US tuberculosis cases were at the highest level in a decade in 2023
US tuberculosis cases were at their highest level in a decade in 2023, according to a new report.
While cases decreased at the beginning of the COVID-19 pandemic, they have been rising since.
Tuberculosis (TB) rates were up among all age groups, with more than 9,600 cases reported, a 16 per cent increase from 2022 and the highest since 2013, according to a report from the Centers for Disease Control and Prevention (CDC).
Most US TB cases are diagnosed in people born in other countries, but there were increases among people born in the US as well. The high number of cases is partly due to a global surge as well as increases in migration and post-pandemic travel.
Other factors are also at play, including other illnesses that weaken the immune system and allow latent TB infections to emerge.
The World Health Organisation (WHO) said TB was behind only COVID-19 in infectious fatal diseases worldwide in 2022.
'A little more than expected'
CDC officials expected TB numbers would rise, but the 2023 count “was a little more than was expected,” said Dr Philip LoBue, director of the CDC's Division of Tuberculosis Elimination.
Despite the jump, the number and rate of new TB cases each year remain smaller than it was in the past, and the US has a lower rate of new TB cases than most countries.
Tuberculosis is caused by bacteria that usually attack the lungs, and is spread through the air when an infectious person coughs or sneezes. If not treated properly, it can be fatal.
In the late 1800s, TB killed one out of every seven people living in the United States and Europe. But the development of antibiotics and public health efforts succeeded in treating infections and tracking down those they infected, leading to cases falling for decades.
In Europe, TB cases rose in 2022 compared to the previous year with 38 out of the 53 states in WHO's European region, which includes parts of Central Asia, reporting increases.
More than 36,000 cases were reported in the EU/EEA up from 33,500 in 2021, according to WHO.
Latent TB
The new CDC statistics are not a count of how many people were newly infected in 2023, but rather of how many people developed a cough or other symptoms and were diagnosed.
An estimated 85 per cent of the people counted in 2023 were infected at least a year or two earlier and had what’s called latent TB, when the bacteria enters the body and hibernates in the lungs or other parts of the body. Experts estimate as many as 13 million Americans have latent TB and are not contagious.
When the immune system is weakened — by certain medications or other illnesses like diabetes and HIV — the TB wakes up, so to speak.
Nicole Skaggs said she was infected in 2020, but didn’t develop symptoms until 2022 — after she got sick from COVID-19.
“Anything that can take out or lower your immune system can put you at risk,” said Skaggs, 41, a property manager in Bothell, Washington.
CDC officials called the idea that COVID-19 has played a role in increased reactivation of TB “an important question".
Scientists are still learning what causes latent TB to reactivate and "I would consider it an unknown at this point,” LoBue said.
“It’s too early to tell” what will happen to TB trends in the next few years, he also said.
TB vaccines are being developed, and some public health workers who were focused on COVID-19 are now back to trying new approaches to preventing TB.
On the other hand, one of the key antibiotics used against TB has been in short supply in recent years. Plus, drug-resistant TB infections have popped up in a fraction of cases.
