Is a New Omicron Vaccine Needed... "Pfizer and Moderna Show Reduced Preventive Effect"

Immune Response Drops Sharply After Second Dose

COVID-19 Vaccine. /Photo by Yonhap News

[Asia Economy Reporter Na Ye-eun] Research results have shown that messenger RNA (mRNA) vaccines such as Pfizer and Moderna have very low preventive effects against the Omicron variant. Accordingly, the research team argues that the development of new vaccines is necessary.

On the 2nd (local time), according to CNN in the United States, a research team from the Icahn School of Medicine at Mount Sinai in New York City examined the blood of individuals who had received two doses of the Pfizer or Moderna vaccines or a booster shot (third dose).

The experiment showed that immunity formation against Omicron significantly decreased even after completing two doses of both vaccines.

Neutralizing antibodies against Omicron decreased more than 14.5 times in all 85 blood samples compared to the Beta variant and the original strain.

In particular, 16.5% of the samples had almost no neutralizing ability against Omicron. This included three-quarters of the blood samples from individuals who had recovered from infection. Antibodies isolated from COVID-19 recovered patients are estimated to have weaker neutralizing ability against Omicron than vaccine-induced antibodies.

By vaccine type, blood from people who received two doses of the Pfizer-BioNTech vaccine produced neutralizing antibody levels 23 times lower against Omicron, while antibody levels in those vaccinated with Moderna were 42 times lower. Neutralizing activity in those who received additional doses was 7.5 times lower for Pfizer-BioNTech and 16.7 times lower for Moderna.

The result that protection against reinfection significantly decreases after existing vaccination generally aligns with previous vaccine efficacy test results against the Omicron variant conducted in the UK and South Africa.

Meanwhile, the effect of the booster shot was partially confirmed. The research team reported that about 75% of people who received the Pfizer booster shot were protected. The team added, "Both Moderna and Pfizer vaccines have weakened immunity against the Omicron variant, but not to the extent of natural infection."

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