Corona: Triple contact with spike protein best protects against virus

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One question many people ask is: Do I still need to get vaccinated after getting covid 19? A new study says yes.

Protection against omicron

Only three contacts with the spike protein lead to good immunity – whether by infection or vaccination and regardless of the order. The antibodies formed are then not only present in sufficient quantity, but they are also able to neutralize new variants of concern (VOCs) such as currently Omicron.

Antibody response to coronavirus
Two vaccinations and a booster, one breakthrough disease after two vaccinations, or two vaccinations after one disease – in all these three cases, the study published in NatureMedecine demonstrated a high-quality antibody response of the immune system to coronavirus. A team led by Ulrike Protzer, head of the Institute of Virology at the Technical University of Munich, has followed more than 170 volunteers from among the staff at Klinikum rechts der Isar since the beginning of the pandemic. One group had been infected with SARS-CoV-2 in the first pandemic wave in spring 2020, while a second had not.

Later, both groups were offered vaccinations with BioNTech/Pfizer’s mRNA-based Covid-19 vaccine and followed up for nearly two years. Several parameters were determined in the blood of the subjects: the amount of antibody (IgG), the strength of binding between viral protein and antibody, and the ability of antibodies to neutralize SARS-CoV-2 variants in cell culture. The latter two are particularly important in estimating the extent of protective immunity.

Neutralization of virus
The study indicated that the immune system’s ability to neutralize virus is only partially correlated with antibody titer (amount). Rather, the decisive factor was how effectively these antibodies bind to the virus and thus inactivate it. This confirmed that Omicron “escapes” the immune system more easily than earlier variants. According to the study authors, this requires “significantly more and better antibodies to neutralize the virus.”

It showed “that people need three times contact with the spike protein for it to have very good neutralizing activity against all VOCs, including Omicron,” according to current knowledge.

Comparison of triple vaccinated people without infection with vaccinated recovered people.
Triple contact can occur in different constellations. Triple-vaccinated individuals without prior SARS-CoV-2 infection came close to equal titers of neutralizing antibodies to omicron as vaccinated recovered individuals or individuals who had breakthrough infection with delta or omicron. In all cases, neutralizing activity reached similarly high ranges in the analysis, and antibody binding strength increased in all constellations.