In a recent development, it has come to light that 23 Chinese swimmers tested positive for the banned substance trimetazidine (TMZ) in the lead up to the Tokyo Olympic Games. However, these athletes were not sanctioned due to alleged contamination. The Chinese anti-doping agency (CHINADA) made this decision, which was later upheld by the World Anti-Doping Agency (WADA).

According to reports from the Herald Sun, the New York Times, and ARD, Germany's public broadcaster, more details have emerged about the source of the contamination and the disagreement among various anti-doping agencies regarding the handling of the situation. TMZ, a heart medication widely used outside the United States but not approved by the FDA for sale in the country, has been on WADA's list of banned substances since 2014.

Investigations conducted by CHINADA, as reported by ARD and the New York Times, revealed that the positive tests were traced back to the time when all the athletes were staying at the same hotel during the Chinese Long Course Invitational in Shijiazhuang City from December 31st, 2020, to January 3rd, 2021. Traces of trimetazidine were found in the extractor hood, spice containers, and drain of the hotel's kitchen. Despite seeking the assistance of China's national police, investigators were unable to determine how the drug got there but concluded that the swimmers had unwittingly ingested small amounts.

WADA stated that they were notified of CHINADA's decision in June 2021 and conducted their own review, including analyzing confidential documents, emails, the CHINADA report to WADA, and interviews with anti-doping experts. WADA concluded that they were unable to disprove the possibility of contamination being the source of TMZ ingestion, as it aligned with the analytical data in the case file. The consistently low concentrations of TMZ found in the athletes' samples, with no clear doping pattern, further supported the theory of unintentional ingestion, according to Professor Olivier Rabin, WADA Senior Director of Science and Medicine.

However, independent experts consulted by the New York Times expressed skepticism toward the theory that low concentrations of TMZ alone prove athletes ingested the substance unknowingly. They highlighted the possibility of other reasons for the low levels, such as being at the end of the drug's excretion period. While the experts disagreed on whether contamination was the most likely cause, they did not refute the theory provided by CHINADA.

This discrepancy in opinions has led to a dispute between anti-doping agencies. While WADA did not dispute CHINADA's findings and deemed an appeal unnecessary, other agencies such as the International Testing Agency (ITA) and the U.S. Anti-Doping Agency (USADA) disagreed. The ITA raised concerns over the reporting of the samples, and its investigation remains ongoing.

The handling of public disclosure has also been a point of contention. The positive test results from the Chinese swimmers were not reported to the computer management system until March 15, 2021, indicating a delay of two and a half months. CHINADA claimed that WADA had allowed them to freeze the tests for a month due to pandemic-related protocols. However, critics argue that any positive test for TMZ typically prompts immediate temporary suspension and public disclosure, which did not occur in this case.

Travis T. Tygart, CEO of USADA, strongly criticized the handling of the situation and called for accountability, stating that it was a betrayal to clean athletes. Interestingly, Tygart had previously expressed a different opinion regarding public disclosure in cases involving accidental ingestion of banned substances.

The controversy surrounding the positive drug tests of Chinese swimmers raises questions about the integrity of anti-doping protocols and the collaborative efforts between international anti-doping agencies. As investigations continue, it remains to be seen what actions will be taken to address the concerns raised and ensure fair competition in future sporting events.