The researchers further investigated whether patients infected in Germany during the first wave of the pandemic had produced antibodies that protect against the Omicron variant.While the antibodies inhibited the spike of the virus responsible for the first wave, the researchers had little effect against the Omicron spike.They assume that these individuals do not have robust immune protection against the Omicron variant, although an inhibition by T cells, which are also produced during infection, remains to be analysed.Antibodies produced after two immunisations with the Pfizer vaccine also inhibited the Omicron spike significantly less efficiently than the spike proteins of other variants, the researchers said.A better protective effect was observed after three doses with Pfizer and after heterologous immunisation with AstraZeneca and Pfizer preventives, they said.These results indicate that dual immunisation with Pfizer may protect less efficiently against the Omicron variant as compared to the Delta variant, according to the study.Triple immunisation with Pfizer (booster) and cross-vaccination with AstraZeneca/Pfizer could establish stronger protection, it found.”Our results indicate that antibody therapies for COVID-19 need to be adapted to the Omicron variant. Adaptation of the BioNTech-Pfizer vaccine should also be considered,” said Hoffmann.”In contrast, triple immunisation with BioNTech-Pfizer (booster) and cross-vaccination with Oxford-AstraZeneca,” Hoffmann added.
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