Efficacy of AstraZeneca’s Vaccine against COVID-19

This study, published in the Lancet, looks into the vaccine resulting from the collaboration of the Oxford University and AstraZeneca, among others.

Historia natural de la infección asintomática por COVID-19

Data include interim results from 4 ongoing blind randomized controlled studies currently carried out in the UK, Brazil and South Africa. 

All participants over 18 years of age were assigned 1:1 to the ChAdOx1 nCoV-19 vaccine (with a glycoprotein spike on the surface, a chimpanzee adenovirus-vectored vaccine) vs saline.

Participants received two doses of 5×1010 viral particles (standard dose/standard dose). A subgroup in the UK received half the dose initially (low dose/standard dose). 

Efficacy primary end point was symptomatic COVID-19 over 14 days after the second dose. 


Read also: Coronary Access After TAVR: A Potential Problem Ahead.


A total 23848 patients were included, leaving 11636 (7548 from UK and 4088 from Brazil) for the efficacy analysis. 

Participants receiving both standard doses showed a 62.1% efficacy (CI 95%, 41 to 75.7) vs placebo. Those initially receiving half the dose followed by the standard dose showed 90% efficacy. 

Globally, vaccine efficacy was 70.4%.


Read also: The Most Read Articles of January in Interventional Cardiology.


21 days after the first dose, there were 10 COVID-19 cases requiring hospitalization, all in the placebo branch.

Only three events were associated to inoculation, one in the vaccine group, one in the placebo group and one that had not yet been unblinded.

Only 12 and 9% of the population were between 56 and 69, and >70 years old, respectively, in the UK cohort; even fewer, 10% and <1% respectively in Brazil. 

This makes it very hard to draw any conclusions on the efficacy of this vaccine in the elderly population. In fact, some countries are opting out of this vaccine for the elderly until more evidence is made available. 

Conclusion

The ChAdOx1 nCoV-19 (Oxford-AstraZeneca) had an acceptable safety profile and resulted effective to prevent symptomatic Covid-19 in the interim analysis of the four ongoing studies.

aztra

Original Title: Safety and efficacy of the ChAdOx1 nCoV-19 vaccine (AZD1222) against SARS-CoV-2: an interim analysis of four randomised controlled trials in Brazil, South Africa, and the UK. On behalf of the Oxford COVID Vaccine Trial Group.

Reference: Merryn Voysey et al. Lancet. 2021 Jan 9;397(10269):99-111. doi: 10.1016/S0140-6736(20)32661-1.


Subscribe to our weekly newsletter

Get the latest scientific articles on interventional cardiology

More articles by this author

Is the Booster Dose Against COVID-19 Effective for All Ages?

The answer is incontrovertible: it is undeniably effective. For all ages, the confirmed COVID19 and severe case rates were significantly lower for patients who...

Pfizer Booster Dose Efficacy against Omicron

The BNT162b2 vaccine (Pfizer/BioNTech) has previously shown a 95% efficacy against COVID-19. This efficacy has been changing with the surge of new variants and,...

Once Again, the Omicron Variant Tests the Limits of Healthcare Systems, But with Hope

The latest significant COVID-19 variant, the Omicron, is again pushing healthcare systems around the world onto the verge of collapse, having reached over 300...

The Most Read Articles of 2021: COVID-19

A new year is coming to an end and at SOLACI we are going over the most read studies on our website, on COVID-19. Follow...

LEAVE A REPLY

Please enter your comment!
Please enter your name here

Related Articles

SOLACI Sessionsspot_img

Recent Articles

TCT 2024 | FAVOR III EUROPA

The study FAVOR III EUROPA, a randomized trial, included 2,000 patients with chronic coronary syndrome, or stabilized acute coronary syndrome, and intermediate lesions. 1,008...

TCT 2024 | TRISCEND II

This randomized study included 400 patients; 267 were treated with EVOQUE valve and 133 with optimal medical treatment (OMT). After one-year follow-up, there were no...

TCT 2024 – ACCESS-TAVI: Comparing Percutaneous Access Closure Strategies After TAVI

Vascular access complications following transcatheter aortic valve implantation (TAVI) remain common. However, few studies compare vascular access closure methods.  Based on the CHOICE-CLOSURE and MASH...