all participants regardless of HIV status was the safety, tolerability, and reactogenicity profile of the AstraZeneca COVID vaccine.

Reactogenicity refers to a subset of reactions that occur soon after vaccination, and are a physical manifestation of the inflammatory response to vaccination. Such symptoms include pain, redness, swelling or induration for injected vaccines, and systemic symptoms, such as fever, myalgia, headache, or rash. In clinical trials, information on expected signs and symptoms after vaccination is actively sought.

The interim findings show that the AstraZeneca COVID vaccine was well tolerated and showed favourable safety and immunogenicity in people with HIV, including heightened immunogenicity in SARS-CoV-2 baseline-seropositive participants.

Source: University of the Witwatersrand

Antibody COVID Prophylactic Cocktail Performs Well in Trials

Source: NCI on Unsplash

A COVID prophylactic cocktail of long-acting antibodies cut the risk of developing symptomatic disease in a high-risk unvaccinated patient population, AstraZeneca announced on Friday.

Initial phase III trial data showed that AZD7442 (tixagevimab and cilgavimab) as pre-exposure prophylaxis significantly reduced the risk of developing COVID symptoms by 77% versus placebo, meeting the trial’s primary endpoint.
AstraZeneca further noted there were no cases of severe COVID or COVID-related deaths in the intervention group, while there were three cases of severe COVID and two deaths in the placebo group.

No safety concerns were noted by the manufacturer, as the treatment was well-tolerated and adverse events were balanced between groups.

A key feature of the trial was that 75% of participants had comorbidities, including being “at risk of an inadequate response to active [immunisation],” such as older adults and those with immunosuppressive disease or on immunosuppressive medication.

“With these exciting results, AZD7442 could be an important tool in our arsenal to help people who may need more than a vaccine to return to their normal lives,” the trial’s principal investigator, Myron Levin, MD, of the University of Colorado School of Medicine, said in a statement.

AZD7442 was derived from the B cells of convalescent patients. PROVENT was a phase III randomised trial conducted in the US and Europe. Participants were 5197 adults “who would benefit from prevention” with the long-acting antibody, were unvaccinated at the time of enrollment, and tested negative for SARS-CoV-2.
Participants were randomised 2:1 to receive a single 300 mg dose of AZD7442 or placebo. AstraZeneca noted that 43% of participants were ages 60 and older. The company noted that the drug is active in lab studies against emerging strains, including the Delta variant.

Patients were followed for 183 days, though subjects are slated to be followed for 15 months, AstraZeneca said. Data will be submitted for peer-reviewed publication while the company seeks approval for AZD7442.

Source: MedPage Today

New Study Sheds More Light on AstraZeneca Blood Clots

Credit: National Institutes of Health

A UK study has furthered the understanding of the novel blood-clotting condition associated with the Oxford/AstraZeneca vaccine.

Vaccine-induced immune thrombocytopenia and thrombosis (VITT) is characterised by a blockage of veins and a marked platelet reduction. The rare condition was first identified in the UK by Professor Marie Scully (University College of London Institute of Cardiovascular Science), also a Consultant Haematologist at UCLH, and Dr Will Lester from University Hospitals Birmingham NHS Foundation Trust.

In a paper published in the New England Journal of Medicine (NEJM), the first 220 cases of definite and probable VITT in the UK are detailed.

The cases were presented by 182 consultant haematologists, and builds on understanding about the condition outlined in an April 2021 NEJM paper led by Professor Scully.

Meanwhile, a study led by Dr Richard Perry (UCL Queen Square Institute of Neurology and UCLH) published in the Lancet earlier this month provided the most detailed observations so far of cases of cerebral venous thrombosis (CVT). one of the commonest and severest manifestations of VITT.

The overall mortality rate of those presenting to hospitals with definite or probable VITT was 23%, the paper reported. The condition almost entirely manifested between five and 30 days after their first vaccination, with no sex differences seen, and no predisposing prior medical conditions.

The chances of death increased significantly the lower the platelet count and the greater the activation of the blood clotting system, increasing to 73% in patients with a very low platelet count and intracranial haemorrhage following blood clots in the brain.

Overall, 41% of patients had no previous medical diagnoses and 85% were less than 60 years old. Overall incidence in individuals under 50 was estimated to be 1 in 50 000 – in line with reports from other countries.

Though optimal treatment was still uncertain, it was being continually refined in real time, the researchers wrote. For instance, the introduction of the use of plasma exchange in the most severe cases has led to survival rates that were significantly better than would be predicted based on baseline characteristics.

The research adds to evidence for use of non-heparin-based blood thinners to tackle blood clotting in cases of VITT, and that use of intravenous immunoglobin was associated with better outcomes.

Professor Scully said: “As a new condition we are still learning about how best to diagnose and manage VITT, but as time goes on, we have been able to refine our treatment approaches and improve rates of survival and chance of recovery. This continuous learning in real time has been made possible thanks to collaboration between colleagues across the UK.”

Lead author Dr Sue Pavord, at Oxford University Hospitals NHS Foundation Trust, said: “We have worked relentlessly to understand and manage this new condition, so that the hugely successful vaccine roll out can continue, which is the most viable solution to the global pandemic.”

Source: University College London

Intranasal Administration of AstraZeneca Vaccine Reduces Viral Shedding

A multi-institutional team of researchers has found that administering the AstraZeneca COVID vaccine intranasally to infected hamsters and monkeys reduced viral loads in nasal swabs, suggesting reduced shedding.

The group describes the testing they conducted with COVID-infected animals and the possible implications of their work, in their paper published in the journal Science Translational Medicine.

Another COVID surge is occurring in a number of countries where vaccinations are readily available, likely due to the arrival of new variants and wide resistance to the vaccinations. Breakthrough infections have been reported in vaccinated individuals. These has resulted in renewed calls for mask-wearing, even in vaccinated individuals. This is because it is not yet clear if vaccinated people can infect other people, even if they have no symptoms. In this new effort, the researchers suggest that adding intranasal inoculation to vaccination efforts might help.

Currently, the vast majority of vaccines developed and in use are intramuscular, given via shots in the arm. Recently, a team at the University of Alabama noted that an intranasal administration of COVID vaccines would seem to make more sense, since COVID is a disease of the nose, throat and lungs. In this new study, the researchers have given an already existing COVID vaccine intranasally to test animals with COVID to see what would happen.

They found that intranasal administration of the AstraZeneca vaccine to infected hamsters and monkeys led to lowered viral loads on nasal swabs, indicating that intranasal administration reduces viral shedding and thereby transmissibility of the virus.

Unfortunately, prior research has also shown that vaccines given intranasally confer immunity for a shorter period of time than intramuscular vaccination. Thus, as the team in Alabama noted, the best approach might turn out to be a combination of a shot in the arm along with a puff of mist up the nose to confer both short-term and long-term protection.

Source: MedicalXpress

Journal information: Neeltje van Doremalen et al, Intranasal ChAdOx1 nCoV-19/AZD1222 vaccination reduces viral shedding after SARS-CoV-2 D614G challenge in preclinical models, Science Translational Medicine (2021). DOI: 10.1126/scitranslmed.abh0755

Mechanism of AstraZeneca Blood Clotting Detailed in Study

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

Blood Clotting Concerns Resulting in Vaccination Delays

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

AstraZeneca Updates its US Trial Results

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

AstraZenaca Ineffective Against SA Variant in Early Trial

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.

WHO and Health Experts Back AstraZeneca Vaccine

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

Netherlands and Ireland Suspend AstraZeneca Vaccine Over Blood Clots

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