Severe COVID can awaken ‘dormant TB,’ says doctor and tuberculosis researcher

MANILA, Philippines — In mid-May Natividad Avena, 91, was gripped by a weeklong malaise and was barely eating when she was taken to hospital and subjected to such procedures as an X-ray, swab test and blood work.

Two days later her family members were told that she had COVID-19 and pneumonia. But another diagnosis surprised them: She also had tuberculosis (TB).

Avena survived COVID-19 and is now in the fourth month of a six-month TB regimen.

Dr. Mary Ann Lansang, a medical professor, clinical epidemiologist, and one of the leading TB researchers in the country, says Avena’s case is more common than the public may think, because the risk factors for COVID-19 and TB in the elderly are similar.

Lansang cites worrying statistics: 27.5 percent of Filipinos have latent or dormant TB. And the pandemic threatens to drive the number of TB cases higher.

“It’s possible that in those who will develop moderate to severe COVID-19, the latent TB will get activated,” she says.

Bacterial infection

TB is an infectious but curable disease. The bacteria are passed by infected persons when they cough, sneeze or spit.

The Philippines has the highest TB incidence in Asia, with 554 cases for every 100,000 Filipinos, according to the Department of Health (DOH), citing the 2020 global TB report of the World Health Organization (WHO).

The WHO says a quarter of the global population has latent TB, meaning they have the infection but the bacteria are inactive and cause no symptoms.

Latent TB is not contagious. But it can turn into active TB, which is contagious, so treatment is important, Lansang says.

In 2018, the Philippines made a commitment at the United Nations High Level Meeting on TB in New York City to find and treat 2.5 million TB patients by 2022. But the pandemic has derailed TB case-finding efforts, and “we are now below 2018 levels,” Lansang says.

How common is it to be infected with both TB and COVID-19?

Says Lansang: “The global TB network is coordinating with more than 100 countries assessing TB and COVID-19 co-infections. But I suspect there are more cases than what are being reported, because of the problem of case-finding today.”

Like those at high risk of developing COVID, those with compromised immune systems or with comorbidities such as HIV and diabetes, or are smokers have a higher risk of developing active TB, says Lansang.

Advanced age is also a risk factor.

“Sometimes we forget because COVID is here. But before 2020, TB was the top-ranked most fatal infectious disease in our country,” Lansang says, adding that she worries that TB and COVID-19 will become a “syndemic,” or a set of two or more diseases interacting synergistically.

For older COVID patients, some experimental medications such as tocilizumab can be a problem.

“One of the possible effects is it could activate TB, so doctors screen for TB before administering tocilizumab. And when there are signs of latent TB, they will likely also give prophylactic treatment for TB,” Lansang says.

She says strong drugs can be a “double-edged sword” because these can be hard on other organs.

Avena’s granddaughter Patty says she and the rest of the family had no inkling that their “lola” had active TB and were even in disbelief.

“I was like, ‘Huh? Why would she have TB?’ Her house is clean. We got curious how it happened, since the impression is that you get TB from dirty surroundings. But the doctor explained the concept of latent TB,” Patty recalls.

2 diseases, 1 stone

Some labs are now able to process tests for both TB and COVID-19, Lansang says, suggesting that the best way to find cases is to test potential patients for the two diseases.

One such lab is the nonstock, nonprofit Tropical Disease Foundation (TDF), which is focused primarily on finding and treating TB patients, and now also tests for COVID-19.

“The main barrier to finding more TB cases is really the Filipinos’ health-seeking behavior,” Lansang says. “If before, only 66 percent of Filipinos consult with a doctor or community health worker when they have a persistent cough, now it is even worse, since people are afraid to leave their homes, or be branded a COVID-19 patient.”

Lansang cites a recent online survey of the US Agency for International Development (USAID) showing that TB case-finding has dropped mainly because of the fear of medical consultations during the pandemic.

“The second barrier is access,” she says. “Labs have been converted for COVID detection, and attention is diverted. The health workers that used to … find TB have been co-opted for contact tracing for COVID.”

TDF laboratory manager Anthony Geronimo says the pandemic has drastically lowered the number of patients who come to be tested for TB.

“Prepandemic, we would have about 20 walk-in paying customers a month. Now we’re down to about one or two,” Geronimo says.

Fortunately, Lansang says, the detection of one disease does not have to be at the expense of the other.

“One of the solutions is to pay attention to both. When asking about COVID-19, let us instruct our contact tracers to ask about TB as well. They can provide leaflets and give information, while asking if anyone in the household has a persistent cough,” she says.

This line of questioning is important, Lansang says, because the pandemic has led most people to equate a cough with COVID, when a cough that lasts two weeks or longer can be a sign of TB.

She says the DOH’s National TB Control Program has started encouraging labs to conduct tests for both COVID-19 and TB.

—WITH A REPORT FROM INQUIRER RESEARCH

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This story is in support of the #TBFreePH campaign of the DOH. With the help of USAID, #TBFreePH aims to increase and improve conversations about TB and help address stigma and discrimination experienced by persons with TB.