SINGAPORE - They are some of the fittest, fastest, strongest people in the world but Covid-19 does not discriminate and elite athletes have learnt this the hard way.
Precautions, protocols, and travel and competition bubbles have been put in place but some of the biggest names in sport have been among those infected since the pandemic began almost two years ago.
Singapore national football team captain Hariss Harun joined that list when he tested positive last week and his health and fitness is now under the microscope given the AFF Suzuki Cup - the region's biggest football tournament - kicks off on Dec 5.
On Wednesday (Nov 10), exactly a week after he first tested positive for Covid-19, the Football Association of Singapore (FAS) said in response to queries that Hariss is "recovering well".
The 30-year-old had a fever, blocked nose, body aches and headaches for two days and is currently in isolation under the Government's Home Recovery Programme.
"During this period, he has been put on a fitness programme to maintain his general body conditioning by the FAS, and in consultation with his club Lion City Sailors. This will prepare him to return to on-field training when he is discharged," said FAS' head of football science and medicine Haiyum Jaafar.
He noted that while the recommended time for a return to training is three to five weeks, Hariss has been healthy and maintaining his conditioning in isolation.
"We have strategised towards his return to the pitch by progressively increasing loading, specificity of actions and speed while being cautious that the tournament could potentially be a month-long one," said Haiyum.
Easing Hariss back into the intensity of international-level football is a delicate balancing act.
While there is evidence to suggest that elite athletes, who generally have higher base fitness levels and are healthier than the average person, may have stronger immune systems and recover quicker, there is a risk of returning to action too soon.
Some athletes who initially suffered a mild case of Covid-19 might later go on to suffer symptoms that last weeks or months, commonly referred to as "long Covid".
Welsh triathlete Chris Silver, 30, for example, only had mild symptoms when he first tested positive in March 2020 but returned to intense training too soon and this led to a 10-month battle with long Covid, the BBC reported.
British rower Oonagh Cousins, meanwhile, recovered from what she described as a "mild case" in February 2020, but as she was aiming for a place at the Tokyo Olympics kept up her intense training regimen. This, she told CNN, exacerbated the virus and she struggled to regain her full fitness even after over a year.
Dr Leong Hoe Nam, an infectious diseases specialist at Rophi Clinic said that factors such as an individual's genetic immune response and concomitant medical conditions play a part in whether an athlete will develop mid-to-long term physiological effects from a Covid-19 infection.
While he says it is reasonable to say young and healthy elite athletes such as Hariss may recover from the virus faster, Dr Leong added that the prospect of long Covid is a serious concern.
Asked how long Hariss might need to regain his full fitness, he said: "I suspect he will need one or two months… (but) it may be longer."
The FAS are more optimistic.
Haiyum noted that the timeline for return to elite sport for an athlete is determined by how mild, moderate or severe the case was.
"If an athlete only has mild illness or tests positive without experiencing any symptoms, they can consider returning to activity after the 10-day isolation period if they did not later develop symptoms," he said.
"Additional tests, including ECGs (electrocardiograms), heart imaging or blood work can also be performed to assuredly clear the athlete for their return to sport."
Hariss was forced to miss the national team's 10-day training camp in Dubai due to the positive test. The Lions left on Monday and will play two sparring matches before returning next Wednesday.
Hariss was on the mend from a quadriceps injury he picked up on the final day of the Singapore Premier League season on Oct 10, and was due to be cleared to return to full training on the same day he tested positive.
The midfielder, who has 101 caps for Singapore, will be one of the Lions' key players as they look to add to their four Suzuki Cup wins and first since 2012.
5 sports stars who recovered from Covid-19
Cristiano Ronaldo
The Portuguese football megastar tested positive in October 2020 while on international duty, and recovered after 19 days.
Lewis Hamilton
The seven-time Formula One world champion missed the Sakhir Grand Prix in December 2020 after he tested positive.
In August after the Hungarian Grand Prix, said he suspected he had "long Covid" as he felt dizzy and fatigued after the race.
Novak Djokovic
The world No. 1 men's tennis player tested positive in June 2020 following a heavily-criticised exhibition tournament he organised, which ended up hosting a cluster of cases.
Kevin Durant
The basketball star was one of the first National Basketball Association (NBA) players to test positive for the coronavirus in March 2020. The two-time NBA Finals most valuable player later said "the unknown was definitely difficult to deal with" but only had a mild case. He later helped the United States to a gold medal at the Tokyo Olympics in July.
Dustin Johnson
At the time the world's No.1 golfer, the American tested positive in Oct 2020 but also had mild symptoms. Just over a month later, he put on the famed Green Jacket after winning the Masters Tournament in Augusta.
