Oxford vaccine against Covid-19 has between 62% and 90% of effectiveness, says laboratory | Vaccine

A statement from AstraZeneca said the vaccine was 90% effective in preventing Covid-19 when administered in a half dose followed by a full dose at least a month apart, based on data from end-stage trials in the Kingdom. UK and UK. Brazil. Another dosing regimen was 62% effective when given in two full doses at least one month apart.

Among the volunteers, 131 were infected with the disease, but no hospitalizations or severe cases of the disease were reported in the participants who received the vaccine. The analysis included data from phases 2 and 3 of the survey in the UK and phase 3 in Brazil.

The Oxford vaccine is one of four that are undergoing phase 3 testing in Brazil, in association with the Oswaldo Cruz Foundation (Fiocruz). In August, the federal government said it would invest R $ 1.9 billion to produce 100 million doses. In early November, Fiocruz announced a schedule for the production and distribution of the immunizer in Brazil.

In the last week, two vaccines against Covid-19, Pfizer and Moderna, reported positive results and more than 90% efficacy in phase 3 studies, the last phase before the application for registration with regulators.

Unlike the Pfizer and Moderna vaccine, the Oxford vaccine can be stored, transported and handled under normal refrigeration conditions, that is, between 2 and 8 degrees Celsius for at least six months and administered in existing healthcare settings.

Currently, the Oxford vaccine is in the third and final phase of testing in England, India, Brazil, South Africa and the United States. In September, AstraZeneca stopped global vaccine trials to investigate a participant who developed a form of inflammation called transverse myelitis. In October, a Brazilian volunteer who participated in the vaccine trials died of Covid-19. The participant, however, did not receive the vaccine that was being tested, but a placebo (an inactive substance). The trial is currently ongoing.

In Brazil, three other vaccines are also being tested in phase 3 of clinical trials: Pfizer / BioNTech, Sinovac (CoronaVac) and Johnson & Johnson.

How the 3 phases work

When testing a vaccine, usually divided into phases 1, 2 and 3, scientists try to identify serious adverse effects and whether the immunization was able to induce an immune response, that is, a response from the body’s defense system.

• STEPS: Why Phase 3 Clinical Trials Are Essential to Vaccine Safety and Success

Phase 1 trials generally involve dozens of volunteers; those of phase 2, hundreds; and phase 3, thousands. These phases are generally carried out separately, but due to the urgency of finding an immunization for Covid-19, several companies have taken more than one step at the same time.

Before human testing, vaccines are tested on animals, usually mice and then monkeys.

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