“Solidarity II” global serologic study for COVID-19

“Solidarity II” global serologic study for COVID-19

National Institute of Allergy and Infectious Diseases (NIAID)
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“Solidarity II” global serologic study for COVID-19

Solidarity II is a global collaboration led by the World Health Organization that promotes the implementation of serological surveys of SARS-CoV-2.  Solidarity II provides a collaborative environment for public health agencies and academic institutions around the world to work together to answer some of the most urgent questions about the COVID-19 pandemic.  Understanding the occurrence of infection with SARS-CoV-2 infection is critical for the world to know how frequently infection occurs among different populations, how many people have had mild or asymptomatically infection, how many people have been infected but may not have been identified by routine disease surveillance, and what proportion of the population may be immune from infection by SARS-CoV-2 in the future.  



To join the Solidarity II Collaboration and work together on this shared global challenge

Email us: solidarity2@who.int


A complete understanding of the epidemiology and global risk posed by SARS-CoV-2 requires systematic serologic testing.  Serologic testing detects antibodies in the blood that indicate if a person has already been infected.  By conducting surveys among different populations around the world, we can together understand the extent of the COVID-19 pandemic, which in turn will allow local, national, and international decision-makers to respond collectively to the pandemic.

Unique features of Solidarity II are that it provides a global platform for government and academic collaborators to share cutting-edge scientific advances in the area of serologic surveys; accelerates progress globally towards understanding the COVID-19 pandemic; provides every country access to the tools and procedures needed to conduct their own serologic surveys; and promotes access to scientific discovery for all populations globally.  



Scientific breakthroughs

A laboratory technician running tuberculosis text on a machine

Scientific breakthroughs that are being achieved by Solidarity II include:

  • The global sharing of well characterized panels of sera to enable standardization of serologic assays worldwide;
  • Facilitated access to high-quality antigen specifically for assays to conduct serologic surveys;
  • Development of a standardized serology assay for collaborators who wish to use a global standard;
  • Methodologies for laboratories around the world to develop their own serologic assays, if desired;
  • Laboratory protocols for the use of serologic assays for the purposes of serology surveys;
  • Promote sharing of study protocols, such as the Unity protocols from WHO
  • Support with analysis of individual serologic surveys;
  • A meta-analysis of findings across surveys from collaborators to provide a global understanding of sero-prevalence and sero-incidence of SARS-CoV-2, and the potential impact of different control measures.
  • A global research database and collaborative work space for the sharing of scientific protocols, training materials; scientific publications; survey findings, and other information for Solidarity II Collaborators.



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