People are observed for possible side effects after receiving their COVID-19 vaccine injections at a vaccination center in Seodaemun District, Seoul, Thursday. Yonhap
By Lee Hyo-jin
Concerns are rising over mix-and-match inoculation of COVID-19 vaccines, following the death of a police officer who received a Pfizer dose for his second shot after an AstraZeneca for his first one.
This is the first death reported since July 5 when the Korean government introduced mix-and-match inoculations, using the AstraZeneca vaccine for the first dose and Pfizer for the second.
A 52-year-old police officer at Chilgok police station in North Gyeongsang Province died, July 20, three days after having been administered with a Pfizer dose. After his family found him unconscious at home around 2 a.m., he was transferred to a nearby hospital, but was pronounced dead about an hour later.
He received his first shot of the AstraZeneca dose April 28, followed by a Pfizer vaccine on July 17. He exhibited symptoms of headache and chills after the second dose, according to his family.
The Korea Disease Control and Prevention Agency (KDCA) said it will take the incident seriously and launch a thorough investigation looking for any correlation between his death and the vaccination.
“We will announce the final results after reviewing the results of the ongoing epidemiological investigation and autopsy findings,” Bae Kyung-taek, a senior KDCA official, said at a briefing, Thursday.
Around 820,000 people here have received mixed vaccines, among some 6.7 million fully vaccinated individuals as of Thursday, according to the KDCA.
“As this is the first death reported after a cross-vaccination, it is very important for health authorities to relieve public anxiety by announcing accurate investigation results,” said Chon Eun-mi, a professor of respiratory medicine at Ewha Womans University Mokdong Hospital.
“The government should also consider giving people more choice on mix-and-match vaccinations.”
Vials with Pfizer-BioNTech and AstraZeneca coronavirus vaccine labels are seen in this March 19 photo. Reuters-Yonhap
Kim Woo-joo, a professor of infectious medicine at Korea University also said, “It would have been better if eligible recipients for mix-and match vaccines were given a choice like in Germany.”
Although emerging studies from overseas indicate that interchanging the vaccines may lead to stronger immune response, some countries are against the protocol citing a lack of data on safety and efficacy.
Data has been released from trials in Spain and the United Kingdom, which suggest that mixing AstraZeneca and Pfizer vaccines triggers an immune response similar, or even stronger than two doses of the same vaccine. A recent study in Germany revealed similar results that the immune response of mixing coronavirus doses was better than two AstraZeneca shots.
Based on such findings, several governments are interchanging the vaccines amid ongoing global shortage in vaccine supply.
Canada has decided to offer mRNA vaccines ― Moderna or Pfizer ― as a second shot to people who have received a first dose of the adenovirus AstraZeneca vaccine. The Thai government also adopted the policy by mixing Sinovac vaccine for a first shot with AstraZeneca for a second one.
Meanwhile, the U.S. has decided against mixing the vaccines, with the CDC firmly stating that “COVID-19 vaccines are not interchangeable,” and thus “Both doses of the series should be completed with the same product.”