Anvisa temporarily suspends Coronavac clinical trial | Vaccine

This is one of the candidates for the coronavirus vaccine and is developed by the Chinese laboratory Sinovac Biotech in association with the Butantan Institute (São Paulo). With the study discontinued, no new volunteers can be vaccinated.

Anvisa said, through a statement, that it was notified of a serious adverse effect on October 29. However, the agency did not say the specific cause for this suspension. The following are considered “serious adverse events”:

• death
• potentially fatal adverse event
• persistent disability or disability
• patient hospitalization
• congenital anomaly or congenital defect
• any suspected transmission of an infectious agent through a medical device
• clinically significant event.

CBN radio reported that the hiatus in clinical trials came after the death of a volunteer. The information was not confirmed by the agency.

This is the third experimental vaccine against Covid-19 that has had its clinical trials suspended due to serious adverse events.

• The Oxford candidate was stopped testing after a volunteer showed symptoms of a neurological disease.
• The Johnson & Johnson vaccine also stopped testing after an “unexplained illness” in one of the participants.

The Coronavac tests were in the third and final phase (see below). Volunteers who have already been injected will continue to be monitored by the research team.

Steps to produce a vaccine

It takes time to produce a vaccine. The most rapidly developed vaccine to date was the mumps vaccine, which took about four years to be licensed and distributed to the public.

Before testing in volunteers begins, immunization goes through several phases of preclinical experimentation (in the laboratory and with guinea pigs). Only after its safety and efficacy have been evaluated do human trials begin, the so-called clinical phase, which are three:

• Phase 1: is a preliminary evaluation of the safety of the immunizer, performed with a small number of healthy adult volunteers who are closely monitored. It is at this time that the type of response that the immunizer produces in the body is understood. It is applied to dozens of participants in the experiment.
• Phase 2: In the second phase, the clinical study is expanded and has hundreds of volunteers. The vaccine is given to people with characteristics (such as age and physical health) similar to those for whom the new vaccine is intended. In this phase, the safety of the vaccine, immunogenicity (or protection capacity), dosage and how it should be administered are evaluated.
• Phase 3: Large-scale trial (with thousands of people) that needs to provide a definitive evaluation of its efficacy and safety in larger populations. In addition, designed to predict adverse events and ensure the durability of protection. Only after this phase can a medical history be taken.

According to the National Health Surveillance Agency (Anvisa) to carry out a clinical trial in Brazil, the approval of the National Research Ethics Commission (Conep) is required, a body linked to the Ministry of Health. Volunteers are recruited by research centers.