Monday was World Tuberculosis Day and, as usual, Americans had reason to celebrate, with incidence rates that are among the best anywhere, according to the World Health Organization. But that does not mean there is not room for further improvement, especially in San Diego County.
In a recent announcement calling for greater tuberculosis awareness, the San Diego County health department indicates that the region had 7.5 tuberculosis cases per 100,000 residents in 2024, a rate that is more than double the national rate of 3 per 100,000 and 5.4 per 100,000 in California.
Though the most recent country-by-country data is from 2022, it shows that the average rate across the globe is 134 cases per 100,000 residents with countries such as the Democratic Republic of the Congo, Mongolia and the Philippines listed as having some of the highest rates globally.
Though local numbers, compared to other commonly tracked infectious diseases such as the flu and coronavirus, are small, TB is nonetheless on a continued rise in San Diego County and in most locations nationwide. San Diego tallied 247 total cases in 2024 compared with 243 in 2023. While it is the fourth consecutive annual increase, local totals have not yet reached the recent high of 264 cases recorded in 2019.
As was the case for most infectious diseases, tuberculosis cases fell in 2020, reaching 193 in a year characterized by a wide-ranging stay-at-home order and other transmission-reducing practices put in place in reaction to the COVID-19 pandemic.
So, while TB numbers have continued to rise since the pandemic, they have not yet fully regained the heights reached in 2019.
While case numbers do not yet show a larger problem than existed before the pandemic, the trend is headed in the wrong direction, especially since the county has been engaged in a tuberculosis elimination campaign since January 2020.
Unlike the flu or COVID-19, tuberculosis has a long lead time. The bacteria that causes the disease can live in the human respiratory tract for many years, or even decades, before becoming active, invading the bloodstream and causing deadly illness. About 175,000 people who live in San Diego County are estimated to be carrying “latent” infections, which are in a sort of dormancy and do not spread.
The key to winning the tuberculosis fight, then, is detecting and eliminating latent infections before they become active and gain the ability to spread from person to person through tiny water droplets shed through everyday activities such as coughing, speaking or singing.
Dr. Jeffrey Percak, medical director and chief of the county’s Tuberculosis Control Program, said that the organization’s main TB clinic and associated health centers screened about 4,000 local residents for TB infection in 2024 with about 800 of those initial tests coming back positive. The number was similar, he said, in 2023, and no data was available on what percentage of those who tested positive took the antibiotics necessary to eliminate latent infections. Those numbers, though, do not include testing and treatment performed by private health care organizations.
Work is underway with a wide range of medical providers to better understand treatment rates in order to determine what percentage of those who are screened and found to have an infection make it all the way to a cure.
“We have started collecting that data so that we’re able to look at it as a proportion of people achieving all of the steps that would be needed to lead to the outcomes that we’re looking for,” Percak said.
Why is it that San Diego County has a higher-than-average per-capita level of TB activity? TB rates are known and observed to be higher in places with higher proportions of residents who travel internationally, especially to countries where the disease is much more prevalent.
“A majority are born outside the United States, and that reflects a combination of the likelihood of having been exposed previously in life but also reflects an intersection of social determinants of health like language barriers, health literacy, access to care, education and housing,” Percak said.
Chronic health conditions such as HIV, diabetes or other immune system problems increase risk as does smoking.
Those with chronic conditions who were born outside the United States are at the top of the list of people who should get tested. One common misconception, Percak said, is that the cases that pop up each year are among recent immigrants. However, that’s not true. He said that because TB can take so long to become active, cases are most often among those who have been around for some time.
“The overwhelming majority of people who are diagnosed with TB who are born outside the United States are not recently arrived,” Percak said.
“These are people who are long-standing parts of our community, who have been here for many years or decades before they become sick.”
A big part of the fight toward TB elimination is around getting those who do test positive to follow through with antibiotic treatment. In the past, such treatment took many months to complete and involved antibiotics with a significant impact on liver health. However, a new crop of medications significantly reduces those burdens, making the process easier and more comfortable to undergo.
Those without health insurance can call the county’s TB clinic at 858-573-7300 for more information.