[Kim Jaeho's Life Story]<214> Efficacy and Side Effects of COVID-19 Vaccines

The COVID-19 virus, first discovered in China at the end of 2019, transformed the world into a COVID society within just a few months despite tremendous efforts to stop it. Even the United States and Europe, considered the most advanced countries, failed to achieve significant results with extreme measures that restricted not only normal activities but also minimal movement. As confirmed cases and deaths surged, people found themselves waiting only for vaccines. However, as the awaited vaccines were developed one after another, the situation has greatly improved.

This year, vaccine competition is fierce, especially in countries severely affected by COVID-19. The United States and Israel rapidly progressed with vaccinations, leading to a swift decline in confirmed cases and deaths. South Korea, which started vaccinations later due to relatively fewer patients, is accelerating its vaccination pace by securing additional vaccines, while concerns about vaccine side effects are also being voiced.

The word vaccine refers to immunization, and to understand vaccines, one must understand our body's immune system. White blood cells that make up the immune system recognize bacteria, viruses, fungi, parasites, and even transplanted organs as 'invaders' if they are foreign to the body. These cells attack and destroy such antigens, a process called primary immunity or innate immunity.

During this primary immune response, immune cells with antibodies (memory B cells) are created that remember the destroyed antigens for a long time. When these immune cells encounter the same antigen again, they eliminate it faster and more effectively than the first time. This is called secondary immunity or adaptive immunity.

Vaccines are substances used to create immune cells with antibodies instead of natural infection by pathogens. They use weakened or dead pathogens or toxins produced by pathogens to induce a primary immune response similar to natural infection. The secondary immune response generated by these antibodies is used to prevent disease. COVID-19 vaccines also include RNA and DNA vaccines made using genetically engineered RNA or DNA.

COVID-19 vaccines have played a significant role in curbing the spread of the virus in many countries, but side effects from vaccination are also well known. Most side effects are mild, such as fever, fatigue, headache, muscle pain, chills, diarrhea, and pain at the injection site. However, although rare, serious symptoms such as seizures, low blood pressure, breathing difficulties, blood clots, and loss of consciousness have occurred, and there have been deaths. Why do these side effects occur?

When the immune system encounters a vaccine, it secretes chemicals called cytokines to destroy it, increasing blood flow to circulate more immune cells and raising body temperature. These substances also cause mild side effects such as fever, chills, fatigue, and muscle pain. These side effects are evidence that the vaccine is functioning and the immune system is working; they are normal reactions, not signs of vaccine malfunction. The problem lies in the discomfort experienced.

Therefore, mild side effects are nothing to worry about, and if they become unbearable, medication can be used to alleviate them. Most side effects are not harmful or unsafe except for the discomfort, and they disappear naturally after a few days, so there is no need for major concern.

The immune cells' responses to vaccines vary greatly among individuals, and vaccine side effects are not directly related to immunity. Strong immune cell responses indicate that the immune system is working, not that there is a problem. Likewise, not feeling an immune response does not mean the immune system is inactive. For example, more than 50% of people receiving the Pfizer and Moderna vaccines reported no side effects, yet 94% developed antibodies.

COVID-19 vaccines have contributed significantly to improving the pandemic situation, but vaccines are not the ultimate means to prevent all infectious diseases. While vaccines are helpful in emergencies like the current situation, it is advisable to maintain our health by living a pro-life lifestyle that activates the life switch (refer to Life Story episode 68) to keep the natural healing ability of the immune system’s primary immune response high.

Jaeho Kim, Independent Researcher

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