Alliance for Pandemic Preparedness

May 7, 2020

Repeated Seroprevalence of Anti-SARS-CoV-2 IgG Antibodies in a Population-Based Sample from Geneva Switzerland

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  • Researchers in Switzerland used a pre-existing representative survey of the population of Geneva to estimate SARS-CoV-2 seroprevalence. Each week, 1,300 participants not in quarantine or isolation were invited to participate, along with all members of the household 5 years or older. Over the first 3 weeks of the 12 week study, 1,335 participants were recruited (31% of those invited).  
  • Seroprevalence was estimated to be 3.1% (95% CI 0.2, 5.99) in week 1, 6.1% (95% CI 2.6, 9.33) in week 2, and 9.7% in week 3 (95% CI 6.1, 13.1). They found seroprevalence to be significantly higher in 5-19 year olds and 20-49 year olds compared to those >50 year olds. 
  • Despite increasing seroprevalence, these estimates show the population is far below the seroprevalence needed for herd immunity, assuming the presence of antibodies confers at least partial protection from infection. 

Stringhini et al. (May 6, 2020). Repeated Seroprevalence of Anti-SARS-CoV-2 IgG Antibodies in a Population-Based Sample from Geneva Switzerland. Pre-print downloaded May 7 from https://doi.org/10.1101/2020.05.02.20088898