World Tuberculosis Day 2026: Pulmonologist says one TB patient can infect about 15 others

TB spreads through the air in tiny droplets when a person with lung TB coughs, sneezes, talks, or even laughs. In small, poorly ventilated rooms, these germs can remain in the air for a long time and easily infect others who breathe them in.

How many of us take a cough seriously? Not many. But persistent cough can signal a deeper issue than just allergy.

A cough lasting more than 2–3 weeks, fever (often in the evening), night sweats, weight loss, and tiredness are all signs of active TB.

Some people may also have loss of appetite or cough with blood-streaked sputum.

Tuberculosis was, once again, placed as the leading infectious disease killer in 2023, surpassing Covid-19, as per World Health Organisation (WHO).

What is even worrisome is the fact that TB is extremely contagious and one person can end up infecting several others.

"One person with untreated, active TB in the lungs can infect around 10–15 other people in a year, especially close contacts like family members. This happens when the patient is not on treatment and keeps coughing and spreading germs in closed, crowded spaces," said Dr Arup Halder, Consultant Pulmonologist, CK Birla Hospitals, CMRI.

What makes TB so contagious, you ask?

TB, Dr Halder explained, spreads through the air in tiny droplets when a person with lung TB coughs, sneezes, talks, or even laughs. In small, poorly ventilated rooms, these germs can remain in the air for a long time and easily infect others who breathe them in.

But this does not mean that a person suffering from TB has to go in complete isolation or should be discriminated against.

"TB does not spread by sharing utensils, food, or touching, so families do not need to isolate the patient completely or avoid normal contact and affection," Dr Halder said.

The real risk, he said, comes from breathing the same air in small and closed rooms for long periods.

"So simple measures like keeping windows open, allowing sunlight in, avoiding crowding in one room, and letting the patient sleep near a window or in a more ventilated area are helpful. In small homes, focusing on fresh air, cough hygiene, and regular treatment is usually more practical and effective than strict quarantine," Dr Halder added.

The positive is that TB is usually curable.

"With a combination of 4 medicines taken regularly for at least 6 months or longer, TB can be cured. The key is to start treatment early, take the tablets every day as advised, and stay in touch with the TB health worker or doctor for regular check-ups," Dr Halder explained.

Then there's drug-resistant TB and which is when the real problem begins. Drug-resistant TB happens when TB bacteria stop responding to one or more of the main TB medicines.

"It happens often because treatment was taken irregularly, stopped early, or the medicines were of poor quality. Anyone can get drug-resistant TB, but the risk is higher if you live with or care for a person with DR-TB, or if you have had TB treatment in the past," Dr Halder explained.

In India, a small but significant proportion of all TB patients have DR‑TB, which is why, Dr Halder said, correct treatment of ordinary TB is so important.

What is even worrisome is that drug-resistant TB carries a higher risk of death, especially if diagnosis and treatment are delayed.

"In India, with newer all-oral treatment under the national programme, most DR‑TB patients can be successfully treated, but roughly 20–30 out of 100 may still have poor outcomes such as death, treatment failure, or being lost to follow‑up," Dr Halder added.

TB can cause infertility

TB not only affects a person's lifestyle, income and relations but it can also cause infertility, if it infects the reproductive organs.

The TB bacteria can infect the fallopian tubes, endometrium, or ovaries, causing blockage, scarring, or poor implantation. In males, it can infect the testes or the ducts, causing poor sperm transport. But the real danger lies in its silent progression.

"The symptoms of genital TB are not usually obvious. They may present with irregular menstrual cycles, pelvic pain, infertility, scanty menstruation, unusual vaginal discharge, fever, weight loss, scrotal pain or swelling, scrotal masses, and infertility," said Dr Puneet Rana Arora, Director- Gynaecology & IVF Expert, CIFAR, Gurugram.

Infertility due to Genital Tuberculosis can usually be treated, but it depends on the extent of damage.

"The treatment of Genital Tuberculosis involves anti-tubercular treatment for a period of 6 to 9 months. Once the infection is cleared, there are various ways of restoring fertility. These are hormonal treatment, surgical correction if possible, or even IVF," Dr Arora explained.

In general, early diagnosis and rapid testing remain the key in battling and preventing TB from further spreading.

(Disclaimer: This content is for informational purposes only. Always seek the advice of a qualified medical practitioner with any questions about a medical condition.)