Omicron 3 appears to cause more cases of brain inflammation and fits twice as many patients than other strains, and scientists say the Centers for Disease Control and Prevention needs to issue a “warning that the disease may be turning out to be more complicated and more difficult to treat than previously thought.”
The report, published Thursday in JAMA Network Open, drew largely on data from the Tarrant Regional Medical Center’s Global Virus Network, which screens patients with confirmed cases of brain inflammation for a virus known as Methicillin-resistant Staphylococcus aureus, or MRSA. It analyzed more than 2,000 cases of clinical infection with Omicron 3.
With the exception of one complication, nearly all of the patients with brain inflammation who received medical treatment at the hospital developed a form of MRSA in the same location, according to data from the hospital.
“It could be these patients have experienced an infection before and their system has been primed or primed them to develop a form of MRSA. Some of them could be extremely ill, and some of them may be producing antibodies that have inhibited the process of damaging the brain cells,” said Dr. Ajay Kekkar, who led the study, of the Tarrant Regional Medical Center.
Using data from the Army Materiel Command Network for Biological, Chemical and Radiological Defence and the Food and Drug Administration, the study found that in cases of CNS inflammation, rate of cumulative MRSA mutations increased the more time elapsed before intervention.
That correlates with at least one other previous study from the same research team, which revealed higher rates of MRSA in patients with CNS inflammation than those who had not. Omicron 3 was the strain related to this previous study, Kekkar said.
“When we thought that they were just generalized symptoms of inflammation, it was clear that was not the case,” Kekkar said. “This is a very rare disease. There have been only about 100 infections from this Omicron variant diagnosed worldwide. And in our data, there were 88 cases. That’s about one case for every 28 patients.”
Still, Kekkar said there is a tendency to underestimate the complications of MRSA in the case of brain inflammation. He said that infected patients are more likely to have multiple complex follow-up care from hospital personnel and that it was rare for those codes to be clinically indicated. He believes that diagnoses of brain inflammation could be biased because those resources, as well as patients, are typically stretched thin.
Kekkar cited the CDC report from 2017, which warned of a “dramatic increase” in cases of brain inflammation, as evidence of increasing severity and length of the illness. In that report, a new strain of MRSA in particular was ascribed to Omicron 3. However, Kekkar said that the CDC was taken by surprise by the breadth of the outbreak, noting the report added about 30 cases to the registry.
“This new strain isn’t just affecting people in the U.S.,” Kekkar said. “It’s been seen in Asia and Europe as well. They don’t have formal guidelines in place for how to identify the MRSA strain.”