Researchers from Nagoya University have found an explanation for why some people experience long-lasting protection after vaccination against the coronavirus, while others experience rapid decline. It all comes down to the levels of specific antibodies that protect the mucous membranes of the respiratory tract.
A new study from Nagoya University sheds light on one of the main questions of the pandemic: why vaccinated people can still contract COVID-19. Scientists monitored more than 2,500 volunteers for a year and a half and identified four types of immune response after vaccination.
Particular attention was drawn to the group with the so-called “rapid immune decline.” Despite a strong initial response, their protection faded within a few months, and the risk of infection increased again.
The key factor turned out to be IgA(S) antibodies, which are responsible for protecting the mucous membranes of the nose and throat—the main entry points for the virus. People with low levels of these antibodies were significantly more likely to develop breakthrough infections after vaccination. According to researchers, blood testing for IgA(S) levels could become an important tool for assessing individual resistance to COVID-19 and help determine who needs additional booster doses.
Scientists note that other factors, such as age, genetics, sleep quality, and even stress levels, can also influence the longevity of immunity. Therefore, a personalized approach to vaccination could be the next step in the fight against the coronavirus.
