Tuberculosis, a virus often associated with the death of Victorian-era monarchs, was recently contracted by more than 200 high school students in San Francisco. The outbreak was a reminder of the Bay Area’s history.
Alameda, Santa Clara, San Francisco and San Mateo counties each rank among the top 10 in the state when it comes to cases of tuberculosis, or TB, with rates three times higher than the national average.
“We have a lot of people who have diseases (hidden tuberculosis), and they should be tested and treated. But they are not, for various reasons,” said Dr. Amit Chitnis, tuberculosis administrator for the Alameda County Department of Public Health.
Although the incidence of tuberculosis is still rare compared to developing countries, it has taken the title as the most deadly infectious disease from COVID-19 in 2023, according to the World Health Organization.
The Bay Area has long been the epicenter of the disease on the West Coast because of its ports and as a checkpoint for immigrants from places like Asia and Latin America.
For about 50 years until the 1940s, immigrants were heavily scrutinized on Angel Island, a 740-acre area in San Francisco Bay accessible only by boat or private boat.
If immigrants were diagnosed with tuberculosis, they were sent to an island quarantine station to be treated with strict isolation, fresh air and long rest until doctors cleared them, according to the CDC.
Currently, the US Citizen and Immigration Services tests immigrants for existing diseases, but those with a silent problem, known as latent TB, go undiagnosed.
More than 90% of active cases in the Bay Area now occur among immigrants from countries with less access to vaccines, according to Stanford tuberculosis researcher Jason Andrews. The rate is highest for people born in the Philippines and Vietnam, followed by India, China and Mexico.
“TB thrives where there’s inequality. It thrives in underserved communities, in places where we’re malnourished,” said Andrews. “It helps to look at TB as a common disease with inequities and poor social support systems.”
In Alameda County, cases were concentrated in Oakland’s Chinatown and other high rates were found in South San Leandro, West Hayward, Union City and South Fremont, according to a 2024 Alameda County Department of Public Health report.
The San Mateo Department of Public Health found that 45% of the cases occurred in Daly City. Rates in Santa Clara County were highest in San Jose — which had the second-highest rate of any metropolitan area in the continental US in 2021, according to Santa Clara County Public Health.
In about two-thirds of active cases, the person has lived in the US for more than 10 years, according to Bay Area public health agencies. Those at greatest risk of developing acute TB become an existing infection are those who have been exposed to someone with active TB, people with weakened immune systems due to diseases such as HIV and diabetes, and young children under five years of age.
Tuberculosis does not choose who it infects. In 1929, Col. PS Rawls, chief medical officer at the Arroyo del Valle Sanitarium south of Livermore, contracted the disease “either (from) his experiences in the World War or from close contact with patients,” the Oakland Tribune wrote at the time.
As for why the late January outbreak occurred among children at a private high school in San Francisco, testing for latent TB is not available.
This detection gap is a major predictor of this disease in the US and is of concern to public health professionals. Identifying and treating active TB has been recommended as an important strategy to prevent outbreaks among immigrant and indigenous communities for more than a generation by public health experts, according to a 2002 Cornell University study.
“Although most of the burden of tuberculosis in the world is in the developing world, globalization has brought it to our doorstep, and reminds us that we live in an increasingly connected world,” said lead author Dr. Kamran Khan.
But being tested for active TB – with treatment that can take up to nine months to completely eradicate the bacteria – is an expensive endeavor with low returns, considering that only 5% of people with active TB will develop active disease.
Chitnis said public health agencies are focusing on cases and contacts during outbreaks of violence “because they are the most vulnerable.”
In recent years, the U.S. has lost a disease it has already conquered because of major cuts in facilities charged with fighting the disease and protecting vulnerable populations, Andrews said. These cuts contribute to deep poverty, overcrowded living conditions and poor sanitation that create the perfect environment for the world’s deadliest disease, says a Stanford researcher.
“TB is like a barometer of our public health system … It is a visible and tangible problem that we must be able to control and eliminate in the United States,” Andrews said. “The fact that we are losing ground on this is a sign of the sickness of our health and government institutions, but also of the social networks we have for people who are at high risk.”
