India’s number of tuberculosis patients registered weekly dropped by a precipitous 75 per cent during the first three weeks of the nationwide Covid-19 lockdown and could lead to excess TB deaths, health researchers have cautioned.

The country’s average weekly count of reported cases over the three weeks after March 22 was 11,367 compared to the average weekly count of 45,875 in the previous weeks of 2020, a senior epidemiologist with the World Health Organization (WHO) said.

The drop may have resulted from delays in entering data in the country’s real-time national online TB surveillance system, reduced attendance at health centres, reallocation of health staff or a reduction in TB testing and detection, Philippe Glaziou, team leader for TB epidemiology, said in a research paper.

The paper has noted similar falls in TB case detections in China and Indonesia and cautioned that if TB case detection and treatment services are not maintained at the level before the Covid-19 pandemic, mortality from TB could rise among vulnerable populations.

“The large number of excess deaths due to unusual delays in case detection highlight the need to urgently restore TB detection and care services and keep them prioritised as essential health services,” Glaziou told The Telegraph over email.

If global TB case detection decreases by an average 25 per cent over a period of three months compared to before the pandemic, Glaziou has estimated, there could be an additional 190,000 deaths raising the total global TB deaths in 2020 to 1.66 million.

This would be close to the global TB deaths in 2015 and a “serious setback” to efforts to lower TB deaths.

Indian health ministry officials have said they have instructed states and healthcare services to ensure that all critical medical services, including TB detection and treatment, be given a priority even as they fight the Covid-19 pandemic.

But doctors tracking India’s TB control programme and patients’ rights groups have observed that patients are facing hurdles in efforts to seek diagnosis and delays in access to anti-TB medications.

“As it is, the vast majority of TB patients get diagnosed several weeks after onset of symptoms,” said Anurag Bhargava, professor of medicine at the Yenepoya Medical College, Mangalore. “If they face further delays during such disruptions, the disease could get worse.”

In rural areas, Bhargava said, TB diagnosis is available at the level of community health centres. The restrictions and absence of public transport under the lockdown could have prevented some patients from seeking diagnosis.

“A majority of our TB patients are also undernourished and the lockdown could have aggravated this poor nutrition,” Bhargava said. “Poor nutrition coupled with delayed diagnosis could cause the disease to progress to severe condition and accelerate death.”

India has set a target of reducing TB deaths by 90 per cent from around 480,000 in 2015 to 48,000 by 2025, or from 1,315 deaths per day to 131 deaths per day. Bhargava had earlier this year published a paper urging comprehensive TB care that would address issues such as severe under-nutrition.

India currently accounts for around 440,000, or 30 per cent of global TB deaths. “The share of excess deaths (under delayed case detection scenarios) will likely be different from the 30 per cent of the global excess, though probably not very different,” Glaziou said.

His paper has also pointed to a 20 per cent drop in TB case detection in China during February 2020 compared to February 2019 and a 68 per cent drop in Indonesia between January and March this year. Brazil, in contrast, has not shown any fall in weekly TB detection.

The Covid-19 pandemic has challenged healthcare resources worldwide but Glaziou said Covid-19 and TB case detection programmes could seek synergies.

“This issue is not easily addressed in resource-constrained countries,” he said. “Not all health services are essential in a time of crisis. But TB remains the first cause of death from a single infectious agent and it is essential to maintain detection and care.”

He said synergies could be sought between Covid-19 and TB programmes as both require testing patients with respiratory symptoms and both require tracing contacts to cut the chain of transmission.