AstraZeneca has reported that an interim analysis of clinical trials of Covid-19 vaccine candidate, AZD1222, showed one dosing regimen revealed 90% efficacy when given as a half dose.
Positive high-level results from the analysis of these trials carried out in the UK and Brazil showed that the vaccine was highly effective in preventing the disease.
Co-invented by the University of Oxford and Vaccitech, AZD1222 uses a replication-deficient chimpanzee viral vector based on an adenovirus. It also has the genetic material of the SARS-CoV-2 virus spike protein.
A total of 131 Covid-19 cases were in the interim analysis.
It includes data from the Phase II / III COV002 trial in the UK, as well as Phase III COV003 trial in Brazil.
The single-blinded, multi-centre, randomised, controlled COV002 and COV003 trials evaluated the safety, efficacy and immunogenicity of AZD1222 in 12,390 and 10,300 healthy adults, respectively.
Data showed that one dosing regimen had a vaccine efficacy of 90% and another dosing regimen with two full doses of the vaccine candidate given at least one month apart demonstrated 62% efficacy.
Researchers observed an average efficacy of 70% in the combined analysis from both dosing regimens.
An independent Data Safety Monitoring Board concluded that the analysis met its primary endpoint of providing protection from Covid-19 occurring 14 days or more after receiving two doses of vaccine.
Also, researchers reported no hospitalisations or severe cases of the disease in subjects who received AZD1222.
The vaccine reportedly remained well-tolerated, with no serious vaccine-related safety events noted.
AstraZeneca CEO Pascal Soriot said: “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 company plans to seek an Emergency Use Listing from the World Health Organisation for an accelerated pathway to vaccine availability in low-income countries.