'She's the strongest person I know': Twin sprinters Lina and Laviai Nielsen's experiences with MS

Lina and Laviai Nielsen are identical twin sisters and are both sprinters. Stephen Pond - British Athletics/British Athletics via Getty Images

BIRMINGHAM, England -- Every time Lina Nielsen finishes a race, the same thought runs through her head. "Look what you did," she says to herself. "It's crazy." She has a good reason to tell herself that, too.

The past week has been a whirlwind for British sprinter Nielsen, one of the best 400m hurdles athletes in the world. On Wednesday, she revealed in an interview that she has multiple sclerosis -- a lifelong condition that affects the brain and spinal cord and which can cause problems with vision, movement and balance -- and has since she first showed symptoms aged 13, or for over half of her life. Only a handful of people knew: her family, close friends, teammates. "Everyone that needed to know, knew," she said. Yet this is not her first big revelation. That came when she told her identical twin sister, Laviai.

Lina, officially diagnosed with MS just before her 18th birthday, kept it from Laviai. It was two months before she was able to tell her. They were travelling in the back of a car.

"What's that?" Laviai asked, as most teenagers would do. Lina described what MS was, and said that was the reason she sometimes couldn't control her fingers and why she occasionally couldn't walk, or why she sometimes suffered from double vision.

But Lina had one more thing to tell her identical twin sister which had been playing on her mind and fueling her sense of guilt. It was the reason she hadn't told Laviai in the first place.

"Sorry," she started, "but as an identical twin, you might have to go through this as well."

Lina and Laviai, both world class British sprinters, are inseparable. They always have been.

"We don't have any other siblings, so we've always been incredibly close," Laviai told ESPN. "We're best friends, and it's great to always have someone who understands you day in, day out. It's a very deep level of understanding. I can walk into a room and instantly understand what her mood is like. That is really helpful when it comes to her condition."

It was Laviai that was always there for Lina when she suffered her relapses. She was there aged 17, when the condition caused Lina paralysis on her right side, with Laviai brushing her sister's hair before school, or helping her to brush her teeth. She was also there for her in a hotel room in Eugene, Oregon, during last month's World Championships, when Lina suffered her first relapse in five years. It was the day before Lina's heat at the biggest event of her career.

"I could tell something was wrong," Laviai says. "I just got that feeling, I could see something was up.

"She was really quiet and reserved and looked a bit washed out. I didn't want to think the worst, but I thought maybe it was nerves or stress. She told me, 'I can't feel my torso.' I haven't heard those words come out of her mouth in five years, and she had a World Championship race the next day."

The numbness Lina had felt waking up had progressed by the time of her race, with her left arm and most of her left leg feeling numb. She also had weakness on her right side.

"I felt every emotion she felt," Laviai said. "When she was upset, I was upset; when she cried, I cried; when she was nervous, I was nervous."

Laviai, as always, was there by her side. She travelled to the stadium with her sister, who was growing worried that she might fall over on the track during perhaps the biggest meet of the year. And then she watched as Lina pushed through, ran her race and finished last.

It was a major disappointment, but it also set in motion the public revelation that was to come. When Lina returned home to London, she processed what had happened and decided it was time to tell others and hopefully inspire others with MS. That included her sister.

Laviai has known for nine years that there was a good chance she would have MS, too.

"I kind of always hoped that she didn't have to go through it," Lina said. "If you follow our Instagram, we live a very healthy lifestyle, always eating healthy food. So I'd be like 'Make sure you take your Vitamin D, make sure you do this, make sure you take your Omega 3, do this, don't do this.' I really don't want her to go through that."

But that could not stop it. Last July, when Laviai had the COVID-19 vaccine and her arm tingled for longer than it should have, she asked Lina if she thought it could be MS. Her sister said it likely wasn't but tests revealed a tiny lesion, a sign of MS. Soon after, she was given an early diagnosis for the condition.

"We've caught it at a very early stage, so I think Lina's MS is very different," Laviai said. "I just had what I would describe as a dead arm last year.

"It was because I was able to catch it early and start treatment early [that I have such few symptoms]."

Taking the news public has been a very personal experience for Lina, who raced again at the Commonwealth Games this week, although she did not reach the final as she continues to recover from her latest relapse. She said she has not processed fully what it means for her, or others with the condition, many of whom have sent her messages calling her an "inspiration" or a "warrior."

Lina intends to get back to all of them, knowing how much effort it takes to reach out. The messages have only confirmed to the world what Laviai has known all along.

"I've been seeing all the comments she's gotten and been nodding my head," Laviai said. "I know all this more. She's an incredible woman, the strongest person I know."