TAIPEI (Taiwan News) — Taiwan’s Central Epidemic Command Center (CECC) on Wednesday (Sept. 29) reported three breakthrough infections, including two from AstraZeneca and one from China’s Sinovac, a vaccine that has been found by three recent studies to be less effective than its Western counterparts.
Philip Lo (羅一鈞), deputy head of the CECC’s medical response division, announced that three of the 10 imported cases reported that day were considered breakthrough infections. Lo said that two Taiwanese men in their 40s, case Nos. 16,317 and 16,318, who returned to Taiwan from Kazakhstan on Sept. 26, had received doses of the AstraZeneca vaccine in May and July of this year, and both are asymptomatic.
According to Lo, case No. 16,320 is a Taiwanese woman in her 20s who received two doses of the Sinovac vaccine in June before returning to Taiwan from Cambodia in September. She began to experience a cough and runny nose on Sept. 22, but she tested negative for the virus upon arrival in Taiwan on Sept. 26.
Because her symptoms returned, she was tested for the virus again on Sept. 28 and was diagnosed with COVID-19 on Sept. 29. Three contacts have been listed in her case, including two who have entered isolation, while one is undergoing self-health monitoring.
She is the only symptomatic case of the 10 imported infections reported on Wednesday.
A report released by Chile’s Health Ministry in August found that Sinovac was 58.5% effective in preventing symptomatic COVID, 89.7% effective in preventing ICU admissions, and 86.4% effective in preventing death. In contrast, the Pfizer-BioNTech vaccine was 87.7%, 98.3%, and 100% effective in these respective categories, while AstraZeneca also had higher efficacy rates of 68.7%, 100%, and 100%.
A Brazilian study involving 60.6 million recipients also published in August found that those inoculated with Sinovac had a 54.2% lower risk of infection, 72.6 lower risk of hospitalization, 74.2% lower risk of ICU admission, and a 74% lower risk of death. The numbers for those inoculated with AstraZeneca were again significantly higher at 70%, 86.8%, 88.1%, and 90.2%.
Data released by Malaysia’s Health Ministry on Sept. 9 revealed that Sinovac recipients accounted for the highest percentage of deaths among vaccinated individuals. From June 7 to Sept. 6, Sinovac vaccine recipients accounted for 710 of 922 deaths, or 77%, despite comprising only 51.5% of vaccinated people.
In comparison, recipients of the Pfizer-BioNTech vaccine accounted for 206 deaths, or 22.3%, with 43.6 of the population fully inoculated with the jab. This equates to 10.11 vaccine breakthrough deaths per every 100,000 fully vaccinated recipients of Sinovac, compared to 3.47 for every 100,000 BioNTech recipients.
CECC advisor Chang Shan-chwen (張上淳) said the majority of international studies show most cases of breakthrough infection have mild symptoms or are asymptomatic, which is consistent with the expectation that vaccination can prevent severe illness and hospitalization, even if the infection is the Delta variant of the virus. Chang said that with breakthrough cases, the viral load in people who have been vaccinated is also relatively small and the chance of transmission is relatively lower. TAIWAN NEWS