Fases de desenvolvimento de uma vacina
March 17, 2020 -
Está em curso a corrida para encontrar uma vacina contra o coronavírus,
mas as vacinas passam por diversas fases de desenvolvimento – da
descoberta a ensaios em animais, em humanos, aprovação e fabrico.
The Norway-based Coalition for Epidemic Preparedness Innovations (CEPI), made up of vaccine makers and health agencies -- is leading the bid to fast-track a vaccine.
Researchers in the U.S. at Massachusetts-based Moderna, a CEPI-sponsored start-up, began developing a “nucleic acid vaccine.” The vaccine contains the genetic recipe for human recipients to generate antigens -- in this case SARS-CoV-2 viral fusion proteins -- inside their body. These antigens then trigger the immune system to produce antibodies to block the virus.
Forty-five young, healthy volunteers began participating in a trial of Moderna’s vaccine at the Kaiser Permanente Washington Health Research Institute in Seattle on March 16.
A CEPI-sponsored team in Australia is also using the “spike protein” on the outside of the virus. The viral spike protein binds to a receptor on the human cell surface called ACE2 (Angiotensin-converting enzyme 2).
Before being injected into humans, a candidate vaccine goes through pre-clinical trials in which experiments on animals determine whether treatments are safe and effective.
In the next phase, a lengthy series of clinical trials evaluate the vaccine’s safety and ability to generate an immune system response.
The production of a vaccine for large-scale use could take 12–18 months and might not be possible during the current outbreak, explains Nicola Stonehouse, a professor in molecular virology at the University of Leeds. “What it might do is help control future outbreaks,” she says. “To make a vaccine conventionally -- to test it and get it on the market -- can take a decade.”
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