The humoral response after the fourth dose of a mRNA vaccine against COVID-19 has not been adequately described in elderly recipients, particularly those not exposed previously to SARS-CoV-2. Serum anti-RBD IgG levels (Abbott SARS-CoV-2 IgG II Quant assay) and neutralizing capacities (spike SARS-CoV-2 pseudovirus Wuhan and Omicron BA.1 variant) were measured after the third and fourth doses of a COVID-19 mRNA vaccine among 46 elderly residents (median age 85 years [IQR 81; 89]) of an assisted living facility. Among participants never infected by SARS-CoV-2, the mean serum IgG levels against RBD (2025 BAU/ml), 99 days after the fourth vaccine, was as high as 76 days after the third vaccine (1987 BAU/ml), and significantly higher (p = 0.030) when the latter were corrected for elapsed time. Neutralizing antibody levels against the historical Wuhan strain were significantly higher (Mean 1046 vs 1573; p = 0.002) and broader (against Omicron) (Mean 170 vs 375; p = 0.018), following the fourth vaccine. The six individuals with an Omicron breakthrough infection mounted strong immune responses for anti-RBD and neutralizing antibodies against the Omicron variant indicating that the fourth vaccine dose did not prevent a specific adaptation of the immune response. These findings point out the value of continued vaccine boosting in the elderly population

HIV/HCV prevention among people who inject drugs (PWID) is of key public health importance. We aimed to assess the impact of COVID-19 and associated response measures on HIV/HCV prevention services and socio-economic status of PWID in high-HIV-risk sites. Sites with recent (2011–2019) HIV outbreaks among PWID in Europe North America and Israel, that had been previously identified, were contacted early May 2020. Out of 17 sites invited to participate, 13 accepted. Semi-structured qualitative site reports were prepared covering data from March to May 2020, analyzed/coded and confirmed with a structured questionnaire, in which all sites explicitly responded to all 103 issues reported in the qualitative reports. Opioid maintenance treatment, needle/syringe programs and antiretroviral treatment /hepatitis C treatment continued, but with important reductions and operational changes. Increases in overdoses, widespread difficulties with food and hygiene needs, disruptions in drug supply, and increased homelessness were reported. Service programs rapidly reformed long established, and politically entrenched, restrictive service delivery policies. Future epidemic control measures should include mitigation of negative side-effects on service provision and socio-economic determinants in PWID.

According to World Health Organization WHO, Tuberculosis (TB) is the second cause of death from infectious disease worldwide. During 2021, 10.6 million people were infected with TB, and 1.6 million people died. TB is caused by pathogens belonging to the Mycobacterium tuberculosis complex (MTBC), mainly by Mycobacterium tuberculosis (M.tb). Members of this complex are acid-fast bacilli, which can cause intrapulmonary and extra pulmonary TB, and can be divided into various lineages, based on genomic markers. The main public health threat comes from drug resistant M.tb strains, which are responsible for about 25% of TB death and treatment failure worldwide. Treating drug resistant TB patients significantly raises the costs of TB treatment. This study provides an overview of the demographic and drug susceptibility characteristics of newly diagnosed TB patients in Israel in 2021. The State of Israel has a very low level of TB endemicity and is at a pre-elimination phase. Notably, only 11.7% of the newly diagnosed TB patients were born in Israel. In this report, of the 154 new laboratory-confirmed TB patients, 66.7% had pulmonary TB, while 16% had extrapulmonary TB. Males accounted for 52% of the patients, with the most prevalent age group being 21-40. Most patients were citizens of Israel (53.9%), while 37.7% had no Israeli citizenship. Among non-citizens, there was a predominance of males and patients aged 21-40. The susceptibility profile showed a high resistance rate to streptomycin (18.2%) and to a lower extent to isoniazid (13.6%), pyrazinamide (8.4%), rifampicin (7.8%), and ethambutol (3.2%). Only 2 cases of XDR-TB and 10 MDR-TB strains were detected in Israel in 2021, with both XDR strains and 5 out of 10 MDR strains belonging to the Beijing lineage. Most of Beijing isolates were resistant to at least one tested drug. Genomic sequencing of 134 out of 156 strains and bioinformatics analysis using the MTBseq program and WHO mutation catalogue shows a good match with only 9 discrepancies between phenotypic and genotypic susceptibility profiles in first line drugs. The most common lineage is Delhi-Cas (23%) followed by the Beijing lineage (17%). Most patients from the Delhi-Cas lineage were born in Africa, while patients with Beijing isolates were born in different countries. Minimum spanning tree analysis identified 15 clusters. The study highlights the need for ongoing surveillance of TB using molecular and phenotypic tools to further decreasing the spreading level of the disease and develop effective treatment strategies.

Despite the low prevalence of HIV-1 in Israel, continuous waves of immigration may have impacted the local epidemic. We characterized all people diagnosed with HIV-1 in Israel in 2010–2018. The demographics and clinical data of all individuals (n = 3639) newly diagnosed with HIV-1 were retrieved. Subtypes, transmitted drug-resistance mutations (TDRM), and phylogenetic relations, were determined in >50% of them. In 39.1%, HIV-1 transmission was through heterosexual contact; 34.3% were men who have sex with men (MSM); and 10.4% were people who inject drugs. Many (>65%) were immigrants. Israeli-born individuals were mostly (78.3%) MSM, whereas only 9% of those born in Sub-Saharan Africa (SSA), Eastern Europe and Central Asia (EEU/CA), were MSM. The proportion of individuals from SSA decreased through the years 2010–2018 (21.1% in 2010–2012; 16.8% in 2016–2018) whereas those from EEU/CA increased significantly (21% in 2010–2012; 27.8% in 2016–2018, p < 0.001). TDRM were identified in 12.1%; 3.7, 3.3 and 6.6% had protease inhibitors (PI), nucleotide reverse transcriptase inhibitors (NRTI), and non-nucleoside reverse transcriptase inhibitors (NNRTI) TDRM, respectively, with the overall proportion remaining stable in the studied years. None had integrase TDRM. Subtype B was present in 43.9%, subtype A in 25.2% (A6 in 22.8 and A1 in 2.4%) and subtype C in 17.1% of individuals. Most MSM had subtype B. Subtype C carriers formed small clusters (with one unexpected MSM cluster), A1 formed a cluster mainly of locally-born patients with NNRTI mutations, and A6 formed a looser cluster of individuals mainly from EEU. Israelis, <50 years old, carrying A1, had the highest risk for having TDRM. In conclusion, an increase in immigrants from EEU/CA and a decrease in those from SSA characterized the HIV-1 epidemic in 2010–2018. Baseline resistance testing should still be recommended to identify TDRM, and improve surveillance and care.

Access to HIV anti-retroviral treatment (ART) has significantly improved survival and the quality of life of people living with HIV (PLHIV). However, effective therapy necessitates high adherence to ART. The aim of this study was to identify the extent to which PLHIV in Israel were not retained in therapy and their obstacles to accessing care. The Department of Tuberculosis and AIDS (DTA) and the two existing HIV clinics in the Tel-Aviv metropolitan area performed a retrospective study for all PLHIV who were consulted at these clinics during 2008-2011, but were absent in 2012. From that population, 25% were randomly chosen for qualitative interviews. This study included 278 PLHIV not retained in care (13.4% of registered patients), of whom 194 (69.8%) were male, and 58.3% were Israeli citizens. Total number of clinic visits was 1959 (mean: 7.05 visits per patient; range: 1-39; SD: ±7.2) and the total person-years of follow-up for 267 PLHIV was 1,044 (mean: 3.9 py; 0-23; SD: ±4.4). Identified risk groups were: Originating from Generalized Epidemic countries (43.5%, 82.6% were non-Israelis); Men having Sex with Men (22.6%); Injecting Drug Users (12.9%) and Others (28.9%). Among Israelis, major reasons for clinic nonattendance included distance to the clinics and perceived lack of time. The major impediment to seeking care among undocumented migrants was lack of medical insurance. The DTA acted swiftly to make HIV-related services accessible to undocumented migrants. Barriers described by Israeli participants were generally more individual in nature, and should be addressed at the clinic level.

BACKGROUND:HIV Pre-exposure prophylaxis (PrEP) is the regular use of antiretroviral medication by people who are not infected with HIV to prevent seroconversion. Israel approved PrEP for continuous use in 2017, and Israeli Health Maintenance Organizations (HMO) offered PrEP with a copayment to eligible members. METHODOLOGY:This retrospective cohort study included all people who were dispensed PrEP between September 2017 to June 2019 in the second largest HMO in Israel. Statistical analysis, including Kaplan Meier, was conducted to evaluate user PrEP purchase, adherence to medical follow-up, and clinical outcomes. RESULTS:In total, a cohort of 757 PrEP users were followed for 657.8 person-years. All but one user were male; median age was 35 years. At baseline, 0.8% had gonorrhea and 1.5% had chlamydia infections and 4.4% had recent syphilis infection. Continuous use of PrEP (without interruption/discontinuation) was observed in 29.9%, while 39.9% interrupted and 30.3% discontinued use. Median time to first interruption/discontinuation was 4.0 months. At 6-12 months after initiation, 79.8% of users had a documented HIV test, 77.3% a Chlamydia-Gonorrhea panel, and 78.9% a creatinine test. There was one new case of HIV among the cohort, five months after PrEP discontinuation. Estimated first-year infection rates were 5.0%, 8.6% and 6.8% for gonorrhea, chlamydia and first-time syphilis, respectively. CONCLUSIONS:This study shows heterogeneous PrEP purchase patterns and required medical follow-up, and an increase in STIs among consistent PrEP users. Improving adherence to recommended medical follow-up during PrEP use is essential in PrEP's integration into Israel's national HIV prevention strategy.

BACKGROUND:Between 2011 and 2015, Men who have sex with men (MSM) accounted for nearly half of new HIV cases among men in Israel. This study carries out a cost-utility analysis of PrEP (HIV Pre Exposure Prophylaxis), an antiretroviral medication that can protect against the acquisition of HIV infection, whose incidence rate in Israel is around 1.74 per 1000 MSM.METHOD:Epidemiological, demographic, health service utilisation and economic data were integrated into a spread-sheet model in order to calculate the cost per averted disability-adjusted life year (DALY) of the intervention from a societal perspective, in mid-2018 US$ using a 3% discount rate. Cost utility analyses were performed for both types of PrEP delivery (continuous regimen and on-demand), together with sensitivity analyses on numbers of condom users who take up PrEP (baseline 25%) and subsequently abandon condom use (baseline 75%), PrEP efficacy (baseline 86%), PrEP prices and monitoring costs.RESULTS:Around 21.3% of MSM are high risk (as defined by having unprotected anal intercourse). Offering PrEP to this group would have a ten year net cost of around 1563 million USD, preventing 493 persons from becoming HIV-positive, averting around 1616 DALYs at a cost per averted DALY of around 967,744 USD. This will render the intervention to be not cost-effective. PrEP drug prices would have to fall dramatically (by 90.7%) for the intervention to become cost-effective (i.e. having a cost per averted DALY less than thrice GNP per capita) in Israel. PrEP remains not cost-effective (at 475,673 USD per averted DALY) even if intervention costs were reduced by using an "on demand" instead of a daily schedule. Even if there were no changes in condom use, the resultant 411,694 USD cost-utility ratio is still not cost-effective.CONCLUSIONS:Despite PrEPs high effectiveness against HIV, PrEP was found not to be cost-effective in the Israeli context because of a combination of relatively low HIV incidence, high PrEP costs, with a likelyhood that some low-risk MSM (ie: who use condoms) may well begin taking PrEP and as a consequence many of these will abandon condom use. Therefore, ways of minimizing these last two phenomena need to be found.

During 2011-16, HIV outbreaks occurred among people who inject drugs (PWID) in Canada (southeastern Saskatchewan), Greece (Athens), Ireland (Dublin), Israel (Tel Aviv), Luxembourg, Romania (Bucharest), Scotland (Glasgow), and USA (Scott County, Indiana). Factors common to many of these outbreaks included community economic problems, homelessness, and changes in drug injection patterns. The outbreaks differed in size (from under 100 to over 1000 newly reported HIV cases among PWID) and in the extent to which combined prevention had been implemented before, during, and after the outbreaks. Countries need to ensure high coverage of HIV prevention services and coverage higher than the current UNAIDS recommendation might be needed in areas in which short acting drugs are injected. In addition, monitoring of PWID with special attention for changing drug use patterns, risk behaviours, and susceptible subgroups (eg, PWID experiencing homelessness) needs to be in place to prevent or rapidly detect and contain new HIV outbreaks.

Despite considerable efforts to control tuberculosis (TB) among Ethiopian immigrants in Israel, an outbreak of TB among second-generation Ethiopian immigrants that involved native Israelis occurred between January 2011 and December 2019. The aim of this article is to report on this outbreak and discuss the patient and health system barriers that led to its propagation. Overall, 13 culture-positive TB patients were diagnosed in this outbreak. An additional 36 cases with identical mycobacterium tuberculosis genotypes were identified through cross-checking with the National TB Laboratory Registry. Among the 32 close contacts of the index case, 18 (56.3%) reported for screening and treatment of latent TB infection (LTBI) was recommended for 11 (61.1%) of them. However, none completed treatment and eight eventually developed TB. Of the 385 close contacts identified in this outbreak, 286 (74.3%) underwent contact investigation, 154 (53.8%) were recommended LTBI treatment, but only 26 (16.9%) completed the treatment. Routine contact investigation and treatment practice measures failed to contain the cascade of infection and disease, leading to the spread of the infecting strain of TB. This report highlights the challenges to identify the high-risk group and address barriers to care among such a vulnerable population.

Our aim was to assess the linkage to care (LTC) and treatment for people newly diagnosed with HIV in Israel during 2011–2015. The Ministry of Health estimated the annual prevalence of undiagnosed HIV; new diagnoses were identified by the Central Virology Laboratory. Only adult Israeli citizens were included. LTC at HIV centers within 90 days of diagnosis was assessed. Demographic and clinical data were collected from patient files. A total of 1538 individuals were diagnosed in 2011–2015. A moderate improvement over time was observed in the calculated proportions of undiagnosed individuals (23.1–17.3%) but no change occurred in LTC rates (82.6–81%). The proportion of diagnosed patients initiating treatment within six months increased from 54.7% in 2011 to 89.7% in 2015, with a parallel increase in the viral suppression rate from 30.5% in 2011 to 59.9% in 2015. Of 1159 patients with detailed records, 79.4% were men, median age 36 years (16–92), median CD4 cell count 342 cells/µl. Younger age, intravenous drug use, and imprisonment were independent risk factors for loss to follow-up. HIV is diagnosed late in Israel and LTC rates remain stagnated; higher awareness is still needed. Once in care, however, treatment and outcomes were in line with international standards.

Background: In TB low incidence countries , the outcome of TB treatment among non-citizen migrants from endemic countries affects ability to eliminate TB. This study compares TB treatment outcomes among non-citizen migrants in select pre-elimination country based on their policies for non-citizen migrant TB patients in order to determine how policy affects TB outcomes. Methods A literature review was conducted via PUBMED, MEDLINE (2000–2017) on TB policy among non-citizen migrants and treatment outcome. Treatment outcome among migrants diagnosed in Israel during 2000–2014 was analysed. Results In total, 18 publications met the inclusion criteria. All the countries reviewed except the United States offered free TB treatment to undocumented migrants. Successful TB treatment outcome for non-citizen migrants in Israel was 87%, the Netherlands was 90.7%, the UK was 82.1%, and outcomes in the US and Australia were not published. Conclusions There is a need to standardize results based on international definitions of migrants, asylum seekers, and refugees in order to determine status-specific barriers and to facilitate international comparisons. Policies insuring free access to TB care for non-citizen migrants are an important element for TB elimination in low incidence countries.

Background Undocumented migrants in Israel, mostly originating from HIV endemic countries, are not covered by Israel’s universal healthcare coverage. We initiated a Public-Private Partnership (PPP) to handle this public health and humanitarian challenge. The PPP venture included the Ministry of Health (MoH), pharmaceutical companies, pharmacies, and specialized HIV clinics, the Israeli HIV Medical Society (from the Israel Medical Association), and non-governmental organizations. This study describes the national policy process in conceptualizing and implementing access to HIV services for undocumented migrants through a PPP, and analyzes the preliminary results. Methods This case study describes the process of creating a temporary Public-Private Partnership to provide HIV care for undocumented migrants based on institutional records of the Department of Tuberculosis and AIDS (DTA) and memories and reflections from partners. This case was analyzed according to the OECD-DAC criteria for development assistance (relevance, effectiveness, efficiency, sustainability and impact). Demographic and serological data of patients referred between 2014 to 2018 were collected to monitor progress. and analyze preliminary medical and biological outcomes. Ethical approval was obtained from the Ministry of Health. Results Creating a policy to extend HIV care to undocumented migrants was a 15 year process that confronted several challenges within Israeli and international discourse, particularly concerning governmental response to the migration crisis. The use of a PPP model involving numerous stakeholders provided a solid, local feasibility demonstration that extending HIV care as a matter of policy would have positive implications for public health in Israel. During the first 2 years of the program (2014–2015), the MoH funded medical follow-up and the pharmaceutical companies provided antiretroviral treatment (ART) free of charge for only 100 patients at any given time, in addition to ART provided by the MoH for pregnant women. Since 2016, the MoH has fully covered this service and integrated it within the Israeli health system; this constitutes the major success of the PPP program. As of December 2018, the national program has monitored 350 patients and treated 316 (90.3%). The most prevalent disease present upon referral was Tuberculosis. Conclusions To our knowledge, this study documents the first example of a successful PPP with government partnership in a high-income country to address undocumented migrants’ lack of access to health services in general and HIV care in particular. In light of the intensification of North-South migration, this Israeli case study could be useful for other countries facing similar challenges. It also has lessons within Israel, as the country grapples with other health problems among uninsured communities.

Human immunodeficiency virus (HIV) transmission among women remains an issue in the WHO European Region, with nearly 50,000 women diagnosed in 2018 and over half (54%) diagnosed late. Although new HIV diagnoses declined between 2009 and 2018 in the West of the Region, they increased in the Centre and East. Understanding the characteristics of women diagnosed with HIV can inform gender-sensitive prevention services including pre-exposure prophylaxis and early testing and linkage to care.

BackgroundThis study is the first to describe major epidemiological trends and clinical characteristics among Israeli men who have sex with men (MSM), who are at a higher risk for HIV infection.MethodsThis retrospective study includes all individuals reported to the Israeli Ministry of Health with HIV and self-identified as MSM between 1981 and 2015. The incidence rates of HIV infection and AIDS-defining diseases were analyzed and Kaplan-Meier survival estimates were calculated from time of HIV infection notification to AIDS diagnosis and death across three consecutive periods representing antiretroviral treatment availability.ResultsThe trend of increase in HIV incidence is similar to Western Europe, although Israeli rates are lower. Of 2052 HIV/AIDS Israeli MSM diagnosed during the follow-up, 296 (14.6%) developed AIDS. MSM constitute 28.4% of all HIV/AIDS cases and 41.5% of cases among men. Average times from HIV-notification until AIDS diagnosis were 15.5 [14.0-16.9], 16.0 [15.5-16.4], and 6.7 [6.7-6.8] years, within 1981-1996, 1997-2007, and 2008-2015, respectively. The HIV-incidence rate among Israeli MSM slightly declined from 2012, after peaking in 2011 at 6.2 per 100,000.ConclusionsThe recent reduction in HIV-incidence and in AIDS diagnoses among Israeli MSM is encouraging. Nevertheless, the disproportionate incidence of HIV among MSM requires sustained efforts to abate further infections.

Background Highly active antiretroviral therapy (HAART) has changed life-expectancy and mortality trends among people living with HIV/AIDS (PLWHA) since 1996. This retrospective cohort study aimed to assess the mortality epidemiology of PLWHA in Israel and analyze the causes of death. Methods This cohort study included all adult Israeli-citizens PLWHA between 1985 and 2010 and crossed matched with the Civil Registry to identify those who died. Death certificates were classified into AIDS or non-AIDS deaths related-causes. Standardized mortality-ratio (SMR) represented mortality excess. Results Of all 5140 PLWHA who were followed-up for 36 955 person-years, 1066 (20.7%) died. The ratio of AIDS-related deaths to non-AIDS related deaths reduced from 1.2:1 before 1996 to 0.6:1 after 1997, and case-fatality rates reduced from 12.0 to 0.9%, respectively (P < 0.001). SMR were 3.0 (95% CI: 2.3-3.5) for males and 3.9 (95% CI: 3.3-4.5) for females. Fatality cases were more likely older Israeli-born males, co-infected with tuberculosis, reported before 1996 and acquired HIV by drug-injection or infected-blood products. Deaths of AIDS-related causes were common among Israeli-born gay men, while non-AIDS deaths were common among those reported after 1997 and drug users. Conclusions Death rates declined since HAART introduction. Yet, SMR remained high, and PLWHA infected by drug-use or blood-products have not enjoyed relative longevity.

Background: Fourth-generation immunoassays used for HIV screening, simultaneously detect anti-HIV antibodies and HIV-1 P24 antigen, but are prone to false-positive results. Usually, they are followed by highly specific third-generation assay, able to differentiate between HIV-1/2 infections. In Israel, screening algorithm is based on consecutive testing by two fourth-generation assays and confirmation by a third-generation test. Objectives: To evaluate the performance of this algorithm. Study design: Architect HIV1/2 Combo (Combo) reactive results were tested by Vidas HIV Duo Ultra (VD). Confirmation was by INNO-LIA HIV 1/2 or Geenius assays. Five-year results were retrospectively analyzed. HIV true positives (TPs), acute infected (AI), false-positives (FPs) and HIV negatives, were as defined by the algorithm. Results: 501,338 individuals were screened, of which 956 were TPs, 64 AI and 30 FPs. Specificity was almost 100% and positive predictive value 97%. VD was negative in 94% of confirmed Combo false-reactive individuals. The Combo results in the first tested sample differed substantially between TPs, AI and FPs, enabling the determination of a cutoff value that distinguished 94% of TPs and AI from FPs. Conclusions: An algorithm is suggested that will use a single sample collection. HIV negative diagnosis will be based on Combo unreactive or Combo reactive/VD negative results. HIV positive diagnosis will be based on Combo reactive/ VD positive results, given a Combo value above a designated cutoff. Below this cutoff samples will be tested by a molecular assay. Since HIV-2 rarely occurs in Israel, the use of a third-generation confirmation assay should be discussed.

Background: Architect (AR) and Vidas (VD) fourth generation HIV screening immunoassays, which identify early stages of HIV infections, could have false positive results especially at low signal/cutoff (S/C) AR values. Geenius HIV1/2 (GS) is a specific confirmation line immunoassay that is not highly sensitive to early HIV infections. An HIV-1 RNA assay may better detect such infections. Objectives: To evaluate all AR-VD reactive samples with GS results, and to assess Xpert Qual HIV-1 RNA assay (XQ) as an alternative to GS, in the first low S/C AR-VD-reactive samples from a tested individual. Study design: First AR-VD-reactive-GS-tested results from all individuals with resolved HIV status, collected between March 2015 and March 2017 (n = 749), were retrospectively assessed. Samples with AR-VD-reactive-GS-discordant results and those with low S/C AR-VD-reactive results, were tested by XQ. Receiver operating characteristic (ROC) analysis of GS and XQ sensitivity/specificity was performed. Results: Overall, 94.1% (705/749) of AR-VD-reactive results were true HIV-1 positive. All samples with < 3 S/C AR values were false positive. XQ resolved all first samples with AR-VD-reactive-GS-discordant results. The diagnostic accuracy of XQ in low (<= 33 S/C) AR-VD-reactive samples was better than that of GS (97.6%, 81/83 versus 73.5%, 61/83, p < 0.01). ROC analysis for low S/C AR samples was optimal for pooled XQ and GS results. Conclusions: Incorporating XQ in the current screening algorithm for the first AR-VD-reactive-GS-discordant samples may significantly reduce overall turn-around time of HIV-1 diagnosis.

Extensively drug-resistant (XDR) tuberculosis (TB) poses a threat to public health due to its complicated, expensive and often unsuccessful treatment. A cluster of three XDR TB cases was detected among foreign medical students of a Romanian university. The contact investigations included tuberculin skin testing or interferon gamma release assay, chest X-ray, sputum smear microscopy, culture, drug susceptibility testing, genotyping and whole-genome sequencing (WGS), and were addressed to students, personnel of the university, family members or other close contacts of the cases. These investigations increased the total number of cases to seven. All confirmed cases shared a very similar WGS profile. Two more cases were epidemiologically linked, but no laboratory confirmation exists. Despite all the efforts done, the source of the outbreak was not identified, but the transmission was controlled. The investigation was conducted by a team including epidemiologists and microbiologists from five countries (Finland, Israel, Romania, Sweden and the UK) and from the European Centre for Disease Prevention and Control. Our report shows how countries can collaborate to control the spread of XDR TB by exchanging information about cases and their contacts to enable identification of additional cases and transmission and to perform the source investigation.