Usain Bolt loses gold medal 8 years after his win. How common is that?

Jamaican sprinter Usain Bolt must surrender one of his nine Olympic gold medals because a sample taken from one of his teammates at the Beijing games more than eight years ago tested positive, upon re-analysis, for a prohibited stimulant, the International Olympic Committee (IOC) announced Wednesday.

Nesta Carter won gold with Mr. Bolt, Michael Frater, and Asafa Powell in the 4x100-meter relay, setting a world record of 37.10 seconds. After the IOC discovered methylhexaneamine in Mr. Carter's sample, however, all four competitors must return their gold medals. And they're not alone. So far, more than 100 Olympic athletes from Beijing in 2008 and London in 2012 have tested positive in re-tests, once again highlighting how pervasively doping scandals have threatened international sports.

The problem has been the subject of a social media campaign to raise awareness with selfies and temporary tattoos, accompanied by persistent calls for stricter enforcement and harsh penalties.

"Illegal drug-doping damages the concept of fair play that beats at the heart of any sports competition," The Christian Science Monitor's editorial board wrote last month. "Unless it can be curtailed, it will threaten to leave a cloud of cynicism looming over some of the world's greatest sporting events."

Bolt and Carter will keep their gold medals from their 2012 relay win, when they set the current record time of 36.84 seconds. 

Carter, who faces a ban from the International Association of Athletics Federations (IAFF), did not compete last year in the Rio de Janeiro Olympics, where Bolt – a crowd-pleasing celebrity in his own right – went on to win his seventh, eighth, and ninth gold medals.

During an IOC disciplinary hearing in October, Carter testified via video conference that he had taken supplements in 2008 on the advice of his coach, Stephen Francis.

"The athlete explained that he had given several samples for doping controls whilst he was taking Cell Tech and Nitro Tech before the 2008 Olympic Games and he had never tested positive for a prohibited substance," the IOC's detailed verdict stated, as Reuters reported. "He therefore did not believe that these supplements could contain prohibited substances."

Carter also did not understand how the stimulant could have been found eight years later, the verdict notes. As testing capabilities improve, the IOC program has revisited old samples to find traces of drugs that were undetectable in 2008 or 2012.

Although methylhexaneamine was not specifically listed among prohibited substances in 2008, it "fell within the scope of the general prohibition of stimulants having a similar chemical structure or similar biological effect as the listed stimulants," the three-member IOC panel wrote. The substance has been on the World Anti-Doping Agency (WADA) Code prohibited list since 2004, but it was reclassified as a "specified substance" in 2011.

As a result of the IOC's findings, Trinidad and Tobago's team is in line to receive gold medals for their 2008 performance, with Japan's possibly being bumped up to silver. Brazil, which finished in fourth place, could receive bronze medals.

Separately, the IOC stripped another Olympic medalist of two silver medals Wednesday. Tatiana Lebedeva, of Russia, tested positive for an anabolic steroid, upon re-analysis, disqualifying her for her second-place performance in the long jump and triple jump competitions in Beijing. 

Doping by Russian athletes, with government backing, has proven to be such a major problem for international sports competitions that it has intersected with global politics, as Monitor correspondent Fred Weird reported last summer from the Russian capital:

Western experts argue that only the 'nuclear option' of a total ban on Russian participation for at least one Olympic cycle will help to focus minds in Moscow. That, they say, would compel the state-run sports establishment to initiate the ground-up reforms needed to end what they call a culture of systemic doping in all branches of Russian sport, aided and abetted by government and security forces.

Russian experts argue that a blanket ban will have a negative impact on the public, and be easily represented by state TV – the primary information source for most Russians – as just another front in the West's campaign to sanction and delegitimize Russia. 

Despite the obstacles, the push to reform athletics, even in Russia, is not a lost cause, says Alexei Dospekhov, a sports writer for the Moscow daily Kommersant.

"This is possible," Mr. Dospekhov told the Monitor in July. "No matter how it is portrayed in the West, the fact is that some Russian sports have been quite effective in resisting doping, and creating systems to ensure their people are clean."

This report includes material from Reuters and the Associated Press.