Bahk Eun-ji has been with The Korea Times since 2012, building a career across multiple desks. She began at the Business Desk, where she conducted in-depth interviews with key figures in Korea's corporate world. Later, she moved to the Politics & City Desk, focusing on education policy and social affairs. She later served as team leader of the digital content team, leading curation efforts on the newspaper’s homepage and reshaping print stories for social media audiences to enhance digital reach. Now back on the Politics Desk, she covers the National Assembly and the Ministry of National Defense, with a renewed focus on political developments.
Korea to run clinical test on mixing COVID-19 vaccine doses
A quarantine official disinfects a vaccination center in Seoul, Wednesday, after reopening earlier in the day following a closure amid the supply shortage of vaccines. Yonhap
By Bahk Eun-ji
By Bahk Eun-ji
The government said Thursday that it will conduct a clinical test on mixing COVID-19 vaccine doses from different companies, following an overseas study that showed the vaccination technique was effective.
Under the supervision of the Korea Disease Control and Prevention Agency (KDCA), the National Institute of Health will conduct the test on the safety and efficacy of using different vaccines in the two-shot regimen. Results from the study are likely to determine whether the government will allow this method of vaccination that has been adopted by some European countries
The decision to run the clinical trial follows a study by Spain's state-run Carlos III Health Institute, which said earlier this week that those who received the AstraZeneca vaccine and then the Pfizer vaccine for their second shot had a higher anti-body response to the coronavirus than those getting only AstraZeneca doses.
“We'll conduct the test on people here who received the first dose of AstraZeneca vaccine, with Pfizer or other vaccines approved here,” a senior health official said in a briefing.
About 400 to 500 people in different age groups and genders will be recruited for the test, the official said.
Although it is a principle to use the same vaccine for the first and second doses, studies on mixing have been conducted in Europe as many countries there are struggling with supply shortages, and safety issues with the AstraZeneca vaccine have continued.
In the Spanish study, mixing the vaccines provided greater protection against COVID-19, with those receiving a second dose of the Pfizer vaccine having a seven-fold increase in the number of neutralizing antibodies than those who received only AstraZeneca.
People receiving a second inoculation with the Pfizer vaccine also showed relatively mild side effects, such as headaches, chills and fever, and nobody required serious treatment.
Officials unload containers carrying Pfizer COVID-19 vaccines from a cargo plane that landed at Incheon International Airport, Wednesday. Yonhap
However, the health authorities here have been cautious about mixing doses as the AstraZeneca vaccine is not allowed for those under 30 due to concerns over safety, especially after some serious adverse effects such as blood clotting were reported.
“In general, the effectiveness and safety of mixing vaccines have not been fully proven yet, but the development period of the COVID-19 vaccines was relatively short, so scientific verification is taking place now,” Sohn Young-rae, a senior health official, said in a briefing Wednesday.
“We are also looking into the study by the Spanish institute very carefully.”
Some epidemiologists expressed similar concerns.
Choi Jae-wook, a professor of preventive medicine at Korea University's College of Medicine, said, “The Spanish study was conducted with a limited number of people, 670 participants, so there are still many uncertainties.”
Ma Sang-hyuk, vice president of the Korea Vaccine Society, also said vaccines must be inoculated in accordance with the approved method through clinical research.
“Inoculating a different vaccine for the second shot is basically against normal protocols,” Ma said.
Meanwhile, the KDCA reported 646 more infections Wednesday, including 619 local cases, raising the total caseload to 134,117. A total of 1,180,516 people, or 2.5 percent of the country's population, have been fully vaccinated, receiving both doses of the two-part vaccines, since the government launched its vaccination program, Feb. 26.