VOI - Voice of Indonesia | RRI - Radio Republik Indonesia

All vaccines, including those against COVID-19, are tested for safety and efficacy at all stages of clinical trials, from Phase 1 to Phase 3, head of the Eijkman Institute for Molecular Biology, Amin Soebandrio, said.

"Phase 1 is for testing safety; (at this stage of a trial) for the first time it (a vaccine) is injected into humans, so the numbers (of volunteers) are small first, several tens of people," Amin said in Jakarta on Monday.

Vaccine testing involves comparing a sample of people who get a vaccine against those who do not, he said adding, COVID-19 vaccines are tested for their ability to boost immunity against the virus.

During clinical trials for vaccines, one group of people receives an injection that contains the vaccine, while another group receives an injection that does not contain the vaccine, also known as a placebo, he explained further.

"Then, compared to what percentage the symptoms develop, for example if the difference is very large or those that cause symptoms do not exist at all, then it will be declared safe," he added.

If the group administered a vaccine and the group given a placebo do not show any adverse effects, a vaccine is declared safe, he stated.

"The point is that if it is safe if we can show the risk is much smaller than the expected benefits," Amin said.

Phase 2 clinical trials involve several hundred people, he said. At this stage, the results are reviewed to determine the efficacy and side-effects of a vaccine, he added.

If a vaccine passes stages 1 and 2 of clinical trials, then it enters stage 3 trials, during which it is administered to thousands of people to check whether it is safe, effective, and useful, Amin said.

Volunteers who receive a COVID-19 vaccine in Phase 3 trials may likely have been exposed to the SARS-CoV-2 virus, which causes COVID-19, during their daily activities, he added.

Clinical trials also help determine the vaccine dosage that best provides protection and is still safe to administer without any negative effect on recipients, he continued.

Therefore, all vaccines must complete Phase 1, 2, and 3 clinical trials, with results targeted to strengthen a person's immune system, he stressed. (antaranews)