Got Pfizer... "Pfizer Antibodies Decline Faster Than Moderna," Study Finds

Lower Antibody Production Rates with Increasing Age

Medical staff are preparing the vaccine.
Photo by Yonhap News

[Asia Economy Reporter Na Ye-eun] Overseas research results have shown that the antibody levels from the Pfizer COVID-19 vaccine decrease faster than those from the Moderna vaccine.

According to the recent publication in the international journal Frontiers in Immunology, a research team from the University of Virginia in the United States tracked the COVID-19 antibodies remaining in the body after vaccination and reported these findings.

The study was conducted on 234 individuals who completed the primary vaccination series with Pfizer, Moderna, or Janssen vaccines between December 21, 2020, and May 1, 2021. Among the participants, 114 received Pfizer, 114 received Moderna, and 6 received Janssen vaccines.

The results showed that between 7 to 20 days after the second dose, Pfizer and Moderna vaccine recipients had antibody levels approximately 50 times higher than those who received the Janssen vaccine. Subsequently, antibody levels began to decline in both mRNA (messenger RNA) vaccine recipients, but the decrease was more pronounced in the Pfizer group.

When the research team reanalyzed the data six months later, the COVID-19 antibody levels in Pfizer vaccine recipients were lower than those in severely ill COVID-19 patients who had been hospitalized or in Moderna vaccine recipients.

Among Pfizer vaccine recipients, older age was associated with lower antibody production rates, whereas age did not significantly affect antibody production in Moderna recipients. Both Pfizer and Moderna vaccines produced similar peak antibody levels after vaccination.

The research team analyzed that the difference in dosage between the two vaccines influenced the rate of antibody decline. The effective substance administered per dose of the adult Pfizer vaccine is 30 micrograms (μg; one-millionth of a gram), while the Moderna vaccine contains 100 μg per dose.

The research team explained, "All three vaccines used in this study demonstrated sufficient efficacy in protecting patients from severe illness, hospitalization, and death after COVID-19 infection," adding, "These findings may help explain differences in COVID-19 infection rates among people vaccinated with different vaccines."

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