INCIDENCE OF latent tuberculosis may be higher among healthcare workers, more so in nurses than doctors, a study by Christian Medical College (CMC), Vellore, has found. The study underlines the need for regular screening of healthcare workers not just for active tuberculosis (TB), but also latent TB bacteria.
Latent TB means the bacteria is lodged inside a person’s body in a dormant stage, waiting for poor immunity and low diet to get activated. Healthcare workers tending to patients remain at five times higher risk of getting infected than normal population, the pulmonary department of CMC has found.
In India, about 35-40 per cent population is estimated to be infected by latent TB, and one in every 10 people infected by the bacteria is likely to get active tuberculosis infection.
“Currently, India’s Revised National Tuberculosis Control Programme (RNTCP) has a screening policy for only children aged up to six for latent TB,” Yogesh Patel, consultant with RNTCP, said. No screening for latent TB, however, is provided for adults and healthcare workers.
The CMC study found that latent tuberculosis was present in 52 per cent nursing students as opposed to 27 per cent MBBS students in the medical college.
In 2017-18, 278 MBBS students were screened of which 27 per cent had latent TB. Of them 42 students, who got recent exposure to bacteria, were put on preventive treatment of prophylaxis for 3-12 months. “The risk of getting TB is maximum for two years after exposure to the bacteria. We targeted those people for intervention,” Dr DJ Christopher, head of pulmonary department, CMC Vellore, said.
The risk of infection was higher among nursing students who remain in close proximity to patients for longer durations than doctors, the study found. Of 436 nursing students undergoing postgraduate, diploma and undergraduate courses who were screened at CMC between 2007 and 2011, at least 52 per cent had latent TB. The incidence of infection was higher among postgraduate (MSc) and diploma students at 72.7 and 84.2 per cent respectively.
“We found that the risk of exposure increased with postgraduate students because they are exposed for longer duration,” Christopher said.
The study also indicated the need to regularly screen healthcare workers and put them on preventive treatment. Currently, tuberculin skin test and Interferon-Gamma Release Assays test are the most methods of diagnosing latent TB.
In Mumbai, the TB control office will soon launch a pilot project to test people in close contacts of TB patients for latent TB bacteria.
Helene-Mari Van Der Westhuizen, working in South Africa to control TB epidemic, said they have already begun preventive therapy for health workers. “They are at the first point of risk. If we have to control the infection, we must protect their health.”
In Group of TB Hospital in Mumbai, India’s largest TB hospital, tests are only conducted among staff to screen active TB, not the latent bacteria. “Preventive drug therapy is also associated with toxicity. Instead we look at other preventive measures,” superintendent Dr Lalitkumar Anande said, adding that staffers were given banana, milk and protein-laden food.