Two years ago today, I was in the midst of my eighth-straight week of Covid-19 misery, wondering what the hell was wrong with me, and why, instead of recovering, I continued to accumulate new symptoms. In addition to those that had been with me from the very beginning — shortness of breath, muscle aches, debilitating exhaustion, chills — my collection expanded to include rashes, hair loss, and multiple neurocognitive symptoms that have since been lumped together and labeled “brain fog.” Complete inadequacy of the term aside, the word “fog” implies that it’s temporary, and soon will lift.

But the results of a study published today in the journal Annals of Clinical and Translational Neurology tell a different story: that some people with Long Covid continue to experience neurological symptomsincluding cognitive dysfunction, fatigue, headaches, and dizziness — more than a year after their initial Covid-19 infection.

These findings are the latest insights from Igor Koralnik, MD, chief of neuro-infectious diseases and global neurology at Northwestern Medicine, and his team at the hospital’s Neuro Covid-19 Clinic. Their previous study, published in March 2021, reported that 85 percent of the Clinic’s Long Covid patients who sought treatment between May and November 2020 (after relatively mild Covid-19 illnesses that didn’t require hospitalization) had a minimum of four neurological symptoms.

When Koralnik and his colleagues followed up with the same group of patients between 11 and 18 months after their initial Covid infection — the results of which were published today — 81 percent indicated that they were still dealing with at least one neurological symptom; most had several. Of the 52 participants in this arm of the study, the average age was 43, and 73 percent identified as female.

“The main takeaway [from this study] is that patients [an average of] 15 months from disease onset still had a persistence of the most debilitating neurological symptoms, including brain fog, headache, dizziness, fatigue, blurred vision, and ringing in their ears,” says Koralnik, adding that the only symptoms patients reported decreasing over time were the loss of taste and smell.

Adam Kaplin, MD, PhD, a neuropsychiatrist who has worked with Long Covid patients as part of the Johns Hopkins Post-Acute Covid-19 Team and was not involved with the Northwestern study, says that its findings “should absolutely be a wake-up call,” highlighting the fact that these persistent neurological symptoms aren’t limited to those who were hospitalized with life-threatening Covid-19 infections, and include people whose initial illnesses weren’t as severe, “who were just minding their business at home trying to recover.”

Interestingly, the study also found that three symptoms — variation in heart rate and blood pressure, and gastrointestinal issues — became more frequent over time, which Koralnik says suggests that Long Covid may be triggering abnormal autoimmune reactions in some patients, causing their body to attack its own healthy cells. “We know that 16 percent of [participants in our study] had autoimmune disease before Covid, which is higher than the normal U.S. population,” he tells Rolling Stone. “And there may be an autoimmune predisposition in the patients who develop Long Covid.” 

Kaplin suggests another possible explanation for the emergence of these cardiovascular and gastrointestinal symptoms, pointing out that they are all potential side effects of medications used to treat other Long Covid symptoms like depression, anxiety, and sleep disturbances. “I’m not quite sure how to interpret the symptoms that didn’t exist and got worse, because [the authors of the study] didn’t clarify who was on what meds,” he tells Rolling Stone.

The research also shed light on how vaccines may impact Long Covid. With 77 percent of the study’s participants fully vaccinated, Koralnik says that vaccination had a neutral effect. 

Like everyone else, people with Long Covid may experience short-term side effects after receiving a dose of the vaccine, typically lasting between 24 and 48 hours. “Sometimes people [with Long Covid] say [the vaccine causes] a reawakening of some of their symptoms,” Koralnik explains. “But Long Covid is not triggered by vaccination or made worse by vaccination over time, and the benefits of vaccination are far greater than the inconvenience of a transient reaction to the vaccine.”

According to Koralnik, this research has “the longest follow-up period of neurologic symptoms impacting non-hospitalized patients who developed Long Covid anywhere in the world.” And while Kaplin recognizes the importance of the findings, he says that they shouldn’t be seen as representative of all people with Long Covid.

To begin with, the study was limited to participants with Long Covid who actively sought treatment for their ongoing neurological symptoms at a neurology clinic. “Equally as important is that [the participants in the study] were selected because they’ve had symptoms for at least six weeks,” Kaplin explains. “And so [the researchers] were selecting people who were more likely to have a progressive and long course.”

Although there still aren’t definitive statistics on the number of Americans living with Long Covid, as of March 2022, estimates ranged from 7.7 million to 23 million people, according to a report from the Government Accountability Office. But the condition’s mysteries don’t end there. 

A separate study published today in the Annals of Internal Medicine from researchers at the National Institutes of Health (NIH) confirms what is already known — or technically, unknown — about Long Covid: That its cause has yet to be identified, and it remains unclear how or why the wide range of long-term post-Covid symptoms develop. 

And while we still don’t know how long a person’s Long Covid symptoms might last, post-Covid clinics like the ones at Northwestern and Johns Hopkins are providing people with the available tools to help them cope with the disruptions to their lives. But for the most part, those aren’t cures or long-term solutions. 

For now, the future of the millions of people who, like myself, are living with Long Covid, depends on further research — something Koralnik and his team call for in their article. “The take-home message is that people are suffering,” Kaplin says, “and Long Covid needs to be studied better in order for it to be treated and managed and understood.”