South Korea is investigating a series of deaths following flu vaccinations for possible association with vaccines affected by heat fluctuations or syringes found to induce contamination.

The Korea Disease Control and Prevention Agency said Wednesday that at least nine suspected flu vaccine-related deaths have been reported so far. The agency said it would perform autopsies on eight of the cases jointly with respective municipal offices.

“The agency has yet to confirm whether the deaths are an outcome of the vaccination. The epidemiological surveys and post-mortem examinations are still underway,” said the director Jung Eun-kyeong in a briefing.

In the past month, more than 1 million doses of flu vaccines have been withdrawn due either to mishandling or contamination, or both. But the remaining 8 million doses have been authorized for use again after the Ministry of Food and Drug Safety concluded they were still safe and effective.

There have been 431 reported adverse events following flu vaccinations as of Wednesday, which is much higher than 2019’s 177 and 2018’s 132.

Jung attributed the higher-than-average number of side effects being discovered this year to the agency’s active monitoring. “We are checking up on people who were administered with vaccines with issues for any suspicious reactions,” she said.

According to the latest available data, 3,045 people are believed to have been inoculated with vaccines that underwent varying ranges of heat exposure. A further 17,812 people have been given vaccines packaged in syringes deemed to cause unusual particles.

Jung said based on information gathered so far, the events are not understood to be caused by the vaccines, and that the vaccinations would carry on.

Among the known cases of death is a 17-year-old boy who died at his home in Incheon two days after he had gotten a flu shot last week. He reportedly had no preexisting conditions.

The latest reported casualties involved a 53-year-old Seoul woman and a 89-year-old man in Gyeonggi Province, who died Tuesday and Wednesday, respectively.

Separately, a Daegu man in his 70s was admitted to the emergency room about an hour and a half after getting a flu shot at a clinic near his home Tuesday and died Wednesday.

Other cases include a 68-year-old man who died at around 1:10 a.m. Wednesday. He was given a flu shot Tuesday morning. Another man, 82, in Daejeon died at around 3 p.m. Tuesday approximately four hours after he received a flu shot earlier that morning. In Gochang, South Jeolla Province, a woman, 77, died at 7 a.m. Tuesday, a day after she received the flu shot Monday morning.

Details regarding two other people who died were not disclosed upon request from their families.

Former director of Korea’s Centers for Disease Control and Prevention and pulmonologist Dr. Jung Ki-suck said the authorities need to communicate the findings from the investigations as promptly as possible in order for the influenza vaccination program to continue as planned.

Flu vaccinations were already suspended last month over handling errors. A further delay or hesitancy from the public due to a lack of transparent communication could result in a backlog of people failing to be vaccinated at the crucial time before the disease’s peak in November, he warned.

“Too many deaths have occurred in a short span of a couple of days. Before the agencies in charge are able to identify the causes, no one is going to be able to comment on (the vaccine’s) safety,” he said.

The public health agency declined to respond to questions from reporters on the deceased flu vaccine recipients during a briefing held in the immediate aftermath of the news Tuesday. Press inquiries went largely unaddressed until the first briefing on the flu vaccines late Wednesday afternoon.

Infectious disease specialist Dr. Kim Woo-joo of Korea University Medical Center in Guro, southern Seoul, pointed out the vaccines that experienced a cold chain breach or were found to contain contaminants should have been discarded per guidelines.

“Every decision being made has to be based on principles of science, in a way that can minimize risks,” he said.

Pulmonologist Dr. Han Chang-hoon of the National Health Insurance Service Hospital in Ilsan, Gyeonggi Province, said an autopsy was not likely to establish the link between the vaccine and death from a possible adverse event.

“Flu vaccines may cause allergic reactions -- albeit very rarely -- such as anaphylaxis which can be life-threatening. These reactions typically begin soon after the vaccination,” he said. For people with a history of egg allergy who have had severe symptoms such as breathing difficulties, vaccine administration must proceed under strict supervision.

Another pulmonologist, Dr. Chun Eun-mi of western Seoul’s Ewha Womans University Medical Center said there were other preventive measures that can be taken by people who fail to receive flu vaccines due to shortages or other reasons.

“Physical distancing, hand hygiene and face masks go a long way in preventing respiratory diseases,” she said. Flu cases were almost nonexistent during the colder months this year between winter and spring as social distancing and face mask-wearing became more common.

But for some demographics, forgoing flu vaccinations can be riskier. Babies and children under 7 years of age, pregnant women, the elderly and people with medical conditions or otherwise at risk of severe illness are highly urged to get vaccinated, according to the influenza immunization guidelines.

Another key piece of advice is to follow precautions before and after receiving a flu vaccine, according to Kim of the Korea University Medical Center.

“Dress warmly on your trip to the doctor’s office. Older adults are advised to be accompanied. Drink lots of fluids and take plenty of rest after getting a shot. Pay extra attention to how you are feeling for a few days following vaccination,” he said.

By Kim Arin (arin@heraldcorp.com)