COVID-19 mRNA vaccine induced antibody responses against three SARS-CoV-2 variants

Jalkanen, Pinja; Kolehmainen, Pekka; Häkkinen, Hanni K.; Huttunen, Moona; Tähtinen, Paula A.; Lundberg, Rickard; Maljanen, Sari; Reinholm, Arttu; Tauriainen, Sisko; Pakkanen, Sari H.; Levonen, Iris; Nousiainen, Arttu; Miller, Taru; Välimaa, Hanna; Ivaska, Lauri; Pasternack, Arja; Naves, Rauno; Ritvos, Olli; Österlund, Pamela; Kuivanen, Suvi; Smura, Teemu; Hepojoki, Jussi; Vapalahti, Olli; Lempainen, Johanna; Kakkola, Laura; Kantele, Anu; Julkunen, Ilkka

As SARS-CoV-2 has been circulating for over a year, dozens of vaccine candidates are under development or in clinical use. The BNT162b2 mRNA COVID-19 vaccine induces spike protein-specific neutralizing antibodies associated with protective immunity. The emergence of the B.1.1.7 and B.1.351 variants has raised concerns of reduced vaccine efficacy and increased re-infection rates. Here we show, that after the second dose, the sera of BNT162b2-vaccinated health care workers (n = 180) effectively neutralize the SARS-CoV-2 variant with the D614G substitution and the B.1.1.7 variant, whereas the neutralization of the B.1.351 variant is five-fold reduced. Despite the reduction, 92% of the seronegative vaccinees have a neutralization titre of >20 for the B.1.351 variant indicating some protection. The vaccinees’ neutralization titres exceeded those of recovered non-hospitalized COVID-19 patients. Our work provides evidence that the second dose of the BNT162b2 vaccine induces cross-neutralization of at least some of the circulating SARS-CoV-2 variants.