“The same thing is true for Covid-19,” Fallon added. “If you only report cases of people who have been tested, and the tests are not widely available, then you’re going to have a low rate.”
To Crystal, the one bright spot in the coronavirus testing debacle is that it has helped to educate the wider public on issues relating to diagnostic testing — something those in the trenches of Lyme disease when it first began to emerge decades ago had already learned.
While encouraged by the speed with which trials and vaccine development have gotten underway, Fallon noted that there’s still a long way to go. “I think we as medical students who go into medicine thinking that science is so advanced and it knows so much,” he said. “But over the last 30 years, I’ve learned that, yes, science has learned a lot, but it still needs to learn a vast amount more.”
DIAGNOSING LYME DISEASE has always been challenging. Similar to Covid-19, Lyme disease can cause a range of symptoms, such as rash, fatigue, joint pain, facial paralysis, heart problems, dizziness, and more.“These symptoms are subjective and nonspecific,” said Timothy Sellati, chief scientific officer at the Global Lyme Alliance, a nonprofit Lyme disease research group for whom Crystal writes a weekly column, “and so it makes it very, very challenging for a physician to do a differential diagnosis and make certain that this individual has Lyme disease and not chronic fatigue syndrome, not multiple sclerosis, not ALS, and not influenza.”
The enzyme-linked immunosorbent assay (ELISA) detects antibodies produced against specific pieces of protein from Borrelia, known as antigens. ELISA tests are fairly sensitive, which means that people who actually have Lyme disease are likely to test positive. The problem is that these tests aren’t very specific and give a high number of false positives (that is, not everyone who has a positive ELISA actually has Lyme). The other major type of antibody test in the early 1990s was the Western blot, which detects antibodies against a set of different Borrelia proteins. The Western blot is specific, such that people without Lyme reliably test negative, but not very sensitive. By the time of the 1994 Dearborn meeting, manufacturers had developed a range of different indirect tests for Lyme, none of which produced the kind of definitive results needed to help diagnose a disease that could mimic a huge number of other conditions. What resulted from the meeting was the two-tiered testing protocol, in which a positive or equivocal ELISA would be followed by a Western blot for confirmation. Subsequent studies, however, showed that even this two-tiered approach didn’t always adequately catch all cases of Lyme disease, although newer approaches are trying to change this.“ Diagnostic tests are never perfect. And now folks who are journalists and people in the public are at this time becoming educated as to the challenges and limitations of technology,” said David Ecker, vice president of strategic innovation at Ionis Pharmaceuticals, who has also worked on molecular tests for other pharmaceutical companies. “They are not perfect. They never will be.” After the Dearborn criteria were announced in August 1995, the Lyme community began to point out their weaknesses. One difficulty was the fact that the tests relied on antibodies. Antibiotic treatment in the early stages of disease was the shortest and offered the greatest chances of cure, but the body doesn’t produce antibodies to the Lyme bacterium immediately after infection. It is, Sellati says, a major issue with testing for antibodies to any pathogen, not just Lyme. Read the entire article on Undark.org