A California hospital continues a high-stakes tuberculosis follow-up of more than 350 newborns exposed to an infected healthcare worker. With testing reliability questionable in such infants, the babies are essentially being treated empirically with isoniazid (INH) for a TB strain that is susceptible to the first line drug. Hundreds of mothers and hospital employees are also being tested.
“No one has tested positive for TB from this possible exposure,” says Joy Alexiou, public information officer for Santa Clara Valley Medical Center in San Jose, CA. “The vast majority of infants have been in or have been scheduled for their screenings and to receive the antibiotic treatment.”
Concerns have included that even if the babies are treated successfully now, there could be a risk that TB could remain latent in their systems, returning later in life if they become immunocompromised.
“That is highly unlikely because they are being treated before a latent infection takes place,” Alexiou says. “When it comes to a person with latent TB, INH greatly reduces the risk they will ever become active.”
The hospital notified patients by phone and letter on Dec. 11 that some 350 infants and their mothers may have been exposed to a healthcare worker with active tuberculosis between mid-August 2015 and mid-November 2015. Now on leave for treatment, the employee worked in the newborn nursery in the hospital’s Mother & Infant Care Center.
LOW RISK, SEVERE OUTCOMES
“While the risk of infection is low, the consequences of a tuberculosis infection in infants can be severe,” Stephen Harris, MD, Chair of Pediatrics at Santa Clara Valley said in a statement. “That’s why we decided to do widespread testing and start preventive treatments for these infants as soon as possible.”
The hospital is doing both diagnostic testing and preventive daily treatments of isoniazid on the infants, which are being monitored closely for any signs of active infection with Mycobacterium tuberculosis. Elements of risk include that the newborn immune system is not fully developed and may not respond to testing. Thus, X-rays and preventive treatment will be done, and of course clinicians will act quickly if there is any sign of reduced susceptibility of the TB strain to the first line drug administered.
Parents of newborns, often hypervigilant in any scenario involving their baby, expressed enough concern to elicit a second hospital notice to patients on Dec. 15, stating, “We understand that people are concerned about this unusual situation and we apologize for the anxiety it may have caused.”
In addition to the babies, 368 mothers and 338 hospital employees were also potentially exposed to the infected worker. All patients, visitors, and employees who were potentially exposed to the infected worker have been identified. The employee underwent her annual tuberculosis test in September 2015. The screening was negative and the employee did not show symptoms at any time. Her personal physician discovered her TB when she underwent evaluation for an unrelated medical condition.
However, the hospital reports the nurse was asymptomatic at work and showed no classic signs of active TB infection such as cough.
“The employee had no symptoms of TB and the risk for infection from this possible exposure remains low,” Alexiou says.
HIGH TB RATE
Santa Clara County has one of the highest TB rates in California. There were 163 cases of active TB in Santa Clara County in 2014, a 10% decline from 181 cases the year prior. The TB case rate is 8.8 per 100,000 residents, ranking Santa Clara County fourth among all jurisdictions in California. The case rate is 1.5 times higher than the overall state rate (5.6) and almost three times the national rate (3.0). While recent immigrants accounted for almost one-third of TB cases among foreign-born individuals, the majority (70%) of TB cases among foreign-born individuals occurred among those living in the U.S. for more than five years, the state health department reported.
Nationally in 2014, a total of 9,412 new TB cases were reported in the United States, with an incidence rate of 3.0 cases per 100,000 persons — a decrease of 2.2% from 2013. Although overall numbers of TB cases and rates continue to decline, the percentage decrease in rate is the smallest decrease in over a decade, the CDC reported. The rate among foreign-born persons in the United States in 2014 was 13.4 times higher than among U.S.-born persons. Racial/ethnic minorities continue to be disproportionately affected by TB within the United States. Asians continue to be the racial/ethnic group with the largest number of TB cases. Compared with non-Hispanic whites, the TB rate among Asians was 28.5 times higher, whereas rates among non-Hispanic blacks and Hispanics were each eight times higher. Four states (California, Texas, New York, and Florida), representing approximately one-third of the U.S. population, accounted for half of all TB cases reported in 2014, the CDC reported.