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Each person has their own coronavirus “history book”, whether they are unvaccinated, (partially) vaccinated, and/or naturally infected with one or more coronavirus strains. A recent study published in elaborates on how your coronavirus history can affect your protection against new coronavirus variants in the future.

A team of scientists from Imperial College London and Queen Mary ľ�ϸ���Ӱ�� of London found that each variant raises distinct immune responses. As a result, your immune system is wired differently depending on which viral strain you encountered first. This wiring of your immune system is called “immune imprinting”. The researchers in Science found that previous encounters with other strains affects how your body reacts to a new variant.

As you may know, our current vaccines against the coronavirus are based on the virus strain that first appeared in Wuhan, China in December 2019. More specifically, it is based on its spike protein, which the virus uses to enter human cells. After escaping Wuhan, the spike protein mutated, giving rise to new variants. First alpha, then beta, gamma, delta, and recently omicron.

The study followed 731 healthcare workers since March 2020. Some had been infected with the original corona strain in the first wave and some with the alpha variant in the second wave. Additionally, all healthcare workers had received two doses of the Pfizer/BioNTech vaccine. Hence, participants had either been in contact with three similar spike proteins (homogeneous encounters) or three different spike proteins (heterogeneous encounters).

People with heterogeneous spike encounters showed a lower protective antibody response to the original strain and beta variant, but a higher antibody response to the delta variant compared to people with homogeneous spike encounters.

The researchers compared the protective immunity acquired by these groups by looking at antibody responses. Antibodies are molecules in the immune response that recognize the virus and subsequently put the immune system to work. People with heterogeneous spike encounters showed a lower protective antibody response to the original strain and beta variant, but a higher antibody response to the delta variant compared to people with homogeneous spike encounters. The researchers also found that the levels of antibodies, and therefore protection, decreased at different rates for each strain.

Since people may have encountered different variants more or less often distinct “history books” or immune imprints exist within society. Moreover, these history books will become even more unique with each new variant. As a consequence, the “owners” of particular history books will have a specific reaction upon encountering a new variant in the future.

This is something to take into account in the development of new vaccines. It is attractive to make this vaccine as efficient as possible against the dominant variant at that time. However, based on the findings of this research, the vaccine should be optimized differently. The vaccine should optimally complement the already existing immune imprints and therefore responses in society. In this way, we are better protected against the pi, rho, and sigma variants of the future.