Hongkongers to be guinea pigs for Chinese vaccine

City government OKs CoronaVac though jury still out on efficacy

Hong Kong to begin vaccinating citizens with CoronaVac

Hong Kong to begin vaccinating citizens with CoronaVac (Taiwan News photo)

TAIPEI (Taiwan News) — A report released by Hong Kong's Advisory Panel on COVID-19 Vaccines shows the city's government has greenlit a Chinese vaccine despite the spotty results of local trials.

On Thursday (Feb. 18), Hong Kong's Food and Health Bureau authorized CoronaVac, a vaccine produced by Chinese biopharmaceutical Sinovac, for emergency use. The bureau based its decision on the recommendation of the Advisory Panel, which suggested that the benefits of rolling out CoronaVac outweigh the risks.

Hong Kong aims to inject its first dose of CoronaVac on Feb. 26, joining several other governments, including Indonesia, that have approved the vaccine. Countries such as Malaysia and Singapore have struck a deal with Sinovac but assured their citizens that no doses would be delivered before more evidence shows CoronaVac is safe and effective.

Based on the data submitted by Sinovac, the Advisory Panel in a news conference on Feb. 16 claimed CoronaVac has an efficacy rate of between 50.65 and 91.25 percent in adults aged 18 and older, citing the results of studies in Brazil and Turkey. It added that the vaccine is safe and has been approved by multiple regulatory agencies abroad.

However, in an evaluation that includes data from small-scale local trials, the panel found the vaccine efficacy rate to be only 49.12 percent, with the values ranging from 33.01 to 61.36 percent with a 95-percent confidence interval (CI). The rate for an interval equal to or longer than 21 days was 62.32 percent.

The 95-percent confidence interval indicates that 95 percent of the trial results are likely to fall within the given range.

According to the panel, the results show 21 days to be the recommended dosing interval for optimal vaccine efficacy, but further study with a larger sample size is necessary to confirm this since its lower bound of 95-percent CI did not meet the 30-percent minimum requirement for a vaccine to be listed under "emergency use."

In the eyes of some medical professionals, the vaccine evaluation was rushed through to justify the administration of CoronaVac.

"The samples in the trial are far from enough. They found 8,000 to take part in the trial and came up with a rate lower than 50 percent, so they found another 1,500 for a 28-day trial to get 62 percent to convince the public," a senior medical student going by the nom de plume "No Stake" wrote in an article published by Standnews.

He criticized the trial as unconvincing, citing another result from a subgroup analysis in the report that showed the efficacy rate in the 60+ age group to be 51.11 percent with a 95-percent CI from -166.93 to 91.04 percent. This figure suggests the sample size was too small for the test to be statistically meaningful.

The medical student warned the stakes of recklessly approving a risky vaccine are not just about wasted money but also the harm brought by potential side effects. Premature deployment could also create a "false sense of security" that costs the whole of society the opportunity to receive a more effective vaccine, he wrote.

The Hong Kong authorities are preparing a sum of HK$1 billion (US$128.98 million) to compensate those who experience severe side effects after vaccination, including loss of smell or taste or facial paralysis. Those aged 40 and under could receive up to HK$3 million if the jab significantly damages their health.

Updated : 2021-03-05 12:45 GMT+08:00