Scientists at the University of Oxford, in the UK, announced this Monday, through a statement from its production partner AstraZeneca and also in a report published in The Lancet, that, according to preliminary results, the university’s vaccine for COVID-19 is safe and induced an immune response.
The results of the vaccine called AZD1222 by the manufacturer and ChAdOx1 nCoV-19 by the scientists refer to the first two phases of immunization testing. The third phase is taking place in Brazil, among other countries. The effect should be reinforced after a second dose of the vaccine, according to the scientists.
The Oxford-AstraZeneca vaccine is the most advanced among all those listed by the WHO. It is phase 3, the final phase, still in progress that will show whether the vaccine is effective in immunizing a large number of people.
In June, the Brazilian government signed a $127 million agreement to start producing the vaccine in the country, in partnership with the Osvaldo Cruz Foundation (FioCruz).
Professor Andrew Pollard, Chief investigator of the Oxford Vaccine Trial at Oxford University and co-author of the trial, said: “The interim Phase I/II data for our coronavirus vaccine shows that the vaccine did not lead to any unexpected reactions and had a similar safety profile to previous vaccines of this type. The immune responses observed following vaccination are in line with what we expect will be associated with protection against the SARS-CoV-2 virus, although we must continue with our rigorous clinical trial program to confirm this. We saw the strongest immune response in participants who received two doses of the vaccine, indicating that this might be a good strategy for vaccination.”
COV001 is a blinded, multi-center, randomized controlled Phase I/II trial with 1,077 healthy adult participants, aged 18-55 years. It assessed a single dose of AZD1222 against a comparator meningococcal conjugate vaccine, called MenACWY. Ten participants also received two doses of AZD1222 one month apart.
A single dose of AZD1222 resulted in a four-fold increase in antibodies to the SARS-CoV-2 virus spike protein in 95% of participants one month after injection. In all participants, a T-cell response was induced, peaking by day 14, and maintained two months after injection.
The other vaccine being tested in Brazil
This is the second promising vaccine being tested in Brazil. From this Tuesday, volunteers from six Brazilian states will receive doses of the vaccine from the Chinese laboratory Sinovac, called CoronaVac. The application is part of tests to prove the effectiveness of the product and is led in Brazil by the Butantan Institute, in São Paulo.
In all, 9,000 people will participate in the testing in São Paulo, Rio de Janeiro, Minas Gerais, Paraná, Rio Grande do Sul and the Federal District. The Butantan Institute did not disclose how many people are part of this first phase of the clinical trial.