Repeated Omicron exposures override ancestral SARS-CoV-2 immune imprinting. (https://www.nature.com/articles/s41586-023-06753-7)
These scientists wanted to study how our immune system responds to different versions of the virus that causes COVID-19. They were particularly interested in a new version of the virus called Omicron. They found that if we have been vaccinated with an older version of the virus, our immune system might not respond as well to the Omicron version.
To understand this better, the scientists studied mice and people who had been infected with the Omicron virus multiple times. In mice, they found that a single Omicron booster shot was not very effective if the Omicron version was different from the older version they were vaccinated against. But when the mice received a second Omicron booster, their immune response improved.
In humans, the scientists found that repeated Omicron infections could also help our immune system respond better to the virus. They studied the blood and nasal mucus of people who had been infected with Omicron multiple times and found that their immune system produced antibodies that could neutralize the virus.
The scientists also looked closely at the antibodies produced by the immune system. They discovered that the antibodies from repeated Omicron infections were different from the ones produced by the older version of the virus. These new antibodies were better at fighting off the Omicron version.
Based on their findings, the scientists suggest that when updating COVID-19 vaccines, we should not include the older version of the virus. Instead, people who have not been infected with Omicron before should receive two updated vaccine boosters to help their immune system respond better to the virus.
Yisimayi A., Song W., Wang J., Jian F., Yu Y., Chen X., Xu Y., Yang S., Niu X., Xiao T., Wang J., Zhao L., Sun H., An R., Zhang N., Wang Y., Wang P., Yu L., Lv Z., Gu Q., Shao F., Jin R., Shen Z., Xie XS., Wang Y., Cao Y. Repeated Omicron exposures override ancestral SARS-CoV-2 immune imprinting. Nature. 2024 Jan;625(7993):148-156. doi: 10.1038/s41586-023-06753-7. Epub 2023 Nov 22.