English Researchers: "Moderna Booster After Completing Pfizer Vaccination...Effectiveness Increases by 1000%"

Medical staff are administering vaccines at the COVID-19 Central Vaccination Center of the National Medical Center.
[Photo by Yonhap News]

[Asia Economy Reporter Seoyoung Kwon] A study has attracted attention by showing that 'heterologous vaccination' (mix-and-match vaccination) significantly enhances immunity in relation to the COVID-19 vaccine booster shots.

On the 2nd (local time), The New York Times (NYT) and others reported that researchers at the University of Southampton in the UK recently measured the booster shot effects according to vaccine types on 2,878 people who had completed their second dose of the COVID-19 vaccine. The trial participants were selected as individuals who had received two doses of either AstraZeneca (AZ) or Pfizer vaccines, with at least 70 days having passed since their second dose.

The participants received booster shots with either the same vaccines they had for their first and second doses or different vaccines. The vaccines used in the trial included seven types: AZ, Pfizer, Moderna, Janssen, Novavax, CureVac, and Valneva. Four weeks after the booster shot, the researchers measured the participants' COVID-19 antibody levels and explained, "The booster shot's effectiveness in preventing COVID-19 infection reaches 90%. This means it is effective regardless of the vaccine type received."

The researchers also explained that the effectiveness varied depending on the vaccine type. For those who had received Pfizer vaccines for their first and second doses, receiving the Valneva vaccine as a booster increased antibody levels by 30% compared to the control group, whereas receiving the Moderna vaccine as a booster increased antibody levels by at least 1000%. Accordingly, the researchers analyzed, "Regardless of the vaccine type used for the first and second doses, mRNA vaccines such as Moderna and Pfizer produced significantly more antibodies when used as booster shots compared to other vaccines."

Research on the effects of heterologous vaccination was also conducted. According to the researchers, when people who had received AZ vaccines for their first and second doses received a Pfizer vaccine booster, their antibody levels increased 25-fold compared to the control group. This is a higher figure compared to an 8-fold increase in antibody levels when people who had received Pfizer vaccines for their first and second doses received a Pfizer booster. However, Dr. Saul Faust, who participated in the study, explained, "While it is true that heterologous vaccination shows high effectiveness, COVID-19 infection can be prevented by receiving most types of vaccines regardless of their kind."