In a new study from Ohio State University, researchers found neutralizing antibody levels produced by two-dose mRNA vaccines against the original and early variants of the SARS-CoV-2 virus wane substantially over time, and offer essentially no protection against the Omicron variant.
They that a third COVID-19 mRNA vaccine booster shot did produce effective levels of neutralizing antibodies against Omicron.
In the study, the team examined antibodies in serum samples from 48 health care professionals with experimental versions of the parent virus and the alpha, beta, delta and Omicron variants.
Serum samples were collected pre-vaccination, three to four weeks after a first vaccine dose, three to four weeks after a second vaccine dose and six months after the second vaccine.
The team found there was a substantial increase in neutralizing antibodies after the second dose against every variant except the Omicron variant
From the second dose to six months later, there was an at least five-fold drop in immunity, even against the parent virus.
Neutralizing antibodies that block viral particles’ entry into host cells are considered the gold standard of protection against COVID-19 infection.
Twelve of the samples came from people suspected to have had a COVID-19 infection—at time points ranging from before vaccination to after two vaccine doses—based on a different kind of antibody testing.
And though the findings suggested a breakthrough COVID-19 infection on top of vaccination increased immunity against most versions of the virus, antibodies from only one individual with the previous infection reached levels that could put up a reasonable fight against Omicron.
Overall, nobody in this study had good immunity against Omicron.
The team also showed that people who received the Pfizer-BioNTech mRNA vaccine produced about two-fold lower levels of neutralizing antibodies than those who received the Moderna vaccine.
Men also had much higher antibody levels compared to women against all variants over the post-vaccination time points.
Liu said the dramatic reduction in immunity six months after two vaccine doses and the earlier paper’s finding that a booster protects against Omicron highlight how important a third shot is to avoiding infection.
If you care about COVID, please read studies that Pfizer booster more than 50% protective against omicron, and common drugs for heart disease, prostate cancer, high cholesterol may treat COVID-19.
For more information about COVID, please see recent studies that Omicron makes booster shots more critical for medically vulnerable seniors, and results showing that COVID booster shot can cut your death risk by 90%.
The study is published in Science Translational Medicine and was conducted by Shan-Lu Liu et al.
Copyright © 2022 Knowridge Science Report. All rights reserved.
