Guidance

Summary of TB contact tracing guidance

Published 6 October 2026

Summary of recommendations

All cases of pulmonary and laryngeal tuberculosis (infectious TB) should be considered index cases and as a minimum, their household and close contacts, irrespective of estimated contact duration, should be identified and offered testing for tuberculosis disease and infection ^{[footnote 1]}.

Contact tracing should be initiated in the following cases:

• confirmed cases of pulmonary or laryngeal TB, as indicated by a clinical specimen which is either culture ^{[footnote 2]} positive for M. tuberculosis complex organism or PCR positive ^{[footnote 3]} for M. tuberculosis complex
• clinical cases, defined as individuals without laboratory microbiological confirmation who have clinical and/or radiological evidence of pulmonary TB, and a clinician has started a full course of anti-TB therapy
• cases of TB in children aged under 16, regardless of the site of disease

Contact tracing is not routinely initiated in the following situations:

• cases that only meet the ‘possible’ case definition
• Non-Tuberculous Mycobacterial (NTM) infections

The estimated start of the infectious period for a pulmonary or laryngeal case of TB is 3 months before the onset of respiratory symptoms or 3 months before the first finding consistent with TB disease (such as abnormal chest x-ray), whichever is earlier ^{[footnote 4]}.

For drug-sensitive TB, completion of 2 weeks of effective treatment is conventionally regarded as the time point at which individuals will be rendered non-infectious. A risk assessment should be undertaken prior to hospital discharge to the community to consider any potential ongoing infectivity (for example, poor drug adherence or absorption, extensive disease or indicated by latest microbiology), the type of accommodation in which the person with TB will reside and the vulnerability of the individuals with whom they will reside.

When obtaining information on close contacts, a review should be undertaken to assess contacts beyond the household, which can include intimate partners, frequent visitors to the household, contacts in other congregate settings, and healthcare workers (when infection prevention and control procedures have not been observed).

Conduct contact tracing according to the concentric circle (stone-in-pond) approach, whereby contacts with greatest exposure to the index case or with vulnerability are prioritised for testing.

The first round of contact tracing for infectious TB should be for all household and close contacts. A risk assessment would then determine if a wider round of testing is required. If indicated, further rounds of testing are considered in contacts who have had a total cumulative contact time of 8 or more hours with the index case whilst they were infectious. This time may be reduced to 4 or more hours for vulnerable contacts. These time limits should be used as a guide, rather than a definitive metric, acknowledging the different risk profiles that exist, for both cases and contacts, and should be further informed by the local dynamic risk assessment and investigation outcomes.

Individuals with any of these clinical factors should be prioritised for contact tracing:

• pulmonary or laryngeal disease
• productive or frequent cough
• sputum smear positivity, short time-to-detection of Mycobacterium tuberculosis by culture and or high TB polymerase chain reaction (PCR) positivity
• radiologically extensive disease or presence of cavities on chest x-ray

Contact tracing should also be prioritised for the following situations :

• exposures in small, poorly-ventilated environments
• long durations of contact
• vulnerable contacts as described below

Vulnerable groups at greatest risk of progressing to active TB disease, and should be prioritised to be tested for TB Infection (LTBI) following exposure include:

• people with uncontrolled human immunodeficiency virus (HIV) infection
• young people
• older people ^{[footnote 5]}
• low weight
• immunosuppression related to co-morbidities (such as diabetes mellitus and chronic renal failure)
• immunosuppression related to pharmacological agents (some biological therapies, anti-rejection drugs for organ transplantation, chemotherapy and systemic steroids)

When considering wider screening beyond household and close contacts, consider convening an Incident Management Team (IMT) with relevant stakeholders. In this forum, a risk assessment should be undertaken to consider the infectiousness of the case, the location of the exposure and the duration of the exposure to the index case.

Where an IMT has been established, the IMT should agree when to conclude contact tracing and screening efforts. Should further cases subsequently be identified (particularly where linkage has been identified by WGS) a dynamic risk assessment should be undertaken, and further public health action considered.

Introduction

Tuberculosis (TB) is caused by bacteria of the Mycobacterium tuberculosis complex. It is spread predominantly by the respiratory route, where bacteria are aerosolised by people with pulmonary disease and are inhaled by susceptible individuals.

In 2024, a total of 5,490 people were notified with TB disease. The rate of notifications is now 9.4 per 100,000 population, just below the WHO threshold of 10 per 100,000 for a low incidence country.

Identifying close contacts following exposure to a case of infectious TB requires timely contact tracing with assessment for TB disease (active TB) or TB infection (Latent TB Infection) in those individuals. Contact tracing protects individuals who may have been exposed by offering preventative treatment as well as the wider population by interruption of transmission and preventing future illness. Contact tracing remains an important component of TB control as well as part of a core strategy for longer term TB elimination.

Who this guidance is for

This guidance is intended to be used for the Public Health management of TB Cases and their contacts. It is intended to replace sections of the 2016 National Institute for Health and Care Excellence (NICE) NG33 Guidance for the management of Tuberculosis (TB), which included limited guidance on wider public health actions in incidents and outbreaks outside of the household. Aspects of the NICE guidance not directly related to clinical care have been deprioritised by NICE and are expected to be withdrawn (2) whilst clinical recommendations are under review by NICE for update.

Epidemiological investigations and genetic typing, including WGS, and contact tracing in TB incident management have demonstrated that TB transmission does occur in a range of contexts outside of the household. This guidance is also intended as a complementary resource to the Royal College of Nursing (RCN) 2023 Case Management Tool for TB Prevention, Care and Control in the UK guidance, which is currently unavailable whilst it is being updated (3).

This document is for qualified professionals involved in the control of TB in England, including UK Health Security Agency (UKHSA) Health Protection Teams (HPTs) and other stakeholders, including NHS TB services, NHS hospital infection prevention and control (IPC) departments and NHS-led and commissioned occupational health services.

UKHSA is responsible for the provision of public health advice in England. The devolved nations (Wales, Scotland and Northern Ireland) have separate national public health agencies, whose guidance may diverge from that which is provided here.

This guidance focuses on the public health management of M. tuberculosis infection, and the general principles of contact tracing apply to human TB cases caused by both M. tuberculosis and the other Mycobacterium tuberculosis complex (MTBC) species. The zoonotic members (listed below) of the MTBC differ from M. tuberculosis in their epidemiology and geographical distributions, host ranges, clinical and drug resistance profiles.

TB in humans is caused by infection with bacteria of the M. tuberculosis complex, MTBC, (M. tuberculosis, M. bovis, M. africanum, M. microti, M. caprae, M. pinnipedii, M. canetti, M. orygis and M. mungi).

This document provides practical, operational guidance for HPTs undertaking risk assessments, identification, and prioritisation of contacts for contact tracing. It provides guidance for the public health management of TB in settings beyond the initial household and close contacts following the notification of a person with infectious TB who may have attended workplace, community and healthcare settings while infectious.

There is limited published evidence for contact tracing in TB. This guidance therefore presents a risk-assessment approach developed from expert opinion, national and international published guidelines and consensus documents.

These guidelines reflect the internal processes and procedures agreed within UKHSA. These guidelines cannot account for the individual circumstances of persons potentially exposed to TB or their medical history. They must be interpreted appropriately in the clinical context using professional judgment and, where necessary, with expert support.

Guidance development process

Review of evidence base

In 2019 a systematic review undertaken by the Cochrane Group aimed to establish evidence available to support the current ‘custom and practice’ approach to contact tracing, and whether alternative options could result in a higher rate of infection detection in contacts. However, the Cochrane review authors identified no studies of sufficient quality to address this question (4).

UKHSA evidence review

An evidence review was conducted within UKHSA to identify and assess the available randomised controlled trial (RCT) evidence for the effectiveness of contact tracing strategies in people exposed to a person with active TB in low TB incidence countries in 2023, and this was updated in 2026. No relevant RCTs were identified (5). Previous systematic reviews indicate that there are unlikely to be many observational studies on contact tracing in specific populations and the data available are likely to be derived from poor-quality studies (4, 6, 7).

UKHSA has also recently published a wider systematic review of the literature concerning the effectiveness of contact tracing to reduce transmission of infectious disease (including tuberculosis) as part of an epidemic or pandemic response. Its findings also identify inconsistent evidence for the effectiveness of contact tracing as well as high heterogeneity in study design.

Given these reviews, any conclusions that may be possible from a full review of the observational literature would be restricted by the limited numbers and quality of the available research studies. UKHSA will monitor published evidence and update the recommendations within this guidance accordingly.

There is an absence of recent published evidence. This guidance is synthesised from a range of international guidance and consensus documents in relation to contact tracing as detailed below. Where older guidance documents have been included, updates in line with more recent published evidence have been included and or expert opinion where appropriate.

Documents that have been used to support development of this guidance include:

• NICE guidance NG33: Tuberculosis (2) (withdrawn)
• Royal College of Nursing (2023) A Case Management Tool for TB Prevention, Care and Control in the UK (3) (withdrawn)
• British Association for Paediatric Tuberculosis (2023) Clinical Guidance: Care of children and young people exposed to or infected with tuberculosis (1)
• Centres of Disease Control (2005) Guidelines for the Investigation of Contacts of Persons with Infectious Tuberculosis - Recommendations from the National Tuberculosis Controllers Association and CDC (8)
• Health Protection Surveillance Centre (2010 (amended 2014)) Guidelines on the Prevention and Control of Tuberculosis in Ireland (9)
• Reducing tuberculosis transmission: a consensus document from the World Health Organization Regional Office for Europe (10)

Targeted searches of wider published evidence were also used to support the detail of contact tracing recommendations.

Expert consensus and review

A range of expert stakeholders (see section ‘Contributors’) co-developed the guidance or provided comments, ensuring expert opinion was utilised including where there are evidence gaps, to ensure guidance is grounded in current best practice. 

Further research is needed to determine whether alternative contact tracing approaches, including in specific different institutional settings, could increase the detection of contacts and infected individuals, and improve the cost effectiveness of contact tracing in these setting.

Stakeholder engagement

This guidance incorporates feedback received from stakeholders’ consultation on the draft guidance held in 2023. A sub-group of the working group from the UKHSA TB Unit reviewed stakeholders’ comments and collectively agreed revisions.

References

See the attached list of references for TB contact tracing guidance.

1. Note: Testing for TB infection (LTBI) is not routinely offered for contacts over 65 years of age. ↩

2. Culture positive cases in England will be confirmed and undergo WGS through the National Mycobacterial Reference Service (NMRS) or through the Wales Centre for Mycobacteria (depending on the location of the laboratory isolating the organism). ↩

3. If patient has not been treated for TB in the past – PCR positivity can last more than 2 years after the completion of appropriate treatment ↩

4. HPTs may, through their risk assessment, determine a more appropriate start point for contact tracing (considering settings, findings on household contact screening, symptom history and clinical advice, for example). ↩

5. Note: Testing for TB infection (LTBI) is not routinely offered for contacts over 65 years of age. ↩