Understanding COVID-19 Vaccine Response Patterns and Their Impact on Infection Risk

A recent study highlights that the immune response to COVID-19 vaccines varies significantly among individuals, falling into four distinct patterns. Researchers from Nagoya University tracked antibody levels in 2,526 people over 18 months to classify these responses using advanced mathematical models and AI analysis. They identified groups including those with durable immunity, rapid-decliners, vulnerable responders, and intermediate responders.

One of the key findings is that individuals in the rapid-decliner group, despite showing strong initial antibody responses, experience a quicker drop in protective antibodies, especially IgA(S), which is crucial for mucosal immunity in the nose and throat. These individuals were found to be at higher risk of breakthrough infections, occurring earlier than in other groups.

The study also observed that lower blood levels of IgA(S) antibodies correlate strongly with reduced nasal IgA(S), suggesting blood tests could assist in identifying those at greater risk for breakthrough COVID-19 infections. Interestingly, classical one-time blood tests for IgG antibodies may not accurately predict infection risk, highlighting the importance of tracking antibody levels over time.

Results showed that roughly 29% of participants maintained high, durable antibody levels, while about 28% were vulnerable responders, and 19% were rapid-decliners. The incidence of breakthrough infections was slightly higher among the vulnerable and rapid-decliner groups, at around 6%, compared to 5.2% in durable responders.

Professor Shingo Iwami emphasizes that early antibody decline and biological factors like age, genetics, environmental influences, and medication use play roles in immune response variability. The research suggests that personalized antibody monitoring could inform booster shot timing and improve vaccination strategies. However, further studies are necessary to assess the practicality and cost-effectiveness of widespread antibody testing.

This research provides valuable insights into immune response patterns post-vaccination and offers potential pathways toward more tailored COVID-19 prevention efforts.

Source: https://medicalxpress.com/news/2025-09-covid-vaccine-responses-patterns-rapid.html