New Delhi: Effects of preventive treatment for tuberculosis could start to wane after just one year of completing the antibiotics course in high-burden settings, while the protection lasts for at least eight and 13 years in medium and low-burden countries, a study has found.
Findings published in The Lancet Respiratory Medicine show that tuberculosis preventive treatment (TPT) offered a strong protection during the first 12-24 months across settings with all levels of TB burden.
Consisting of antibiotic medicines that can prevent inactive TB infections from developing into active disease, TPT is considered an important public health tool for protecting individuals and countries from the deadly infectious disease.
Preventive treatment can include medications, such as isoniazid and rifapentine — typically prescribed for four months — and is critical for the World Health Organization’s goal to end the global TB epidemic by 2035.
TPT has been shown to be highly effective, but how long this protection lasts — and whether its duration varies by region or community risk level — remains unclear, researchers at the US’ Boston University and the University of California, Berkeley, said.
They estimated TB risk among people with TB infections in 24 countries and found that TPT offered strong initial protection, but long-term protection varied depending on the burden of TB disease in each area.
“Of 4,66,523 participants from 47 studies, we included 84,128 individuals from 44 cohort studies across 24 countries. TPT was highly protective within the first year but declined over the course of follow-up in all settings, with greater effects observed in low-burden and medium-burden settings,” the authors wrote.
The results showed that high-burden countries should consider combining TPT with other interventions to achieve the long-term benefits these medications are capable of providing, they said.
Lead author Lauren Linde, an epidemiology doctoral student at Boston University’s school of public health, said, “In this study, our results corroborated something that was already well-established — TPT is highly effective at preventing TB progression among close contacts and people who have been infected with TB.”
“However, our finding that the initial effect of TPT declined so rapidly in very high-burden settings strengthens the case for not placing too much emphasis on TPT in isolation from other interventions that address ongoing community transmission,” Linde said.
