[Kim Jaeho's Life Story]<196> The Charm and Shadow of Antibodies

The novel coronavirus infection (COVID-19) has brought tremendous changes to our society. Last March, a columnist from The New York Times, considering the massive changes expected due to the emergence of COVID-19, divided time into BC (Before Corona) and AC (After Corona) eras, and these changes are still ongoing. Even the remarkable advances in science have not easily subdued the power of COVID-19.

Across the world, numerous researchers and enormous research funds are being competitively invested to develop vaccines (immunizations) and treatments for COVID-19, and the media are racing to report on the progress of these studies. However, despite abundant rumors, no reliable and verified products have yet emerged. There are even movements, pressured by some impatient politicians, to approve use without verifying the most important safety aspects.

The battle between infectious diseases and humans, which has continued for thousands of years, resembles a fight between spear and shield. In times when knowledge and information about infectious diseases were severely lacking, people had few special means to fight them, but the shield prepared inside the body protected against infectious diseases. Infectious pathogens troubled humans whenever this shield malfunctioned and failed to perform its function.

No matter how frightening a pathogen is, it cannot penetrate the skin; it can only enter the body through the mouth, nose, wounds, contact with bodily fluids, or insect bites. If it manages to enter, the body expels it through nasal mucus, coughing, sneezing, mucus in the respiratory or gastrointestinal tract, vomiting, and diarrhea, while the stomach secretes gastric acid to kill them. Bacteria and viruses that survive through these multiple layers of defense are found and killed by immune cells called white blood cells.

As COVID-19 continues to spread, people's attention is focused on the development of vaccines and treatments, eagerly awaiting their arrival. Vaccines and treatments are representative methods that supplement the activity of immune cells when the shield protecting our body from infectious pathogens fails to function properly. Vaccines are made by utilizing the principle that special immune cells called B cells produce antibodies.

When we are infected by external substances (antigens) such as viruses, bacteria, fungi, or parasites, immune cells destroy them and remember the structure of the antigen for a long time. When the same antigen is encountered again, the immune cells produce substances that can easily destroy it; these substances are antibodies. Antibodies can remove the same antigen much faster and more effectively than when the immune cells first encountered the antigen, and they have no side effects, making them very attractive.

Vaccines are substances created by humans to harness the appeal of antibodies. For a vaccine to be effective, it must produce enough antibodies to effectively destroy the pathogen upon infection and have no side effects. To prevent infection when vaccinated, vaccines use weakened or killed pathogens or toxins produced by pathogens instead of normal pathogens.

Making a vaccine prototype is not particularly difficult, but verifying that enough antibodies are produced and that there are no side effects is not easy. It requires long periods and significant costs because it must be verified through numerous clinical trials starting from animal experiments. There is no guarantee of success. There are still many viruses for which vaccines have not been developed, and it has taken more than 10 years to develop vaccines for some.

Given the many researchers devoted to development, the COVID-19 vaccine is likely to be developed faster than any other vaccine. However, there is no guarantee that a perfect product that will instantly suppress the pandemic and protect humanity will be developed. Whether a vaccine that produces antibodies effectively, remains for a long time, and is safe with almost no side effects will be made remains to be seen.

Vaccines are not万能 (万能 means "all-powerful" or "万能" in Chinese characters; here, it means "all-purpose" or "perfect"). They have some preventive effects, but as seen with other vaccines, the effectiveness of antibodies produced by vaccines is often limited, and concerns about side effects and safety have been frequently reported. For example, antibodies produced by the flu vaccine disappear after six months. According to the U.S. Centers for Disease Control and Prevention (CDC), the preventive effect of the flu vaccine is generally around 40-60%, and in some years, it was as low as 19%.

Antibodies produced by vaccines are one of the shields protecting against infectious diseases, but since they have weaknesses, it is not desirable to rely excessively on vaccines. The preventive effect of vaccines is influenced by various factors such as vaccine type, age, and health status. Therefore, it is very important to maintain a pro-life lifestyle that activates the life switch regularly (see Life Story episode 68) to keep the immune system's natural healing ability high.

Jaeho Kim, Independent Researcher