| | Country | Papers | Citations | Citations per paper |
| 1 | Switzerland | 3,837 | 108,908 | 28.38 |
| 2 | United States | 55,074 | 1,461,855 | 26.54 |
| 3 | Ireland | 590 | 14,821 | 25.12 |
| 4 | Japan | 10,221 | 237,878 | 23.28 |
| 5 | England | 11,399 | 262,911 | 23.06 |
| 6 | Germany | 10,495 | 239,466 | 22.82 |
| 7 | France | 8,549 | 191,342 | 22.38 |
| 8 | Scotland | 1,649 | 36,370 | 22.06 |
| 9 | Australia | 4,894 | 104,509 | 21.35 |
| 10 | The Netherlands | 4,936 | 104,770 | 21.23 |
| 11 | Canada | 5,475 | 115,947 | 21.18 |
| 12 | Austria | 1,659 | 33,642 | 20.28 |
| 13 | Belgium | 2,134 | 42,801 | 20.06 |
| 14 | Israel | 1,752 | 34,882 | 19.91 |
| 15 | Italy | 6,258 | 124,195 | 19.85 |
| 16 | Finland | 1,306 | 24,229 | 18.55 |
| 17 | Denmark | 2,004 | 35,901 | 17.91 |
| 18 | South Africa | 906 | 16,113 | 17.78 |
| 19 | Sweden | 4,433 | 75,142 | 16.95 |
| 20 | Norway | 1,223 | 20,397 | 16.68 |
The data above were extracted from the Essential Science Indicators database of Thomson Reuters.
This database, currently covering the period January 1999 to October 2009, surveys only journal articles (original research reports and review articles) indexed by Thomson Reuters. Articles are assigned to a category based on the journals in which they were published and the Thomson Reuters journal-to-category field-definition scheme. Both articles tabulated and citation counts to those articles are for the period indicated.
Here our ranking in immunology is by citations per paper among nations that collected 10,000 or more citations during the period to reveal weighted impact. For articles with multiple authors from different nations, each nation receives full, not fractional, credit. Essential Science Indicators lists nations ranked in the top 50 per cent for a field over a given period, based on total citations.
In immunology, 91 nations are listed, meaning 182 were surveyed. Twenty-eight nations collected at least 10,000 citations. Of particular interest is the outstanding performance of Ireland, which ranks third by citation impact despite its relatively small output. Researchers at Trinity College Dublin published eight of nine highly cited Irish papers in the field: of these, seven were written by Luke O’Neill, a professor at Trinity’s School of Biochemistry and Immunology. Professor O’Neill, who focuses on innate immunity and inflammation, recently received the Science Foundation Ireland Researcher of the Year Award and the Royal Dublin Society-Irish Times
2009 Boyle Medal in recognition of his influential research.
For more information, see http://scientific.thomsonreuters.com/products/esi