Pfizer and Moderna: Second Dose Essential... Effectiveness Differs from First Dose

Broad Immune Response After Second Dose of mRNA COVID-19 Vaccine
Stanford Research Team "Second Dose Brings Stronger Effect Than First Dose"

[Image source=Yonhap News]

[Asia Economy Reporter Yu Je-hoon] A study has found that receiving two doses of messenger ribonucleic acid (mRNA) COVID-19 vaccines not only significantly increases neutralizing antibodies but also induces a broad immune response. This underscores the importance of not missing the second dose even after the first vaccination.

According to the summary of the paper by Professor Bali Pulendran's research team from Stanford University School of Medicine's Department of Pathology, Microbiology, and Immunology, published on the American Association for the Advancement of Science website on the 28th, the study was conducted to investigate the effects of the mRNA-based Pfizer vaccine on various components of the immune response. Among currently available vaccines, Pfizer and Moderna vaccines use the mRNA platform.

To this end, the research team recruited 56 volunteers vaccinated with the Pfizer vaccine and collected blood samples at multiple time points before and after the first and second doses. During this process, the team confirmed that while the first dose increased the levels of COVID-19-specific antibodies, it did not reach the levels induced by the second dose.

Professor Pulendran explained, "The second dose has a powerful effect that surpasses the first dose," adding, "Antibody levels increased significantly, T cell responses that were not observed after the first dose appeared, and remarkably enhanced innate immune cells also showed a strong response."

In particular, the team focused on the increase of antiviral monocytes. Before vaccination, this monocyte group accounted for only 0.01% of circulating blood cells, but after the second dose, it increased 100-fold to 1%. Furthermore, these monocytes exhibited reduced inflammatory properties but enhanced antiviral activity, suggesting they could provide broad protection against other viral infections as well, Professor Pulendran noted.

Professor Pulendran stated, "It is remarkable that the frequency of these cells abnormally increased just one day after the second dose," and added, "These cells may have inhibitory effects not only on the COVID-19 virus but also on other viruses."

Meanwhile, this study by Professor Pulendran's research team was published in the journal Nature on the 12th.

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