What to Do After Being Exposed to Someone with Tuberculosis
If you've been in close contact with someone diagnosed with tuberculosis (TB), it's natural to be concerned about your health. While not everyone exposed to TB becomes infected, the bacteria that cause the disease—Mycobacterium tuberculosis—can spread through the air when an infected person coughs, sneezes, or speaks. Understanding what steps to take after exposure is essential for early detection and preventing potential transmission.
Recognizing Early Signs of TB Infection
After exposure, monitoring your health closely is crucial. Tuberculosis often presents with a range of systemic and respiratory symptoms. Common signs include persistent low-grade fever, especially in the afternoon or evening, night sweats (excessive sweating during sleep), unexplained fatigue, and unintentional weight loss. These are hallmark indicators of active TB infection.
Respiratory symptoms may also develop over time, such as a chronic cough lasting more than two to three weeks, production of sputum, coughing up blood (hemoptysis), chest discomfort, or shortness of breath. If you experience any combination of these symptoms following exposure, it's important to seek medical evaluation promptly.
Understanding TB Transmission and Risk Factors
It's important to note that TB is not easily transmitted. Prolonged and close contact—such as living in the same household or spending extended periods in enclosed spaces with an infected individual—increases the risk of transmission. Casual contact, like brief conversations or passing by someone on the street, poses minimal risk.
Individuals with weakened immune systems—due to conditions like HIV, diabetes, malnutrition, or long-term steroid use—are more susceptible to developing active TB after exposure. However, many people who inhale the bacteria only develop latent TB infection, meaning they carry the bacteria without showing symptoms and cannot spread it to others.
Diagnostic Testing for TB: What to Expect
If you've been exposed, healthcare providers typically recommend a series of diagnostic tests to determine whether you've been infected. These may include:
- PPD Skin Test (Tuberculin Skin Test): A small amount of purified protein derivative (PPD) is injected under the skin. A follow-up visit 48–72 hours later checks for a reaction, which may indicate TB exposure.
- Interferon-Gamma Release Assays (IGRAs): Blood tests such as QuantiFERON-TB Gold or T-SPOT.TB measure the immune system's response to TB bacteria and are highly specific, especially useful for those who've received the BCG vaccine.
- Sputum Tests: If symptoms are present, analyzing sputum samples through microscopy, culture, or nucleic acid amplification tests (like GeneXpert) can detect the presence of Mycobacterium tuberculosis. This remains the gold standard for diagnosing active pulmonary TB.
- TB Antibody and Molecular Tests: These newer methods help identify TB-specific antibodies or genetic material from the bacteria, supporting faster diagnosis.
The Role of Imaging in TB Diagnosis
Imaging studies play a vital role in evaluating suspected TB cases. A chest X-ray is usually the first step and can reveal abnormalities such as infiltrates, cavities, or nodules typical of TB infection. In some cases, a more detailed chest CT scan may be recommended to detect subtle lesions not visible on standard X-rays.
While imaging alone cannot confirm TB, it helps guide further testing and assesses the extent of lung involvement. When combined with clinical symptoms and lab results, radiological findings significantly improve diagnostic accuracy.
Next Steps: Prevention and Treatment Options
If testing confirms latent TB infection, your doctor may recommend preventive therapy—often involving medications like isoniazid or rifampin for several months—to reduce the risk of progressing to active disease. This is particularly important for high-risk individuals.
For those diagnosed with active TB, prompt treatment with a combination of antibiotics (typically isoniazid, rifampin, ethambutol, and pyrazinamide) for at least six months is essential to cure the infection and prevent drug resistance.
Remember, early intervention saves lives. If you've had close contact with a TB patient, don't wait for symptoms to appear. Consult a healthcare professional, get tested, and follow through with recommended care to protect both your health and public safety.