Molecular confirmation of Bacillus Calmette Guerin vaccine related adverse events among Saudi Arabian children

Bacillus Calmette-Guérin Vaccine-Related Osteomyelitis in Immunocompetent Children in Saudi Arabia: A Narrative Review

The Bacillus Calmette-Guérin (BCG) vaccine is the most frequently used live-attenuated vaccine worldwide. Since 2002, two BCG vaccination strains, Pasteur 1173 P2 and Tokyo 172-1, have been the mainstay of Saudi Arabian healthcare. In 2005, the Danish 1331 strain was first used as the principal strain in clinical trials. Children can develop osteomyelitis 4-24 months after immunization with the BCG vaccine, an uncommon but serious side effect in immunocompetent children. We conducted this study to review the epidemiology, diagnosis, clinical symptoms, laboratory analyses, imaging features, and management of BCG osteomyelitis in immunocompetent children. Long bone metaphyses and epiphyses are more frequently affected. The diagnosis of BCG osteomyelitis is difficult because the symptoms are vague and subtle, and the duration between presentation and vaccination may range from a few months to a year. Radiography and computed tomography scans for BCG osteomyelitis typically show a devastating lesion with an associated periosteal response. Magnetic resonance imaging frequently reveals a large interosseous abscess indicative of osteomyelitis. There are no current treatment guidelines for BCG osteomyelitis in Saudi Arabia, but antituberculous regimens, particularly isoniazid and rifampicin, have been found to be very effective in previous studies. Although older studies did not favor surgical intervention because of the risk of complications, a few studies performed minor surgical interventions and had good outcomes. As BCG osteomyelitis is an infrequent complication, especially in immunocompetent children, its diagnosis is time-consuming. Therefore, it is critical to inform healthcare workers of this possible complication to make the diagnosis more straightforward and avoid confusion with pyogenic osteomyelitis. As only a few cases have been reported, further studies in Saudi Arabia are required for evidence-based guidelines applicable to actual practice to be established.

Primary Immunodeficiency Diseases and Bacillus Calmette-Guérin (BCG)-Vaccine-Derived Complications: A Systematic Review

BACKGROUND

Bacillus Calmette-Guérin (BCG) vaccine is a live attenuated bacterial vaccine derived from Mycobacterium bovis, which is mostly administered to neonates in regions where tuberculosis is endemic. Adverse reactions after BCG vaccination are rare; however, immunocompromised individuals and in particular patients with primary immunodeficiencies (PIDs) are prone to develop vaccine-derived complications.

OBJECTIVE

To systematically review demographic, clinical, immunologic, and genetic data of PIDs that present with BCG vaccine complications. Moreover, we performed a meta-analysis aiming to determine the BCG-vaccine complications rate for patients with PID.

METHODS

We conducted electronic searches on Embase, Web of Science, PubMed, and Scopus (1966 to September 2018) introducing terms related to PIDs, BCG vaccination, and BCG vaccine complications. Studies with human subjects with confirmed PID, BCG vaccination history, and vaccine-associated complications (VACs) were included.

RESULTS

A total of 46 PIDs associated with BCG-VAC were identified. Severe combined immunodeficiency was the most common (466 cases) and also showed the highest BCG-related mortality. Most BCG infection cases in patients with PID were reported from Iran (n = 219 [18.8%]). The overall frequency of BCG-VAC in the included 1691 PID cases was 41.5% (95% CI, 29.9-53.2; I² = 98.3%), based on the results of the random-effect method used in this meta-analysis. Patients with Mendelian susceptibility to mycobacterial diseases had the highest frequency of BCG-VACs with a pooled frequency of 90.6% (95% CI, 79.7-1.0; I² = 81.1%).

CONCLUSIONS

Several PID entities are susceptible to BCG-VACs. Systemic neonatal PID screening programs may help to prevent a substantial amount of BCG vaccination complications.

A systematic review of BCG vaccination policies among high-risk groups in low TB-burden countries: implications for vaccination strategy in Canadian indigenous communities

BACKGROUND

Bacille Calmette-Guérin (BCG) vaccination against tuberculosis (TB) is widespread in high-TB-burden countries, however, BCG vaccination policies in low-burden countries vary. Considering the uncertainties surrounding BCG efficacy and the lower likelihood of TB exposure in low-incidence countries, most have discontinued mass vaccination, choosing instead a targeted vaccination strategy among high-risk groups. Given the increased risk of TB infection in Canadian Indigenous communities compared to the general Canadian population, these communities are a pertinent example of high-incidence groups in an otherwise low-burden country, warranting particular consideration regarding BCG vaccination strategy. This systematic review aims to synthesise and critically appraise the literature on BCG vaccination strategies in high-risk groups in low-incidence settings to provide policy considerations relevant to the Canadian Indigenous context.

METHODS

A literature search of the Medline and Embase databases was conducted, returning studies pertaining to BCG vaccine efficacy, TB incidence under specific vaccination policies, BCG-associated adverse events, and vaccination policy guidelines in low-burden countries. Study screening was tracked using the Covidence systematic review software (Veritas Health Innovation, Melbourne, Australia), and data pertaining to the above points of interest were extracted.

RESULTS

The final review included 49 studies, spanning 15 countries. Although almost all of these countries had implemented a form of mass or routine vaccination previously, 11 have since moved to targeted vaccination of selected risk groups, in most cases due to the low risk of infection among the general population and thus the high number of vaccinations needed to prevent one case in the context of low-incidence settings. Regarding identifying risk groups for targeted screening, community-based (rather than individual risk-factor-based) vaccination has been found to be beneficial in high-incidence communities within low-incidence countries, suggesting this approach may be beneficial in the Canadian Indigenous setting.

CONCLUSIONS

Community-based vaccination of high-incidence communities may be beneficial in the Canadian Indigenous context, however, where BCG vaccination is implemented, delivery strategies and potential barriers to achieving adequate coverage in this setting should be considered. Where an existing vaccination program is discontinued, it is crucial that an effective TB surveillance system is in place, and that case-finding, screening, and diagnostic efforts are strengthened in order to ensure adequate TB control. This is particularly relevant in Canadian Indigenous and other remote or under-served communities, where barriers to surveillance, screening, and diagnosis persist.

Healthcare-Associated Mycobacterium bovis-Bacille Calmette-Guérin (BCG) Infection in Cancer Patients Without Prior BCG Instillation

Background

Bacille Calmette-Guérin (BCG), an attenuated strain of Mycobacterium bovis, is widely used as adjunctive therapy for superficial bladder cancer. Intravesical administration of BCG has been associated with systemic infection. Disseminated infection due to M. bovis is otherwise uncommon.

Methods

After identification of 3 patients with healthcare-associated BCG infection who had never received intravesical BCG administration, an epidemiologic study was performed. All patients with healthcare-associated BCG infection in the Barcelona tuberculosis (TB) program were reviewed from 1 January 2005 to 31 December 2015, searching for infections caused by M. bovis-BCG. Patients with healthcare-associated BCG infection who had not received intravesical BCG instillation were selected and the source of infection was investigated.

Results

Nine oncology patients with infection caused by M. bovis-BCG were studied. All had permanent central venous catheters. Catheter maintenance was performed at 4 different outpatient clinics in the same room in which other patients underwent BCG instillations for bladder cancer without required biological precautions. All patients developed pulmonary TB, either alone or with extrapulmonary disease. Catheter-related infection was considered the mechanism of acquisition based on the epidemiologic association and positive catheter cultures for BCG in patients in whom mycobacterial cultures were performed.

Conclusions

Physicians should be alerted to the possibility of TB due to nosocomially acquired, catheter-related infections with M. bovis-BCG in patients with indwelling catheters. This problem may be more common than expected in centers providing BCG therapy for bladder cancer without adequate precautions.

MIRU-profiler: a rapid tool for determination of 24-loci MIRU-VNTR profiles from assembled genomes of Mycobacterium tuberculosis

Background

Tuberculosis (TB) resulted in an estimated 1.7 million deaths in the year 2016. The disease is caused by the members of Mycobacterium tuberculosis complex, which includes Mycobacterium tuberculosis, Mycobacterium bovis and other closely related TB causing organisms. In order to understand the epidemiological dynamics of TB, national TB control programs often conduct standardized genotyping at 24 Mycobacterial-Interspersed-Repetitive-Units (MIRU)-Variable-Number-of-Tandem-Repeats (VNTR) loci. With the advent of next generation sequencing technology, whole-genome sequencing (WGS) has been widely used for studying TB transmission. However, an open-source software that can connect WGS and MIRU-VNTR typing is currently unavailable, which hinders interlaboratory communication. In this manuscript, we introduce the MIRU-profiler program which could be used for prediction of MIRU-VNTR profile from WGS of M. tuberculosis.

Implementation

The MIRU-profiler is implemented in shell scripting language and depends on EMBOSS software. The in-silico workflow of MIRU-profiler is similar to those described in the laboratory manuals for genotyping M. tuberculosis. Given an input genome sequence, the MIRU-profiler computes alleles at the standard 24-loci based on in-silico PCR amplicon lengths. The final output is a tab-delimited text file detailing the 24-loci MIRU-VNTR pattern of the input sequence.

Validation

The MIRU-profiler was validated on four datasets: complete genomes from NCBI-GenBank (n = 11), complete genomes for locally isolated strains sequenced using PacBio (n = 4), complete genomes for BCG vaccine strains (n = 2) and draft genomes based on 250 bp paired-end Illumina reads (n = 106).

Results

The digital MIRU-VNTR results were identical to the experimental genotyping results for complete genomes of locally isolated strains, BCG vaccine strains and five out of 11 genomes from the NCBI-GenBank. For draft genomes based on short Illumina reads, 21 out of 24 loci were inferred with a high accuracy, while a number of inaccuracies were recorded for three specific loci (ETRA, QUB11b and QUB26). One of the unique features of the MIRU-profiler was its ability to process multiple genomes in a batch. This feature was tested on all complete M. tuberculosis genome (n = 157), for which results were successfully obtained in approximately 14 min.

Conclusion

The MIRU-profiler is a rapid tool for inference of digital MIRU-VNTR profile from the assembled genome sequences. The tool can accurately infer repeat numbers at the standard 24 or 21/24 MIRU-VNTR loci from the complete or draft genomes respectively. Thus, the tool is expected to bridge the communication gap between the laboratories using WGS and those using the conventional MIRU-VNTR typing.

Disseminated Bacillus Calmette-Guérin (BCG) infections in infants with immunodeficiency

BACKGROUND

The Bacillus Calmette-Guérin (BCG) preparations are live-attenuated derivatives of Mycobacterium bovis. These products are used to vaccinate infants at birth, a practice that may result in a disseminated infection in those patients who have an unidentified immunodeficiency.

CASE PRESENTATION

Patients who were immunized at birth with BCG and who developed a disseminated infection are reported here to emphasize the importance of taking an extensive medical history before ‎giving the BCG vaccine. Patient 1 has a sibling who had familial hemophagocytic lymphohistiocytosis. Patient 2 has a severe immunodeficiency with profound lymphopenia. Patient 3 has a sibling who had a disseminated BCG infection. Patient 4 has two siblings with an immunodeficiency disorder; one sibling passed away in infancy and one is receiving regular immunoglobulin infusions. Patient 5 has profound lymphopenia and his brother had cytomegalovirus (CMV) pneumonitis and passed away in infancy.

CONCLUSIONS

These unfortunate events could have been avoided by compiling the relevant clinical and laboratory information. These cases also underscore the importance of a strict adherence to the BCG vaccine policies. Local and international registries that estimate the birth prevalence of primary immune deficiencies are needed prior to implementing universal BCG vaccination administration.

Prophylactic vaccines are potent activators of monocyte-derived dendritic cells and drive effective anti-tumor responses in melanoma patients at the cost of toxicity

Dendritic cell (DC)-based immunotherapy is explored worldwide in cancer patients, predominantly with DC matured with pro-inflammatory cytokines and prostaglandin E₂. We studied the safety and efficacy of vaccination with monocyte-derived DC matured with a cocktail of prophylactic vaccines that contain clinical-grade Toll-like receptor ligands (BCG, Typhim, Act-HIB) and prostaglandin E₂ (VAC-DC). Stage III and IV melanoma patients were vaccinated via intranodal injection (12 patients) or combined intradermal/intravenous injection (16 patients) with VAC-DC loaded with keyhole limpet hemocyanin (KLH) and mRNA encoding tumor antigens gp100 and tyrosinase. Tumor antigen-specific T cell responses were monitored in blood and skin-test infiltrating-lymphocyte cultures. Almost all patients mounted prophylactic vaccine- or KLH-specific immune responses. Both after intranodal injection and after intradermal/intravenous injection, tumor antigen-specific immune responses were detected, which coincide with longer overall survival in stage IV melanoma patients. VAC-DC induce local and systemic CTC grade 2 and 3 toxicity, which is most likely caused by BCG in the maturation cocktail. The side effects were self-limiting or resolved upon a short period of systemic steroid therapy. We conclude that VAC-DC can induce functional tumor-specific responses. Unfortunately, toxicity observed after vaccination precludes the general application of VAC-DC, since in DC maturated with prophylactic vaccines BCG appears to be essential in the maturation cocktail.

Adverse reactions to Mycobacterium bovis bacille Calmette-Guérin vaccination against tuberculosis in Iranian children

Purpose

There are considerable variations in the number of adverse reaction reports related to vaccine from different countries. The aim of this study was to review the development of adverse reactions to bacille Calmette-Guérin (BCG) vaccination among hospitalized patients in an Iranian referral hospital.

Materials and Methods

We identified hospitalized patients with BCG complications in Pediatric Infectious Disease Research Center, Tehran University of Medical Sciences, Tehran, Iran during January 2007-April 2009. Data on demographics, clinical features, laboratory findings, personal history (including vaccination history), family history, and outcomes were retrieved from medical records.

Results

There were 46 cases with BCG complication during the 2 years period. All of the children received vaccination at birth. Twenty-eight patients (61%) were male. The mean age of the patients was 13.5 ±11.3 months (range, 1 to 52 months; median, 10 months). The majority of children (57%) with BCG complication were less than 1 year old. Among hospitalized patients due to BCG complications, suppurative lymphadenitis was occurred in 28 children (61%) and lymphadenopathy was seen in 9 children (20%). Disseminated BCG was detected in 8 patients (17%) and only 1 child (2%) was presented with abscess. In 7% (n = 3) of children, the family history of BCG complications were positive.

Conclusion

The most common side effect of the BCG vaccine in our study was suppurative lymphadenitis. Disseminated BCG infection in complications leading to hospitalization in our study was 17%. With regard to the difficulty in implementing such a guideline in settings where BCG is given to all newborns, registration of Iranian primary immunodeficiency disorders (PID) patients would be helpful to increase the awareness of medical community of Iran to investigate underlying disease. In addition, BCG vaccination should postpone in each newborn with a family history of PID until the definite condition has been ruled out.