Experts Say "Benefits of Vaccination Outweigh Risks of Adverse Reactions Like Myocarditis and Pericarditis"... "Current Outbreak Is 'Among the Unvaccinated'"

Professor Kim Gye-hoon of the Department of Cardiology at Chonnam National University Hospital is answering a video question during a special COVID-19 briefing where experts respond to inquiries about COVID-19 vaccination for people aged 18 to 49, held on the afternoon of the 26th at the Korea Disease Control and Prevention Agency in Cheongju, Chungbuk. From left to right: Professor Jeong Jae-hoon of Preventive Medicine at Gachon University College of Medicine, Professor Kim Gye-hoon of the Department of Cardiology at Chonnam National University Hospital, Director Jeong Eun-kyeong, and Professor Choi Won-seok of Ansan Hospital, Korea University.
[Photo by Yonhap News]

[Asia Economy Reporter Lee Chun-hee] The COVID-19 vaccination for the last group in the domestic vaccination plan, those aged 18 to 49, began on the 26th. They will receive messenger ribonucleic acid (mRNA) vaccines at nationwide designated medical institutions and vaccination centers. Among the two types of mRNA vaccines, this week's recipients will be administered the Pfizer vaccine. Subsequent vaccinations will be determined weekly based on supply conditions.

The Korea Disease Control and Prevention Agency (KDCA) COVID-19 Vaccination Promotion Team, marking the start of full-scale vaccination for the young adult group aged 18 to 49, provided guidelines on behavior before and after vaccination, symptoms and adverse reactions that may occur post-vaccination, and how to respond, as well as a session to address public questions about the vaccine.

On this day, questions sent directly by the actual vaccination targets?college students and office workers aged 18 to 49?were answered by experts including KDCA Director Jeong Eun-kyung, Professor Jeong Jae-hoon of Gachon University College of Medicine’s Department of Preventive Medicine, Professor Kim Gye-hoon of Chonnam National University Hospital’s Department of Cardiology, and Professor Choi Won-seok of Korea University Ansan Hospital’s Department of Infectious Diseases.

Professor Kim Gye-hoon addressed concerns about myocarditis and pericarditis, representative adverse reactions of mRNA vaccines, stating, "When weighing the pros and cons, there is no doubt that vaccination is necessary," and explained, "In fact, the likelihood of myocarditis is higher when infected with COVID-19 than from vaccination."

Professor Choi Won-seok commented on the ongoing increase in severe cases and deaths despite significant calming of vaccinations during the '4th wave,' saying, "It is important to evaluate vaccine effectiveness by looking at the ratios of patients, severe cases, and deaths occurring in vaccinated versus unvaccinated groups, as well as the vaccination rate among confirmed cases," and added, "Some have even called the current outbreak a 'wave among the unvaccinated' due to the large number of patients, severe cases, and deaths in the unvaccinated group," emphasizing the importance of vaccination.

On the morning of the 26th, when full-scale vaccination for young and middle-aged adults (18-49 years old) began, a citizen is receiving the Pfizer vaccine at Sarangui Hospital in Gwanak-gu, Seoul. 2021. 8. 26 Photo by Joint Press Corps

The following is a Q&A with them.

- There are concerns that mRNA vaccines may cause myocarditis or pericarditis. Should young people, even those with mild symptoms, still get vaccinated?

▲(Professor Kim Gye-hoon) Analyzing vaccine recipients in our country, the COVID-19 vaccine shows an infection prevention effectiveness of 82.6%, severe disease prevention effectiveness of 85.4%, and death prevention effectiveness of 97.3%. On the other hand, vaccine side effects occur in 0.42% of cases, with about 0.53% among those aged 18 to 49. Approximately 98% of these were mild symptoms such as headache and muscle pain. Therefore, when weighing the pros and cons, there is no doubt that vaccination is necessary.

Looking at overseas cases, in the United States, among 114 million people who completed two doses of mRNA vaccines, about 497 cases of myocarditis occurred. This is a very rare incidence rate of 3.5 per million. Conversely, if 1 million people under 30 receive the vaccine, about 9,600 would gain protection against the COVID-19 virus, 300 would avoid hospitalization, 60 would avoid progression to severe disease, and 3 would avoid death. Again, weighing the pros and cons, vaccination is the answer.

Moreover, myocarditis occurs quite frequently when infected with the COVID-19 virus. A study on 1,597 young athletes in the U.S. found that 2.3% developed myocarditis, with 0.7% showing symptomatic myocarditis. In reality, the chance of myocarditis is higher when infected with COVID-19 than from vaccination.

- If someone has previously suffered from myocarditis or pericarditis, can they still receive the mRNA vaccine?

▲ (Professor Kim Gye-hoon) Myocarditis and pericarditis are diseases that can be completely cured. Most patients’ heart function returns to normal within six months, and pericarditis is mostly cured within 1 to 2 weeks. Except for cases where myocarditis or pericarditis occurred very recently, if fully recovered, vaccination is allowed.

- If someone experienced suspected myocarditis or pericarditis symptoms after the first dose, should they still receive the second dose as scheduled?

▲ (Professor Kim Gye-hoon) If myocarditis or pericarditis symptoms appeared after the first dose, it is recommended to postpone vaccination. The causes of myocarditis and pericarditis are presumed to be various but are not yet certain, so there is a possibility of recurrence. There is also discussion about receiving a different vaccine than mRNA, but data on this is very limited. For now, it is best to be cautious, follow preventive measures, and wait for further research results.

Jung Eun-kyung, Commissioner of the Korea Disease Control and Prevention Agency, is speaking at a special COVID-19 briefing where experts answer questions about COVID-19 vaccination for people aged 18 to 49, held on the afternoon of the 26th at the Korea Disease Control and Prevention Agency in Cheongju, Chungbuk.
[Image source=Yonhap News]

- For college students, the vaccination period overlaps with midterm exams. Since vaccination may cause unavoidable absences, is there a possibility of introducing vaccine leave or vaccine excused absence?

▲ (Director Jeong Eun-kyung) On the 10th, the Ministry of Education recommended that universities introduce and operate vaccine excused absence for enrolled students receiving vaccination during the semester. However, whether and how to implement this is autonomously decided by each university based on their academic operation plans and circumstances, so it is necessary to check each university’s policy.

- Is vaccination necessary even for those who have recovered from COVID-19 infection?

▲ (Professor Choi Won-seok) Vaccination is recommended even for those who have had COVID-19. First, natural infection also induces immunity like vaccines, but the risk of reinfection increases over time. Studies show that reinfection risk is low for about 5 to 6 months but increases afterward. Considering recent variants require higher levels of neutralizing antibodies, this period may have been shortened.

Second, immune responses induced by vaccines tend to be stronger than those induced by natural infection. Clinical studies comparing immune responses after vaccination and in recovered patients show that antibody levels after vaccination are often several times higher.

Additionally, studies show that previously infected individuals gain additional benefits from vaccination. A recent U.S. study comparing reinfection risk by vaccination status found that those without vaccination had about twice the risk of reinfection.

Therefore, vaccination is recommended even after COVID-19 infection. However, vaccination should be done after isolation is lifted and the individual has recovered. Also, if antibody treatments or plasma therapies were used during treatment, a 90-day interval is recommended.

- What is the reason for allowing AstraZeneca (AZ) leftover vaccine administration to those aged 30 and above recently? How do the benefits and risks of AZ vaccination compare for people in their 30s and 40s?

▲ (Professor Jeong Jae-hoon) Experts recommend vaccination not because it is 100% safe or 100% effective, but because the potential benefits outweigh the risks.

The potential harm from COVID-19 includes the incidence and fatality rate of rare thrombosis, which have stable values through continuous updates. Meanwhile, the benefits of vaccination vary greatly depending on the epidemic situation. Vaccine supply relationships with other vaccines must also be considered.

From this perspective, the initial 30-year age limit and later 50-year limit were evaluated when daily confirmed cases averaged 600 or 1,200, with a worst-case of about 1,800. Currently, with the Delta variant spreading, confirmed cases have exceeded 1,600 even in the best scenario.

The benefits now are about two to three times greater than past evaluations. Even with very conservative assessments for those under 50, the benefits for those aged 30 and above are significant. Therefore, even if the overall age limit is not lowered to 30, the option to vaccinate is open for those who wish to do so due to personal reasons or unavoidable circumstances.

On the 21st, medical staff are administering COVID-19 vaccines at the vaccination center set up in the Health Healing Culture Center in Yangcheon-gu, Seoul. [Image source=Yonhap News]

- Although the 4th wave has intensified, evaluations say the fatality rate has decreased due to vaccine effectiveness, yet deaths continue. What evidence do we have that vaccine effects are showing?

▲(Professor Choi Won-seok) It is important to evaluate vaccine effectiveness not only by the ratio of severe cases and deaths relative to the outbreak size but also by the ratios of patients, severe cases, and deaths occurring in vaccinated versus unvaccinated groups, and the vaccination rate among confirmed cases. It is important to look at proportions within the total scale, not just the absolute number of breakthrough infections. These ratios correspond to the previously mentioned severe disease prevention effectiveness of 86.4% and death prevention effectiveness of 97.3%.

Analyses from other countries also show that large numbers of patients, severe cases, and deaths occur mostly in the unvaccinated group. Some even call the current outbreak a 'wave among the unvaccinated.' Vaccine effectiveness is not 100%, so there is still a risk of severe disease or death among vaccinated individuals. However, vaccines significantly reduce these risks, as confirmed by data from Korea and other countries.

- The second dose is administered six weeks after the first dose. Does the vaccine still work effectively with this interval?

▲(Professor Choi Won-seok) mRNA vaccines are designed to be administered at intervals of 3 or 4 weeks, and following this schedule is most desirable because clinical trials were based on it.

However, a longer interval does not necessarily reduce effectiveness. Multiple-dose vaccines require some immune response after the first dose to enhance and prolong immunity with subsequent doses. If the second dose is given too soon, before sufficient immune response develops, it may be ineffective, and re-vaccination is generally recommended.

There is limited but some research comparing immune responses between groups with 6 to 14 weeks intervals and those with 3 to 4 weeks intervals for the Pfizer vaccine, showing similar or even higher immune responses in the longer interval group, though these findings have not yet undergone peer review.

However, for variants, completing vaccination is important, so the delay in completion is a concern. Even for those who have received only one dose, it is advisable to remain cautious until the second dose is completed and sufficient time has passed.

- Countries like Israel and the United States are preparing booster shots. When will Korea start booster vaccinations? Is there a concern about vaccine shortages if additional doses are given to all citizens?

▲(Professor Choi Won-seok) Before variants, it was estimated that antibody levels would not quickly drop below protective levels and would last a considerable time. However, variants reduce neutralizing ability, so the need to boost immunity arises sooner. Plans are underway or in progress to administer boosters to those vaccinated earliest or to severely immunocompromised individuals whose immune response may decline significantly.

In Korea, basic vaccination is expected to be completed around September to October, and booster vaccinations may begin afterward. Priority groups for boosters may include elderly residents in long-term care facilities, chronic disease patients, frontline healthcare workers, and severely immunocompromised individuals.

▲(Director Jeong Eun-kyung) The government is also developing booster shot plans with experts. Booster vaccinations are expected to start as early as the fourth quarter, and details will be announced once plans are finalized.

Regarding vaccine shortages, about 190 million doses have been secured this year for basic vaccinations. This supply is sufficient for two doses for the entire population, vaccinations for children, adolescents, clinical trial participants, and booster shots within the year. Some fourth-quarter supply will be carried over to next year for additional vaccinations in the first quarter. Additionally, a budget is being prepared to secure 90 million new doses for next year’s additional vaccinations and variant responses, with 30 million Pfizer doses already contracted for next year.

On the 9th, when the second dose of the COVID-19 vaccine for high school seniors began, a student received the Pfizer vaccine at the Dongjak-gu 2nd Vaccination Center set up at the Dongjak-gu Community Sports Center in Seoul.
[Photo by Yonhap News]

- There are internet rumors that deaths from vaccination exceed deaths from COVID-19 infection. Is this true?

▲(Professor Jeong Jae-hoon) It is absolutely not true that the number of deaths reported after vaccination exceeds deaths from COVID-19 infection. As of today, 492 deaths have been reported as adverse events after vaccination, while cumulative deaths from COVID-19 total 2,222.

However, a reported death after vaccination does not mean causality with vaccination is proven. If the entire population were vaccinated simultaneously, it would be unlikely that no deaths or health issues would be reported within 1 to 2 weeks. It is necessary to thoroughly separate naturally occurring deaths and illnesses from those caused by vaccination. This separation is done through causality assessment of vaccine adverse events.

In Korea, two deaths have been confirmed as causally related to vaccination, with several more under review. Even considering these two deaths, the potential harm from vaccination is overwhelmingly outweighed by the benefits.

- Clinical trial results from a U.S. pharmaceutical company show that booster shots increase antibody levels more than ninefold for Janssen vaccine recipients. Is there a booster shot plan for Janssen vaccine recipients?

▲(Director Jeong Eun-kyung) Currently, booster shot plans prioritize high-risk groups and healthcare workers. Detailed implementation plans are being prepared. Additional vaccination plans according to vaccine type will be announced later.

This content was produced with the assistance of AI translation services.