Two Koreans have died after being injected with AstraZeneca's vaccine.

Jeong Eun-kyeong, the chief of the Korea Disease Control and Prevention Agency, in an emergency briefing on Wednesday said, "Fatalities have been reported following coronavirus vaccine injections and we are investigating the relationship between the injections and their deaths."

According to the KDCA, the first person to die was a man in his 50s who received the injection at a hospital in Goyang, Gyeonggi Province on Tuesday morning. He complained of chest pain, nausea and breathing difficulties 11 hours after receiving the vaccine and died on Wednesday morning.

The second victim was a man in his 60s who received the vaccine in a hospital in Pyeongtaek, Gyeonggi Province last Saturday. He developed a fever, muscle aches and other symptoms 33 hours after being vaccinated and also died on Wednesday morning.

Both had been hospitalized, one due to a heart problem and the other with a cerebrovascular disease.

A woman is being vaccinated in a hospital in Gwangju on Wednesday.

Health authorities are bracing for an increase in fatalities. On Wednesday alone, 64,644 people received their jabs, raising the cumulative number of inoculations to 87,428 people -- 1,154 with Pfizer's vaccine and the rest with the AstraZeneca vaccine. But all side effects so far have been found with those who were given AstraZeneca.

In addition to the two fatalities, three others showed symptoms of anaphylactic shock or severe allergic reactions, but two of them recovered. There have been 204 reports of people with mild symptoms such as headaches, fever and nausea.

Jeong urged the public not to panic and get their jabs despite the reports of side effects. "More than 200 million people around the world already received their vaccinations, but no major side effects have been reported other than anaphylaxis," she said. "These vaccines are deemed safe."

Jung Jae-hun at Gachon University's Gil Medical Center said, "Most patients in nursing homes or hospitals who are being vaccinated right now are not healthy, and it looks like there are fatalities unrelated to the inoculations. There is no need to be excessively nervous, as long as there has not been a sharp increase in deaths."

Meanwhile, the number of coronavirus infections increased 424 as of Thursday morning to a cumulative total of 91,240.