Experts question local vaccine's efficacy against COVID-19 variants

08/02/2021 09:35 PM
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Taipei, Aug. 2 (CNA) A panel of experts questioned a local vaccine's efficacy against COVID-19 variants despite agreeing to grant it emergency use authorization (EUA) last month, according to the minutes of the meeting made public Monday.

At the meeting of the panel of 21 experts on July 18, 18 of the 20 who voted agreed to grant EUA to the vaccine made by Taiwan-based Medigen Vaccine Biologics Corp. without the need for Phase 3 clinical trial efficacy data because the vaccine's production of antibodies in Phase 2 trials met preset standards.

They also felt Medigen's vaccine had proven to be safe during the Phase 2 trials.

Given the emergency facing Taiwan amid the pandemic, they believed the benefits of issuing an EUA to Medigen outweighed the risks, according to the minutes.

During the meeting, however, some experts questioned how effective the vaccine will be in real life, especially against the Delta and Beta variants of COVID-19.

They said lab testing showed that the vaccine's antibodies showed better results for some of the early variants of COVID-19, such as the Gamma and D614G variants, but poorer results against the Delta and Beta strains.

They also suggested that lab in-vitro results may not have a linear relationship with the vaccine's effectiveness in real life and cautioned against drawing any conclusions from the in-vitro results.

Given that Taiwanese vaccine makers have yet to conduct Phase 3 trials that are the standard for determining whether a vaccine offers protection against a particular virus, the experts called on Medigen to continue to study its vaccine's efficacy against new variants and see whether a third dose might be needed.

The experts also urged Medigen to consider conducting Phase 3 clinical trails in Taiwan as well, according to the minutes.

The minutes were released amid requests by opposition parties to make public the EUA review process, arguing that most Taiwanese have been kept in the dark.

The approval in itself was controversial because it was based on two arbitrary standards for local vaccine EUA approval set by Taiwan's Food and Drug Administration not found anywhere else in the world.

They had to have a seroconversion rate of above 50 percent and geometric mean titers (representing the concentration of virus neutralizing antibodies) at least equal to two-thirds the level found in recipients of the AstraZeneca vaccine.

The Medigen vaccine had a seroconversion rate of 95.5 percent and generated GMTs that were 3.4 times higher than those found in a control group of 200 people in Taiwan who received two doses of the AZ vaccine.

When the FDA announced the panel's vote of 18 in favor of the EUA, one against, and one member wanting more documentation, on July 18, it did not make any more details public, saying the meeting was held in closed-door fashion to allow experts to express their views freely.

Amid criticism, the Central Epidemic Command Center (CECC) head Chen Shih-chung (陳時中) later agreed to make public the minutes after masking the names of the experts making the comments.

Meanwhile, asked Monday if Taiwan will consider to allow people in high risk groups to get a third COVID-19 vaccine dose in the future, Chen said the main goal at the moment is to get more people to have a first dose.

Only after a majority of people in Taiwan have received two jabs that the CECC will consider a booster shot, he said.

Chen made the remarks when asked to comment Israel's last week announcement to roll out a third dose of the coronavirus vaccine to people over the age of 60, becoming one of the first countries in the world to make such a move.

As of Sunday, around 7.88 million people in Taiwan have received their first shot of a COVID-19 vaccine, which translates into 33 percent of the population, while 388,487, or 1.65 percent, have been fully vaccinated, according to the CECC.

(By Chen Chieh-ling, Chang Ming-hsuan and Joseph Yeh)

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