Early in the Covid-19 pandemic, new diagnoses of tuberculosis dropped like a stone in the United States. Data released Thursday by the Centers for Disease Control and Prevention suggest the pandemic effect has pretty much worn off; TB is nearly back to pre-2020 levels.
“We’re getting … close to where we were pre-pandemic; not quite back yet with increases in cases in the last two years,” Philip LoBue, director of the CDC’s division of tuberculosis elimination, told STAT in an interview. “Everything looks like we’re going to end up maybe next year or the year after basically back to the situation we were in pre-pandemic.”
LoBue was speaking about the release of the 2022 interim estimates of new tuberculosis cases in the U.S., which estimate that 8,300 TB cases were reported last year, at a rate of 2.5 cases per every 100,000 Americans. In the first year of the pandemic, the rate of TB cases fell to 2.2 per 100,000, rising to 2.4 per 100,000 in 2021.
The 2022 TB estimates were published in the CDC’s online journal, Morbidity and Mortality Weekly Report. Their publication coincided with World Tuberculosis Day, which is Friday.
The 2022 increase was due to more cases among people newly arrived in the United States as well as a higher incidence of cases among American Indians, Alaska Natives, Native Hawaiians, and other Pacific Islanders, the report stated.
There was a slightly lower incidence among people aged 65 and older — potentially because so many people in this age group have died from Covid, LoBue said.
There were increases among persons aged 15–24 years, and in children aged 4 and younger, a worrisome sign, he said. “We always are concerned about infections in young children because it means that we have transmission occurring in the U.S. and that’s something we want to interrupt as quickly as possible to prevent additional cases.”
In adults, a diagnosis of tuberculosis may signify a recent infection. But more often it signals that an infection that occurred months, years, even decades ago that had been in a latent form became active. Reactivation, as it’s called, occurs in about 5% to 10% of people who carry latent TB.
With young children, this is much less likely to be the case. “When we see infections in children, it’s not that they could have been infected 10 years ago when they lived in a different country. It means that that transmission likely occurred recently and the transmission occurred in the U.S. So that’s why it’s a concern,” LoBue said.
Children often experience worse disease with TB than adults do. “They get bad forms of TB like meningitis and disseminated TB. And so those are forms of TB that can have worse outcomes, including potentially death or long-term factors like affecting your neurologic development,” LoBue said.
The reason for the decline in reported cases during the early stages of the pandemic is not perfectly clear. But it’s thought that a pattern that has been reported with other health care issues — that people shied away from seeking medical care for fear of catching Covid — was at least partially responsible. The sharp reduction in international travel and migration at the time also likely contributed to the decline. TB rates are considerably higher in some other parts of the world than they are in the U.S.
Additionally, some TB cases were confused with Covid, slowing diagnoses.
“We have some anecdotes where we know from some of the health departments where there were people who clearly had their diagnosis delayed because, you know, they went in, it was respiratory illness. Everyone thought it was Covid. They were tested. All the tests were negative. They went through the cycle several times before someone said, oh, maybe this isn’t Covid, maybe it’s TB,” LoBue said.
That underscores a problem faced by those fighting to rid the country and the world of tuberculosis. Though humans have suffered from this disease for centuries, it is not top of mind, even among health care providers, in the modern era.
“The fact is that TB is still here. We still have TB in the U.S., but not many people really have much awareness about it,” Lobue said.