must be taken when 
interpreting these data as several factors influence the counts presented, with variable underestimation o f true case and 
death incidences, and variable delays to reflecting these data at the global level. Case detection, inclusion criteria, testi ng 
strategies, reporting practices, and data cut -off and lag times differ between countries/territories/areas.  Dif ferences are 
to be expected between information products published by WHO, national public health authorities, and other sources.  
A record of historic data adjustment is available upon request by emailing epi-data -support@who.int . Please specify the 
countries of interest, time period, and purpose of the request/intended usage. Prior situation reports will not be edited; 
see covid19.who.int  for the most up -to-date data.  
‘Countries’ may refer to countries, territories, areas or other jurisdictions of similar status. The  designations employed, 
and the presentation of these materials , do not imply the expression of any opinion whatsoever on the part of WHO 
concerning the legal status of any country, territory, or area or of its authorities, or concerning the delimitation of its 
frontiers or boundaries. Dotted and dashed lines on maps r epresent approximate border lines for which there may not 
yet be full agreement. Countries, territories, and areas are arranged under the administering WHO region. The mention 
of specific companies or of certain manufacturers’ products does not imply that they are endorsed or recommended by 
WHO in preference to others of a similar nature that are not mentioned. Errors and omissions  excepted;  the names of 
proprietary products are distinguished by initial capital letters.  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  
26 
 Annex 2. SARS -CoV-2 variants assessment and classification  
 
WHO, in collaboration with national authorities, institutions and researchers, routinely assesses if variants of S