10 Dec 2023

Lisa Sanders: How many people end up with Long Covid?

From Sunday Morning, 9:40 am on 10 December 2023
New species of corona virus covid 19 micro cell, 3d rendering

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There is still much to learn about Long Covid, but a Yale researcher says she hopes it will eventually be one of the many diseases that are able to be "well managed and treated".

"Cure is a funny word," Dr Lisa Sanders told RNZ's Sunday Morning.

"There are lots of diseases that are very well treated and very well managed but aren't cured and if ... Long Covid were to turn out to be one of them I would be thrilled."

The international consensus is that one in 10 people who get Covid-19 will feel long-lasting effects.  

New Zealand is currently experiencing its fifth wave of the virus, with roughly 900 cases being reported every day, meaning around 100 of those people will not get over the virus anytime soon.

Sanders, who has spoken to RNZ previously about her Long Covid research, said there were still many more unknowns than knowns about how and why the disease affected people.

"What we don't know about Long Covid so overwhelms what we do know," she said.

"We do this one patient at a time and hopefully we've helped some patients since we saw you last."

While some research seemed to point to women being at greater risk of developing Long Covid than men, Sanders said she had not observed women greatly outnumbering men at her own laboratory.

"I think that women are at higher risk of Long Covid although you have to understand that since there's no test for Long Covid what we really know is that women go to see their doctors about Long Covid more than men go to see their doctors about Long Covid," she said.

"I think probably women have it more because women have a lot of things more. I don't think it's wrong to say that we have more complicated bodies than men and are more subject to a lot of things."

Asked about an article in New Scientist which suggested that the fatigue and brain fog symptoms associated with Long Covid might be connected to plummeting levels of certain hormones, Sanders said: "It certainly makes sense."

People with Long Covid tended to have lower cortisol levels than normal, she said.

"I've seen that with some of my Long Covid patients, not all of them."

Low serotonin levels had also been seen in patients with Long Covid, she said, though more research was required to understand "whether low serotonin levels is the cause of the symptom or the product of the symptom or completely unrelated".

"Diseases can affect our bodies in a lot of ways so maybe this is a way that has no clinical relevance, we don't know," she said.

"We know that Covid can cross the blood-brain barrier ... and we know that Covid can cause changes in mood and cause mood disorders, but I'm not sure how it all wraps together. It would be nice if the low serotonin level told us something about what was happening in the brain - I look forward to those answers."

One study which caught Sanders' attention and had driven her to begin trialling a new treatment with her patients was an intervention that touted the use of vitamin C in combination with the amino acid l-arginine.

"The reason I even heard about it was that there was this very rigorous meta analysis and ... report published by what seems to me to be the Irish equivalent of the NIH - the National Institute for Health - that looked at as many of the Long Covid treatments that they thought ... merited being looked into."

While most of the interventions analysed appeared not to have worked "l-arginine plus vitamin C was one of the few things that this panel thought cut the mustard in ... studies that had been published, so I thought that was a pretty good recommendation".

Sanders confessed she had not actually read the original study referenced in the report yet, but said she had read the meta analysis, which she trusted "because they were so rigorous about everything else".

She had begun using the treatment on her patients at the end of July, but it would take time to assess whether it was effective or not, she said.

"It's not like people are throwing away their canes and running up and embracing me so you know, I don't think it's a miracle cure, but the jury's still out on whether it has any effectiveness at all."

Another unknown for now is exactly how the Covid-19 virus causes Long Covid in the first place.

It was possible it behaved in a similar manner to some forms of herpes viruses like Epstein-Barr and shingles, she said.

"Maybe Covid does that and hangs around ... just lurking around the corners, or maybe it's broken up into fragments and those fragments do things, or maybe it passes through our body and does all sorts of damage and changes all sorts of settings and things and then passes out and we're just left with the ruin."

"We don't know yet," she said, adding it could be different for different people.

"We still have a way to go."