20 februari 2021: Op de website van de WHO wordt in dit artikel steeds een update gegeven van de resutlaten en ontwikkelingen bij de vaccins: https://www.who.int/publications/m/item/draft-landscape-of-covid-19-candidate-vaccines

5 januari 2021: Veel informatie over de vaccins en de tijdschema's van vaccineren tegen het coronavirus staan op deze website: https://www.rijksoverheid.nl/onderwerpen/coronavirus-vaccinatie
Zie ook in gerelateerde artikelen.

Zie ook artikel over het Moderna vaccin: 

https://kanker-actueel.nl/vaccin-van-moderna-mrna-1273-geeft-een-effectiviteit-van-94-en-een-half-procent-tegen-covid-19-blijkt-uit-een-tussenevaluatie.html

Zie ook artikel over het Pfizer vaccin: 

https://kanker-actueel.nl/pfizer-vaccin-tegen-het-coronavirus-covid-19-geeft-hoopgevende-tussenresultaten-met-90-procent-effectiviteit-maar-er-zijn-nog-veel-vragen-te-beantwoorden.html

Zie ook eerdere berichtgeving over het AZD1222 vaccin bij ook ouderen in dit artikel: 

https://kanker-actueel.nl/oxford-studie-naar-vaccin-tegen-coronavirus-covid-19-toont-een-robuuste-immuunrespons-bij-ouderen-55-de-groep-met-het-hoogste-risico-op-de-ziekte.html

20 februari 2021: In The Lancet is een overzichtstudie gepubliceerd van 4 studies over de effectiviteit van het Astrazenecavaccin - AXD1222. Na 1 injectie al blijkt het risico op ernstige ziekte bijna 100 procent te zijn, want er waren bij de studiegroep geen ziekenhuisopnames. En is toch wel geruststellend dat al na 1 injectie het vaccin beschermt tegen zo ernstig ziek worden dat ziekenhuisopname nodig is. 

Zie dit volledige studierapport: Single-dose administration and the influence of the timing of the booster dose on immunogenicity and efficacy of ChAdOx1 nCoV-19 (AZD1222) vaccine: a pooled analysis of four randomised trials

Abstract onderaan dit artikel

Vertaling via google translate  van resultaten uit de studie:

Tussen 23 april en 6 december 2020 werden 24 422 deelnemers gerekruteerd en gevaccineerd in de vier onderzoeken, van wie 17 178 werden opgenomen in de primaire analyse (8597 kregen ChAdOx1 nCoV-19 en 8581 kregen een controlevaccin). De cut-off van gegevens voor deze analyses was 7 december 2020.

332 NAAT-positieve infecties bereikten het primaire eindpunt van symptomatische infectie meer dan 14 dagen na de tweede dosis. De algehele werkzaamheid van het vaccin meer dan 14 dagen na de tweede dosis was 66,7% (95% BI 57,4-74,0), met 84 (1,0%) gevallen in de 8597 deelnemers in de ChAdOx1 nCoV-19-groep en 248 (2 · 9%) van de 8581 deelnemers in de controlegroep.

Er waren geen ziekenhuisopnames voor COVID-19 in de ChAdOx1 nCoV-19-groep na de initiële uitsluitingsperiode van 21 dagen, en 15 in de controlegroep. 108 (0,9%) van de 12 282 deelnemers in de ChAdOx1 nCoV-19-groep en 127 (1,1%) van 11 962 deelnemers in de controlegroep hadden ernstige bijwerkingen.

Er waren zeven sterfgevallen waarvan werd aangenomen dat ze geen verband hielden met vaccinatie (twee in de ChAdOx1 nCov-19-groep en vijf in de controlegroep), waaronder één COVID-19-gerelateerd overlijden bij één deelnemer in de controlegroep. Verkennende analyses toonden aan dat de werkzaamheid van het vaccin na een enkele standaarddosis vaccin van dag 22 tot dag 90 na vaccinatie 76,0% (59,3-85,9) was. Onze modelanalyse gaf aan dat de bescherming niet afnam tijdens deze eerste periode van 3 maanden. Evenzo werden tijdens deze periode antilichaamspiegels gehandhaafd met een minimale afname op dag 90 (geometrisch gemiddelde ratio 0 · 66 [95% BI 0 · 59-0 · 74]). Bij de deelnemers die twee standaarddoses kregen, was de werkzaamheid na de tweede dosis hoger bij degenen met een langer prime-boost-interval (werkzaamheid van het vaccin 81 · 3% [95% BI 60 · 3–91 · 2] na ≥ 12 weken) dan bij patiënten met een kort interval (werkzaamheid van het vaccin 55 · 1% [33 · 0–69 · 9] na <6 weken). Deze waarnemingen worden ondersteund door immunogeniciteitsgegevens die de respons van bindende antilichamen vertoonden die meer dan tweemaal zo hoog waren na een interval van 12 weken of meer in vergelijking met een interval van minder dan 6 weken bij degenen die 18-55 jaar oud waren (GMR 2 · 32 [ 2 · 01-2 · 68]).

5 januari 2021: Over de mRNA vaccins heeft , wetenschapsjournalist van de Volkskrant een interessant artikel geschreven. mRNA techniek komt in feite uit de oncologie en heeft al zijn nut bewezen als immuuntherapie bij melanomen bv. Arts-bioloog drs. Engelbert Valstar wees me hierop maar ik had dit artikel al gelezen. Maar voor wie is geïnteresseerd: De grote belofte van de techniek achter de coronavaccins

De eerste coronavaccins, sinds deze week in gebruik, zijn gebaseerd op een sciencefictionachtige techniek waaraan wetenschappers tientallen jaren sleutelden. Nu dat eindelijk is gelukt: wat is er nog meer op komst? Behandelingen tegen kanker, een betere griepprik, medicijnen tegen slopende erfelijke ziektes misschien?>>>>>>>lees verder

23 november 2020: Bron: Astrazeneca

In een persbericht zegt AstraZeneca dat hun vaccin AZD1222 dat wordt ontwikkeld samen met de universiteit van Oxford een effectieve bescherming geeft van tussen de 60 en 90 procent tegen het coronavirus - Covid-19. Gemiddeld kwam 70 procent effectiviteit uit de tussenresultaten samengevoegd en samen geanalyseerd.
De 60 procent werd gehaald met twee volle doses om de vier weken toegediend. De 90 procent werd gezien als vrijwilligers eerst een halve dosis kregen en een maand later een volle dosis eropvolgend. 

Uit het persbericht:

One dosing regimen (n=2,741) showed vaccine efficacy of 90% when AZD1222 was given as a half dose, followed by a full dose at least one month apart, and another dosing regimen (n=8,895) showed 62% efficacy when given as two full doses at least one month apart. The combined analysis from both dosing regimens (n=11,636) resulted in an average efficacy of 70%. All results were statistically significant (p<=0.0001). 

Van dit Oxford-vaccin is ook door de Nederlandse regering een aantal doses aangekocht. 

Hier het studieprotocol van AZD1222

In The Lancet werd 18 november 2020 ook deze studie met het AZD1222 vaccin gepubliceerd (abstract in dit artikel): Safety and immunogenicity of ChAdOx1 nCoV-19 vaccine administered in a prime-boost regimen in young and old adults (COV002): a single-blind, randomised, controlled, phase 2/3 trial

Hier het volledige persbericht dat AstraZeneca vanmorgen uit liet gaan:

AZD1222 vaccine met primary efficacy endpoint in preventing COVID-19

This announcement contains inside information

23 November 2020 07:00 GMT
 

Two different dosing regimens demonstrated efficacy with one showing a better profile

No hospitalisations or severe cases of COVID-19 in participants treated with AZD1222
 

Positive high-level results from an interim analysis of clinical trials of AZD1222 in the UK and Brazil showed the vaccine was highly effective in preventing COVID-19, the primary endpoint, and no hospitalisations or severe cases of the disease were reported in participants receiving the vaccine. There were a total of 131 COVID-19 cases in the interim analysis.

One dosing regimen (n=2,741) showed vaccine efficacy of 90% when AZD1222 was given as a half dose, followed by a full dose at least one month apart, and another dosing regimen (n=8,895) showed 62% efficacy when given as two full doses at least one month apart. The combined analysis from both dosing regimens (n=11,636) resulted in an average efficacy of 70%. All results were statistically significant (p<=0.0001). More data will continue to accumulate and additional analysis will be conducted, refining the efficacy reading and establishing the duration of protection.

An independent Data Safety Monitoring Board determined that the analysis met its primary endpoint showing protection from COVID-19 occurring 14 days or more after receiving two doses of the vaccine. No serious safety events related to the vaccine have been confirmed. AZD1222 was well tolerated across both dosing regimens.

AstraZeneca will now immediately prepare regulatory submission of the data to authorities around the world that have a framework in place for conditional or early approval. The Company will seek an Emergency Use Listing from the World Health Organization for an accelerated pathway to vaccine availability in low-income countries. In parallel, the full analysis of the interim results is being submitted for publication in a peer-reviewed journal.

Professor Andrew Pollard, Chief Investigator of the Oxford Vaccine Trial at Oxford, said: “These  findings  show  that  we  have  an  effective  vaccine  that  will  save  many  lives. Excitingly, we’ve found that one of our dosing regimens may be around 90% effective and if this dosing regime is used, more people could be vaccinated with planned vaccine supply. Today’s announcement is only possible thanks  to  the  many  volunteers  in  our  trial,  and  the  hard  working  and  talented  team  of  researchers based around the world.”

Pascal Soriot, Chief Executive Officer, said: “Today marks an important milestone in our fight against the pandemic. This vaccine’s efficacy and safety confirm that it will be highly effective against COVID-19 and will have an immediate impact on this public health emergency. Furthermore, the vaccine’s simple supply chain and our no-profit pledge and commitment to broad, equitable and timely access means it will be affordable and globally available, supplying hundreds of millions of doses on approval.”

The pooled analysis included data from the COV002 Phase II/III trial in the UK and COV003 Phase III trial in Brazil. Over 23,000 participants are being assessed following two doses of either a half-dose/full-dose regimen or a regimen of two full doses of AZD1222 or a comparator, meningococcal conjugate vaccine called MenACWY or saline. The global trials are evaluating participants aged 18 years or over from diverse racial and geographic groups who are healthy or have stable underlying medical conditions.

Clinical trials are also being conducted in the US, Japan, Russia, South Africa, Kenya and Latin America with planned trials in other European and Asian countries. In total, the Company expects to enrol up to 60,000 participants globally.

The Company is making rapid progress in manufacturing with a capacity of up to 3 billion doses of the vaccine in 2021 on a rolling basis, pending regulatory approval. The vaccine can be stored, transported and handled at normal refrigerated conditions (2-8 degrees Celsius/ 36-46 degrees Fahrenheit) for at least six months and administered within existing healthcare settings.

AstraZeneca continues to engage with governments, multilateral organisations and collaborators around the world to ensure broad and equitable access to the vaccine at no profit for the duration of the pandemic.

COV002

COV002 is a single-blinded, multi-centre, randomised, controlled Phase II/III trial assessing the safety, efficacy and immunogenicity of AZD1222 in 12,390 participants in the UK. Trial participants to date are aged 18 years or over, who are healthy or have medically stable chronic diseases and are at increased risk for being exposed to the SARS-CoV-2 virus. Participants receive one or two intramuscular doses of a half dose (~2.5 x1010 viral particles) or full dose (~5x1010 viral particles) of AZD1222 or comparator, meningococcal vaccine MenACWY. Participants have blood samples drawn and clinical assessments for safety as well as immunogenicity at multiple timepoints up to one year post-vaccination. Suspected cases presenting with compatible symptoms were tested for virological confirmation by COVID-19 PCR. In addition, weekly swabbing are done for detection of infection and assessment of vaccine efficacy against infection.

COV003

COV003 is a single-blinded, multi-centre, randomised, controlled Phase III trial assessing the safety, efficacy, and immunogenicity of AZD1222 in 10,300 participants in Brazil. Trial participants to date are aged 18 years or over, who are healthy or have medically stable chronic diseases and are at increased risk for being exposed to the SARS-CoV-2 virus. Participants are randomised to receive two intramuscular doses of a full dose (~5x1010 viral particles) of AZD1222 or comparator, meningococcal vaccine MenACWY as first dose and a saline placebo as second dose. Participants have blood samples drawn and clinical assessments for safety as well as immunogenicity at multiple timepoints up to one year post-vaccination. Suspected cases presenting with compatible symptoms were tested for virological confirmation by COVID-19 PCR.

AZD1222
AZD1222 was co-invented by the University of Oxford and its spin-out company, Vaccitech. It uses a replication-deficient chimpanzee viral vector based on a weakened version of a common cold virus (adenovirus) that causes infections in chimpanzees and contains the genetic material of the SARS-CoV-2 virus spike protein. After vaccination, the surface spike protein is produced, priming the immune system to attack the SARS-CoV-2 virus if it later infects the body.

AstraZeneca

AstraZeneca (LSE/STO/Nasdaq: AZN) is a global, science-led biopharmaceutical company that focuses on the discovery, development and commercialisation of prescription medicines, primarily for the treatment of diseases in three therapy areas - Oncology, Cardiovascular, Renal & Metabolism, and Respiratory & Immunology. Based in Cambridge, UK, AstraZeneca operates in over 100 countries and its innovative medicines are used by millions of patients worldwide. Please visit astrazeneca.com and follow the Company on Twitter @AstraZeneca.

Contacts

For details on how to contact the Investor Relations Team, please click here. For Media contacts, click here.

Single-dose administration and the influence of the timing of the booster dose on immunogenicity and efficacy of ChAdOx1 nCoV-19 (AZD1222) vaccine

Open AccessPublished:February 19, 2021DOI:https://doi.org/10.1016/S0140-6736(21)00432-3 

Single-dose administration and the influence of the timing of the booster dose on immunogenicity and efficacy of ChAdOx1 nCoV-19 (AZD1222) vaccine: a pooled analysis of four randomised trials

Summary

Background

The ChAdOx1 nCoV-19 (AZD1222) vaccine has been approved for emergency use by the UK regulatory authority, Medicines and Healthcare products Regulatory Agency, with a regimen of two standard doses given with an interval of 4–12 weeks. The planned roll-out in the UK will involve vaccinating people in high-risk categories with their first dose immediately, and delivering the second dose 12 weeks later. Here, we provide both a further prespecified pooled analysis of trials of ChAdOx1 nCoV-19 and exploratory analyses of the impact on immunogenicity and efficacy of extending the interval between priming and booster doses. In addition, we show the immunogenicity and protection afforded by the first dose, before a booster dose has been offered.

Methods

We present data from three single-blind randomised controlled trials—one phase 1/2 study in the UK (COV001), one phase 2/3 study in the UK (COV002), and a phase 3 study in Brazil (COV003)—and one double-blind phase 1/2 study in South Africa (COV005). As previously described, individuals 18 years and older were randomly assigned 1:1 to receive two standard doses of ChAdOx1 nCoV-19 (5 × 1010 viral particles) or a control vaccine or saline placebo. In the UK trial, a subset of participants received a lower dose (2·2 × 1010 viral particles) of the ChAdOx1 nCoV-19 for the first dose. The primary outcome was virologically confirmed symptomatic COVID-19 disease, defined as a nucleic acid amplification test (NAAT)-positive swab combined with at least one qualifying symptom (fever ≥37·8°C, cough, shortness of breath, or anosmia or ageusia) more than 14 days after the second dose. Secondary efficacy analyses included cases occuring at least 22 days after the first dose. Antibody responses measured by immunoassay and by pseudovirus neutralisation were exploratory outcomes. All cases of COVID-19 with a NAAT-positive swab were adjudicated for inclusion in the analysis by a masked independent endpoint review committee. The primary analysis included all participants who were SARS-CoV-2 N protein seronegative at baseline, had had at least 14 days of follow-up after the second dose, and had no evidence of previous SARS-CoV-2 infection from NAAT swabs. Safety was assessed in all participants who received at least one dose. The four trials are registered at ISRCTN89951424 (COV003) and ClinicalTrials.govNCT04324606 (COV001), NCT04400838 (COV002), and NCT04444674 (COV005).

Findings

Between April 23 and Dec 6, 2020, 24 422 participants were recruited and vaccinated across the four studies, of whom 17 178 were included in the primary analysis (8597 receiving ChAdOx1 nCoV-19 and 8581 receiving control vaccine). The data cutoff for these analyses was Dec 7, 2020. 332 NAAT-positive infections met the primary endpoint of symptomatic infection more than 14 days after the second dose. Overall vaccine efficacy more than 14 days after the second dose was 66·7% (95% CI 57·4–74·0), with 84 (1·0%) cases in the 8597 participants in the ChAdOx1 nCoV-19 group and 248 (2·9%) in the 8581 participants in the control group. There were no hospital admissions for COVID-19 in the ChAdOx1 nCoV-19 group after the initial 21-day exclusion period, and 15 in the control group. 108 (0·9%) of 12 282 participants in the ChAdOx1 nCoV-19 group and 127 (1·1%) of 11 962 participants in the control group had serious adverse events. There were seven deaths considered unrelated to vaccination (two in the ChAdOx1 nCov-19 group and five in the control group), including one COVID-19-related death in one participant in the control group. Exploratory analyses showed that vaccine efficacy after a single standard dose of vaccine from day 22 to day 90 after vaccination was 76·0% (59·3–85·9). Our modelling analysis indicated that protection did not wane during this initial 3-month period. Similarly, antibody levels were maintained during this period with minimal waning by day 90 (geometric mean ratio 0·66 [95% CI 0·59–0·74]). In the participants who received two standard doses, after the second dose, efficacy was higher in those with a longer prime-boost interval (vaccine efficacy 81·3% [95% CI 60·3–91·2] at ≥12 weeks) than in those with a short interval (vaccine efficacy 55·1% [33·0–69·9] at <6 weeks). These observations are supported by immunogenicity data that showed binding antibody responses more than two-fold higher after an interval of 12 or more weeks compared with an interval of less than 6 weeks in those who were aged 18–55 years (GMR 2·32 [2·01–2·68]).

Interpretation

The results of this primary analysis of two doses of ChAdOx1 nCoV-19 were consistent with those seen in the interim analysis of the trials and confirm that the vaccine is efficacious, with results varying by dose interval in exploratory analyses. A 3-month dose interval might have advantages over a programme with a short dose interval for roll-out of a pandemic vaccine to protect the largest number of individuals in the population as early as possible when supplies are scarce, while also improving protection after receiving a second dose.

Funding

UK Research and Innovation, National Institutes of Health Research (NIHR), The Coalition for Epidemic Preparedness Innovations, the Bill & Melinda Gates Foundation, the Lemann Foundation, Rede D’Or, the Brava and Telles Foundation, NIHR Oxford Biomedical Research Centre, Thames Valley and South Midland's NIHR Clinical Research Network, and AstraZeneca.

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