This is a summary, written by members of the CITF Secretariat, of:

Galipeau Y, Siragam V, Laroche G, Marion E, Greig M, McGuinty M, Booth RA, Durocher Y, Cuperlovic-Culf M, Bennett SAL, Crawley AM, Giguère P, Cooper C, Langlois M-A. Relative Ratios of Human Seasonal Coronavirus Antibodies Predict the Efficiency of Cross-Neutralization of SARS-CoV-2 Spike Binding to ACE2. EBioMedicine 2021 Dec.; doi:

The results and/or conclusions contained in the research do not necessarily reflect the views of all CITF members.

Nearly everyone has been exposed to the highly prevalent seasonal coronaviruses responsible for the common cold. But could this exposure induce antibodies that also recognize certain proteins of the SARS-CoV-2 virus? A study led by University of Ottawa researcher Dr. Marc-André Langlois, now published in EBio Medicine, proposes that some individuals previously infected with certain seasonal coronaviruses may have pre-existing protective immune responses against SARS-CoV-2.

Key points: 

  • Researchers used samples collected prior to 2019, ensuring no exposure to SARS-CoV-2. Of the 580 samples examined, the majority were positive for IgG antibodies against proteins from the seasonal coronaviruses OC43, NL63, and 229E (83%, 75%, and 82% respectively).
  • While less than 5% of these pre-pandemic samples reacted against the SARS-CoV-2 spike protein, 7 to 15% reacted to the SARS-CoV-2 nucleocapsid protein. This can be explained by antibody ‘cross-reactivity’ as these individuals were not exposed to the SARS-CoV-2 virus at the time of sample collection. Antibody cross-reactivity is due to antibodies recognizing areas that are similar between proteins from different coronaviruses.
  • Of the many different seasonal coronaviruses, previous exposure to NL63 seems to be associated with a greater ability to neutralize the interaction between the SARS-CoV-2 spike and its cellular receptor, ACE2.
  • Aside from antibodies, other variables yet to be identified (such as cell-mediated immunity from prior exposures) may also be involved in protection against SARS-CoV-2.