South Korean health care professionals, who are being offered the country’s first doses of COVID-19 vaccines, on Thursday gave those further down the priority list a heads up on what to expect when they finally get vaccinated.

Onetime director of the Korea Centers for Disease Control and Prevention Dr. Jung Ki-suck said in a phone call with The Korea Herald Thursday morning that his reaction to the AstraZeneca COVID-19 vaccine has been mild so far, though “more feisty” than the seasonal flu vaccine.

“It’s been nearly 24 hours since I got my shot. I’m feeling just a tad feverish, with mild soreness in the upper arm where the injection was given -- which are normal,” he said. Jung, who is 63, received his first dose at 10:50 a.m. Wednesday.

He added that younger people “may react more strongly” to vaccines due to their robust immune systems.

Seoul National Hospital nurse Choi Won-young, 34, said the COVID-19 vaccine “felt worse than your regular flu shot.”

Speaking to The Korea Herald on Thursday afternoon, she said: “I can’t speak for everyone, but my post-vaccination experience felt like having a bad case of the flu.”

Since getting vaccinated on Monday morning, a fever of up to over 38 degrees Celsius, chills, bone pain all over the body persisted for about 36 hours before subsiding, she said. Three days later, her arm was still sore from the injection.

“Some people, such as myself, might need some time off to recover from the mild, but nevertheless distressful, side effects following vaccination,” she said. “I would say get it before the weekend, or when you can afford to take a day or two off afterwards.”

The Korean Vaccine Society’s Vice President Dr. Ma Sang-hyuk, said the reported adverse reactions after getting AstraZeneca shots among his hospital staff in South Gyeongsang Province appeared to be more prevalent and “worse than (he) had expected,” although mild to moderate overall.

For vaccine recipients experiencing “temporary, but unpleasant” side effects, ensuring a day or two’s time off before returning to work might need to be part of the vaccination guidelines, Ma suggested.

He stressed, however, that the problems reported after vaccination did not necessarily mean they were caused by a vaccine.

Infectious disease professor Dr. Kim Woo-joo of Korea University, who received a Pfizer vaccine about 10 days ago, said he felt “some pain around the injection spot,” which signaled to him that “the vaccine is working.”

Kim, 61, said over the phone Thursday these very mild symptoms went away within 30 hours, and that he didn’t need to take any medications.

Asked to compare it to flu shots, he said, “I don’t really recall feeling anything in particular after flu shots, but that’s probably because I’ve been taking them every year for over 20 years now.”

For the concerned prospective vaccine takers, he said feeling lousy after vaccination was “normal.” He also pointed out that for AstraZeneca vaccines, compared with the first dose, adverse reactions reported after the second dose tended to be milder and reported less frequently, according to a UK government report.

Emergency medicine specialist Dr. Paik Jin-hui, who is in his 40s, was inoculated with a Pfizer vaccine on Monday, and said he was “feeling completely fine.”

“Just a bit of soreness around the injection site was all,” he said. “Luckily, I didn’t have any of the other more frequently reported symptoms like fever.”

Paik, who is the vice manager of Incheon’s regional emergency medical center, worries that once the vaccination program reaches the general public, emergency rooms may begin to fill up with patients mistaking vaccine side effects for something else.

“I’m already seeing an influx of vaccinated patients who are complaining of some of the common side effects,” he said.

“My recommendation for those getting the vaccines is to take fever or pain relievers -- over-the-counter medications such as Tylenol (acetaminophen) -- in case of expected symptoms such as muscle ache and mild-grade fever, rather than going to see the doctor immediately.”

As some vaccine side effects do overlap with COVID-19 symptoms, vaccinated people will need to be tested before they can be admitted at clinics and hospitals as well as emergency rooms, he said.

Out of the over 500,000 people who have been given their first shots of the COVID-19 vaccine in Korea, 6,859 have reported experiencing suspected side effects, according to Korea Disease Control and Prevention Agency statistics.

The vast majority, 6,782 people, had known side effects such as fever, body ache and chills. These mild side effects typically dissipate on their own within a few days, the agency said. More serious problems that have been reported include anaphylaxis-like reactions (57 cases), seizures (five cases) and death (15 cases).

Investigations so far have revealed no links between the adverse events and the vaccines.

Currently, the most widely administered COVID-19 vaccines here are from AstraZeneca. The first batch, which arrived in the last week of February, included 1.5 million doses of AstraZeneca’s COVID-19 vaccine and 58,500 doses of Pfizer’s.

Korea on Thursday backtracked on its early recommendations and approved the AstraZeneca vaccine for people aged 65 and older. This decision, by expanding vaccine eligibility, is expected to accelerate vaccination efforts in the country.

By Kim Arin (arin@heraldcorp.com)