Cell Reports (Dec 2023)

Characterization of a SARS-CoV-2 EG.5.1 clinical isolate in vitro and in vivo

  • Ryuta Uraki,
  • Maki Kiso,
  • Kiyoko Iwatsuki-Horimoto,
  • Seiya Yamayoshi,
  • Mutsumi Ito,
  • Shiho Chiba,
  • Yuko Sakai-Tagawa,
  • Masaki Imai,
  • Yukie Kashima,
  • Michiko Koga,
  • Noriko Fuwa,
  • Nobumasa Okumura,
  • Masayuki Hojo,
  • Noriko Iwamoto,
  • Hideaki Kato,
  • Hideaki Nakajima,
  • Norio Ohmagari,
  • Hiroshi Yotsuyanagi,
  • Yutaka Suzuki,
  • Yoshihiro Kawaoka

Journal volume & issue
Vol. 42, no. 12
p. 113580

Abstract

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Summary: EG.5.1 is a subvariant of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron XBB variant that is rapidly increasing in prevalence worldwide. However, the pathogenicity, transmissibility, and immune evasion properties of isolates of EG.5.1 are largely unknown. Here, we show that there are no obvious differences in growth ability and pathogenicity between EG.5.1 and XBB.1.5 in hamsters. We also demonstrate that, like XBB.1.5, EG.5.1 is transmitted more efficiently between hamsters compared to its predecessor, BA.2. In contrast, unlike XBB.1.5, we detect EG.5.1 in the lungs of four of six exposed hamsters, suggesting that the virus properties of EG.5.1 are different from those of XBB.1.5. Finally, we find that the neutralizing activity of plasma from convalescent individuals against EG.5.1 was slightly, but significantly, lower than that against XBB.1.5 or XBB.1.9.2. Our data suggest that the different virus properties after transmission and the altered antigenicity of EG.5.1 may be driving its increasing prevalence over XBB.1.5 in humans.

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