For the first results released last Friday (25), the vaccine produced by the Belgian laboratory Janssen Pharmaceuticals (of the Johnson & Johnson group) is safe and produces an immune response against SARS-CoV-19, the virus responsible for the covid-19 pandemic.
The data, obtained from test phases 1 and 2 of the immunization of volunteers (occurred simultaneously), were published in the research repository medrXiv (that is, they have not yet been reviewed by the medical community).
Divided into three groups of volunteers aged between 18 and 55 years (two groups) and 65 years or more (one group), the 796 volunteers received a single dose of Ad26.COV2 between July 22nd and August 24th. In each group, some participants received a booster dose of the vaccine. The most common side effects, reported the day after immunization, were fatigue, fever and headache. The generation of antibodies was similar for all participants.
“Neutralizing antibody responses in all reported participants were obtained after a single dose of Ad26.COV2.S. […] Our study in non-human primates showed that a single immunization provided complete protection against SARS-CoV-2 replication in the lungs and almost complete protection against viral replication in the nose, “says the report.
The laboratory argues that a single dose would be more advantageous in the production, distribution and application of the vaccine during the pandemic. However, he warns that there are still no reliable estimates of what the immune response needed to guarantee protection against the new coronavirus.
In August, Janssen obtained authorization from the National Health Surveillance Agency (ANvisa) for phase 3 tests in the country, with seven thousand volunteers. The vaccine will also be applied to 60,000 people in countries still with a high incidence of covid-19 (Argentina, Chile, Colombia, Mexico, Peru, South Africa and the USA). In the UK, immunization will be given in two doses.