{"id":174569,"date":"2026-02-12T05:09:35","date_gmt":"2026-02-12T05:09:35","guid":{"rendered":"https:\/\/www.newsbeep.com\/us-ca\/174569\/"},"modified":"2026-02-12T05:09:35","modified_gmt":"2026-02-12T05:09:35","slug":"active-v-latent-tb-what-to-know-about-the-san-francisco-outbreak","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/us-ca\/174569\/","title":{"rendered":"Active v. Latent TB: What to Know About the San Francisco Outbreak"},"content":{"rendered":"<p class=\"drop-cap\">A little-known form of \u201csleeping\u201d tuberculosis (TB) that affects millions of Americans is making headlines after a local outbreak at a San Francisco school. The spate of cases is a reminder that sleeping doesn\u2019t mean safe.<\/p>\n<p>The San Francisco Department of Public Health declared a TB outbreak at San Francisco\u2019s Archbishop Riordan High School in late January, sparking concern from parents and city residents. The announcement came after the department diagnosed and began treating three people from the school with active TB disease.<\/p>\n<p>In the wake of the announcement, the city also identified more than 50 people with latent TB infection \u2014 an overlooked form of TB.<\/p>\n<p><a href=\"https:\/\/profiles.ucsf.edu\/priya.shete\" rel=\"nofollow noopener\" target=\"_blank\">Priya Shete<\/a>, MD, MPH, associate professor of medicine and epidemiology at UC San Francisco and co-director of the <a href=\"https:\/\/tb.ucsf.edu\/\" rel=\"nofollow noopener\" target=\"_blank\">UCSF Center for Tuberculosis<\/a>, explains what latent TB is, the health risks, and what residents should know.<\/p>\n<p>Remove this text and use the embed button to add an image.<\/p>\n<p>Featured expert<\/p>\n<p>Priya Shete, MD, MPH<br \/>UCSF associate professor of medicine and epidemiology<\/p>\n<p>What is active TB?<\/p>\n<p>Globally, TB is the world\u2019s leading infectious disease killer and is responsible for about 1.2 million deaths annually. Active TB is an infectious disease caused by bacteria that spreads through airborne droplets released when people with active TB in their lungs cough, sneeze, or speak.<\/p>\n<p>When people have active TB, they can develop symptoms, including:<\/p>\n<p>Cough lasting three weeks or moreUnexplained weight lossA loss of appetiteNight sweatsFevers<\/p>\n<p>Active TB can cause pneumonia, respiratory distress and can be fatal if untreated. Active TB can be spread. Fortunately, it can also be diagnosed and treated, and most importantly, prevented.<\/p>\n<p>What is latent TB?<\/p>\n<p>Latent TB is when a person has been infected with the tuberculosis bacteria, but the bacteria are dormant, or \u201casleep,\u201d because the immune system has figured out how to keep it in check.<\/p>\n<p>Can latent TB be transmitted?<\/p>\n<p>No. People with latent TB generally feel fine \u2014 nothing shows up on a chest x-ray, for example, and they don\u2019t have symptoms like a cough, which also means they can\u2019t spread the germ to others.<\/p>\n<p>Why worry about latent TB?<\/p>\n<p>Latent TB can \u201cwake up,\u201d and cause active TB disease. Up to 13 million Americans are estimated to have latent TB, although only around 10,000 develop TB disease each year. Still, without treatment, it can be deadly; in San Francisco, 1 in 10 people who have active TB die of the disease.<\/p>\n<p>Which tests can detect latent TB?<\/p>\n<p>There are two types of tests for latent TB. There\u2019s a skin-prick test in which a health care provider will lightly prick the skin with a harmless testing solution. Forty-eight or 72 hours later, you\u2019ll go back and have the site checked for a reaction. Generally, it\u2019s a pretty good way of testing for latent TB, but it\u2019s not perfect, and how to interpret the result depends on other health conditions.<\/p>\n<p>There\u2019s also a blood test, which we generally recommend because it\u2019s more accurate in detecting latent TB than the skin test.<\/p>\n<p>How is latent TB treated?<\/p>\n<p>Once health care providers exclude active TB disease, people with latent TB are eligible for TB preventative therapy, which can range from three months of once-weekly treatment to four months of daily pills.<\/p>\n<p>In most cases, once you finish with that, the risk of developing active TB is negligible.<\/p>\n<p>We highly recommend \u2014 especially in cases where there has been a recent outbreak or recent transmission \u2014 to go ahead and take that therapy if you do have latent TB, because you want to get ahead of it as fast as possible to prevent active TB.<\/p>\n<p>Treating latent TB keeps people healthy and reduces transmission, but your research has found major gaps in testing and treatment in the U.S. Why?<\/p>\n<p>There are a few reasons. For one, it\u2019s always challenging to get otherwise healthy people to test and take medication for something that\u2019s not bothering them. This is especially hard when it\u2019s for a disease like TB that is not generally as big a problem in the U.S. as in other parts of the world.<\/p>\n<p>It can also be hard for primary care providers to address during visits where there are competing concerns to address, such as diabetes and hypertension.<\/p>\n<p>Finally, we\u2019ve found that our health systems are not set up to easily help providers identify who may be at risk for TB by screening them, and there are no quality measures in place yet to make sure that we do.<\/p>\n<p>How has your research contributed to new regulations to keep Californians healthy?<\/p>\n<p>Our research has shown that one of the biggest gaps in preventing TB in the U.S. is getting people who are at risk screened and tested. Without this early step in care, we can\u2019t get people who need it on preventative treatment.<\/p>\n<p>I\u2019m really proud that, knowing all this, California passed Assembly Bill 2132 last year that mandates that primary care providers offer screening and testing for latent TB infection to anyone at risk for TB. This law has the potential for really making latent TB screening and testing a part of standard primary care practice for everyone.<\/p>\n<p>The challenge is that there\u2019s no \u201cteeth\u201d: clinicians who are unable to do this aren\u2019t penalized, especially if a patient\u2019s health insurance doesn\u2019t cover it.<\/p>\n<p>Does insurance cover latent TB treatment?<\/p>\n<p>In California, Medi-Cal, Medicare, and other health insurance usually covers testing for latent TB infection for people who are considered at higher risk. That includes people with weaker immune systems, those born in countries where TB is common, or people who work or live in high-risk settings. Our center helped draft a formal request to the Centers for Medicare &amp; Medicaid to expand this nationwide.<\/p>\n<p>How else is UCSF\u2019s research helping fight TB at home and abroad?<\/p>\n<p>I can\u2019t think of an area of TB research and innovation where UCSF isn\u2019t involved \u2014 from our work improving California\u2019s TB prevention systems to designing better rapid tests that enable people to start treatment as early as possible to creating <a href=\"https:\/\/www.ucsf.edu\/news\/2025\/03\/429556\/fight-against-tb-was-frozen-time-until-now-see-its-future\" data-entity-type=\"node\" data-entity-uuid=\"fbd6bd09-1ad2-4a1f-ba61-db8997785038\" data-entity-substitution=\"canonical\" title=\"The Fight Against TB Was Frozen in Time, Until Now. See Its Future\" rel=\"nofollow noopener\" target=\"_blank\">shorter TB treatment regimens<\/a>. We\u2019re also among the first to investigate TB\u2019s long-lasting impacts on a person\u2019s health even after they are cured. And we\u2019re coming into an era in which we hope an effective, long-lasting TB vaccine could be closer than ever.<\/p>\n<p>Funding for this science has been crucial in supporting the fight against TB. National Institutes of Health funding has, for instance, allowed UCSF and UC Berkeley to jointly become a national center of excellence as part of the <a href=\"https:\/\/tb.ucsf.edu\/uc-trac\" rel=\"nofollow noopener\" target=\"_blank\">UC TB Research Advancement Center<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"A little-known form of \u201csleeping\u201d tuberculosis (TB) that affects millions of Americans is making headlines after a local&hellip;\n","protected":false},"author":2,"featured_media":174570,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[30],"tags":[101,103,102,104,106,105],"class_list":{"0":"post-174569","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-san-francisco","8":"tag-san-francisco","9":"tag-san-francisco-headlines","10":"tag-san-francisco-news","11":"tag-sf","12":"tag-sf-headlines","13":"tag-sf-news"},"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/posts\/174569","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/comments?post=174569"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/posts\/174569\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/media\/174570"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/media?parent=174569"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/categories?post=174569"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/tags?post=174569"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}