WADA on contamination case involving Chinese swimmers
Fact Sheet / Frequently Asked Questions
Between 1 and 3 January 2021, the China Anti-Doping Agency (CHINADA) collected 60 urine samples of Chinese swimmers at a national swimming meet. There were 201 swimmers competing. This event was not a qualifying event for the Olympic Games.
After certain delays due to the COVID-19 pandemic, the samples were reported into WADA’s Anti-Doping, Administration and Management System (ADAMS) by the WADA-accredited laboratory in Beijing on or around 15 March 2021.
There were 28 Adverse Analytical Findings (AAFs) for the prohibited substance, trimetazidine (TMZ), involving 23 different swimmers, which means that a small number of them tested positive more than once.
In early April 2021, CHINADA informed WADA that it had initiated an investigation, involving the public health authorities, into the source of TMZ found in the samples.
There were strong indicators that these cases could be a case of group contamination considering the following factors:
- There were 23 swimmers, and 28 positive samples. All tested positive at the same time for TMZ at consistently very low levels (pg or low ng/mL range).
- The swimmers were from different regions of China, with different coaches and from different swimming clubs.
- The swimmers were in the same place at the same time when the positive samples arose.
- A number of these swimmers were tested on multiple occasions during the swim meet. Some of them were tested on two or even three occasions on consecutive days.
For several swimmers, the results varied from negative to positive within a few hours, which is not compatible with a doping scenario of deliberate ingestion nor with micro-dosing.
Some of the competing swimmers stayed in at least one other hotel. Three of those athletes were tested and none tested positive for TMZ.
Between January and June 2021, there were no international swimming competitions scheduled. Therefore, these athletes did not participate in any such competitions during that time period.
Further WADA documents regarding the Chinese swimming case are available here: Key documents regarding Chinese swimming case | World Anti Doping Agency
