The 1985 HIV/AIDS epidemic commenced just as tuberculosis (TB) prevention and control measures had been lifted in the US.
- Thus, a surge of patients arose with both latent TB (infected patients who test positive but are not sick) and active TB (infected patients who test positive and are clinically symptomatic) in vulnerable groups, including prison populations, the homeless, and IV drug abusers.
- Added to these susceptible populations were immigrants arriving from continents and areas where TB is endemic, such as Africa, Asia, and Latin America.
Many patients were lost to follow-up or did not complete their designated drug therapy when there was a marked improvement in their health. Because of the long treatment period (12 -18 months) combined with drug intolerance, patients often discontinue treatment that is not monitored. Discontinuing therapy early allows selective resistance to occur with subsequently increased transmission of resistant strains.
To prevent transmission, a structured anti-tuberculosis regimen is mandated. Non-compliance with the prescribed regimen led to the epidemic of the superbug, a multidrug-resistant TB (MDR-TB), resistant to the most effective first-line drugs isoniazid (INH) and rifampin (RIF). Although second-line drugs were available, their action is slow, and serious side effects are common. In the 1990s, the peak of non-compliance in the U.S. culminated in a New York City epidemic resulting in a severe outbreak of MDR-TB in 350 patients who were suffering from HIV/AIDS as well.
The maps to the right show the percentage of new TB cases with MDR-TB (upper) and previously treated TB cases with MDR-TB (lower) in 2018. Note that globally in 2019, an estimated 3.3% (95% confidence interval [CI]: 2.3–4.3%) of new cases and 18% (95% CI:9.7–27%) of previously treated cases had MDR/RR-TB. (WHO, 2021)
