Empirical Assessment of Bacillus Calmette-Guérin Vaccine to Combat COVID-19

COVID-19 has become one of the critical health issues globally,which surfaced first in latter part of the year 2019.It is the topmost concern for many nations’governments as the contagious virus started mushrooming over adjacent regions of infected areas.In 1980,a vaccine called Bacillus Calmette-Guérin(BCG)was introduced for preventing tuberculosis and lung cancer.Countries that have made the BCG vaccine mandatory have witnessed a lesser COVID-19 fatality rate than the countries that have not made it compulsory.This paper’s initial research shows that the countries with a longtermcompulsory BCGvaccination system are less affected by COVID-19 than those without a BCG vaccination system.This paper discusses analytical data patterns for medical applications regarding COVID-19 impact on countries with mandatory BCG status on fatality rates.The paper has tackled numerous analytical challenges to realize the full potential of heterogeneous data.An analogy is drawn to demonstrate how other factors can affect fatality and infection rates other than BCG vaccination only,such as age groups affected,other diseases,and stringency index.The data of Spain,Portugal,and Germany have been taken for a case study of BCG impact analysis.

Expression and immunogenicity of recombinant Mycobacterium bovis Bacillus Calmette-Guérin strains secreting the antigen ESAT-6 from Mycobacterium tuberculosis in mice

Background Tuberculosis remains the leading cause of human death. Currently, Bacillus Calmette-Guerin （BCG） is the only available vaccine against tuberculosis but its efficacy is highly variable. Thus, developing new tuberculosis vaccines becomes an urgent task. In this study, we evaluated in BALB/c mice the humoral and cellular immune responses of recombinant BCG expressing the antigen ESAT-6 from Mycobacterium tuberculosis.Methods Escherichia coli-BCG shuttle plasmid named pDE22-esat-6 was constructed by inserting the BamHI/EcoRI digested esat-6 gene PCR product into the similarly digested parental plasmid pDE22. BCG cells were transformed with pDE22-esat-6, which was named recombinant BCG （rBCG）. BALB/c mice were immunized subcutaneously on the back with 100 μl normal saline containing 106 CFU of BCG or rBCG. They were sacrificed after 4 weeks to detect their humoral and cellular responses. Results There was no any significant differences in the growth characteristics between the conventional BCG and rBCG. In immunized mice, the IgG antibody titres of rBCG group were as high as 1：8000, which was significantly higher than that in BCG group （1：1400, P〈0.05）. The elicited IFN-γ, level of rBCG group was （1993 ± 106） pg/ml, which was also significantly higher than that in BCG group （（1463 ± 105） pg/ml, P〈0.05）. The splenocyte proliferation index of rBCG group reached 4.34 ± 0.31, which was higher than that of BCG group （3.79 ±0.24, P〈0.05）. Conclusion rBCG secreted expressing antigen ESAT-6 stimulated stronger humoral and cellular immune responses than BCG did, and, therefore may be the better vaccine against mycobacterium tuberculosis.

Antitumor effects of human interferon-alpha 2b secreted by recombinant bacillus Calmette-Guérin vaccine on bladder cancer cells

Objective:Our objective was to construct a recombinant bacillus Calmette-Guérin vaccine(rBCG) that secretes human interferon-alpha 2b(IFNα-2b) and to study its immunogenicity and in vitro antitumor activity against human bladder cancer cell lines T24 and T5637.Methods:The signal sequence BCG Ag85B and the gene IFNα-2b were amplified from the genome of BCG and human peripheral blood,respectively,by polymerase chain reaction(PCR).The two genes were cloned in Escherichia coli-BCG shuttle-vector pMV261 to obtain a new recombinant plasmid pMV261-Ag85B-IFNα-2b.BCG was transformed with the recombinant plasmid by electroporation and designated rBCG-IFNα-2b.Mononuclear cells were isolated from human peripheral blood(PBMCs) and stimulated with rBCG-IFNα-2b or wild type BCG for 3 d,and then cultured with human bladder cancer cell lines T24 and T5637.Their cytotoxicities were measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT) assay.Results:BCG was successfully transformed with the recombinant plasmid pMV261-Ag85B-IFNα-2b by electroporation and the recombinant BCG(rBCG-IFNα-2b) was capable of synthesizing and secreting cytokine IFNα-2b.PBMC proliferation was enhanced significantly by rBCG-IFNα-2b,and the cytotoxicity of PBMCs stimulated by rBCG-IFNα-2b to T24 and T5627 was significantly stronger in comparison to wild type BCG.Conclusions:A recombinant BCG,secreting human IFNα-2b(rBCG-IFNα-2b),was constructed successfully and was superior to control wild type BCG in inducing immune responses and enhancing cytotoxicity to human bladder cancer cell lines T24 and T5637.This suggests that rBCG-IFNα-2b could be a promising agent for bladder cancer patients in terms of possible reductions in both clinical dosage and side effects of BCG immunotherapy.

Reduced dose of Bacillus Calmette-Guérin versus full dose of Bacillus Calmette-Guérin for non-muscle-invasive bladder cancer after transurethral resection bladder tumor： a meta-analysis of randomized controlled trials

Background Bladder cancer is widely known as the most common malignant tumor in the urinary tract,with 75％-85％ of patients suffering from nonmuscle invasive bladder cancer （NMIBC）.However,the optimal dose of Bacillus Calmette-Guérin （BCG） remains controversial.The aim of this study was to compare the therapeutic efficacy of full dose （FD） with the reduced dose （RD） of BCG.Methods Randomized controlled trials （RCTs） were selected through the Cochrane Library,PubMed and Embase and were supplemented by hand searching of bibliographies.The end points include overall survival rate,recurrence rate,progression rate and side effects.Results Five RCTs that included a total of 1 473 patients （727 in the reduced dose group vs 746 in the full dose group）,with a median follow-up period from 33.5 month to 7.1 year.Disease in 80 of 687 （11.6％） patients assigned to the RD group progress to the muscular layer or distant metastasis,compared with 81 of 698 （11.6％） patients assigned to the FD group （RR=1.02; 95％ CI,0.77-1.36; P=0.89）.The incidence of recurrence at three year was reported in all five studies to be 41.1％ （299 of 727） and 36.1％ （269 of 746） in the RD and FD groups,respectively （RR=1.13; 95％ CI,1.00-1.29; P=0.05）.The 5-year survival rate was 75.9％ （502 of 662） in the RD group,and 75.8％ （510 of 673） in the FD group.In the RD group 41 of 655 （6.3％） patients and 56 of 663 （8.7％） patients in the FD group did not complete the treatment due to systemic or local side effects （RR=0.75; 95％ CI,0.51-1.10; P=0.14） Conclusions In general,the results of our study demonstrate a trend towards a reduction of the toxicity in reduced dose group without affecting the efficacy of treatment when compared with full dose.More trials with large sample size are still necessary to explore the prognosis of the patients with high risk of tumor in different dose group.

New insights into the effects of Mycobacterium bovis Bacillus Calmette-Guérin on asthma

Allergic asthma has been defined as a disease of immunodysregulation, where the pathology is a direct consequence of excessive T-helper type 2 immune responses （Th2） to allergens in the lungs. Disease is associated with increased secretion of type-2 cytokines such as interleukin （IL）-4, IL-5 and IL-13 which, among other things,

Treatment and disease management patterns for bacillus Calmette-Guérin unresponsive nonmuscle invasive bladder cancer in North America,Europe and Asia:A real-world data analysis

Background:This study examined real-world treatment and management of bacillus Calmette-Guérin(BCG)-unresponsive patients across 3 continents,including patients unable or unwilling to undergo cystectomy.Materials and methods:Physicians actively involved in managing patients with nonmuscle invasive bladder cancer completed online case report forms for their 5 consecutive patients from the broad BCG-unresponsive population and a further 5 consecutive BCG-unresponsive patients who did not undergo cystectomy(in Japan,physicians provided a total of 5 patients across both cohorts).Results:Most patients had received 1(37%)or 2(24%)maintenance courses of BCG.Five or more maintenance BCG courses were received by patients in Japan(59%)and China(31%),while in Germany 76%of patients received only 1 course.Most patients became BCG-unresponsive during their first(44%)or second(22%)treatment course;in Germany,77%became BCG-unresponsive during their first treatment course.Most countries did not provide another course of BCG after a patient first became unresponsive,whereas unresponsive patients in Japan and China were most likely to be retreated with BCG."Untreated-on watch and wait"was the main treatment/management approach received post-BCG treatment for 42%or more of patients in most countries except China(39%)and the United States(36%)."Following treatment guidelines"was consistently the top reason for post-BCG treatment selection across all treatment options.Conclusions:This study confirmed the global unmet need for patients with nonmuscle invasive bladder cancer,and found that many patients experienced periods of no treatment after not responding to BCG therapy.

The Effects of <i>Ganoderma lucidum</i>on Initial Events Related to the <i>Bacillus Calmette-Guérin</i>Efficacy and Toxicity on High-Risk Uroepithelial Cells: An <i>in Vitro</i>Preliminary Study

A novel prophylactic regimen is demanded for preventing bladder cancer recurrence, because of the high side-effect tolls of conventional adjuvant Bacillus Calmette-Guérin (BCG) immunotherapy, in addition to its only moderate efficacy. In vitro and animal studies have demonstrated the anti-cancer properties of a medicinal mushroom called Ganoderma lucidum (GL). In this study, a pre-malignant human uroepithelial cells (HUC-PC) model was utilized to compare the effectiveness between ethanol extract of GL (GLe) and BCG on interleukin-6 (IL-6) secretion and lactate dehydrogenase (LDH) cytotoxicity. Additionally, parameters relevant to the BCG efficacy and safety, including free soluble fibronectin (FN) and cell-surface glycosaminoglycans (GAGs) levels were tested, following the exposure of GLe to the cells. GLe at 100 μg/ml and BCG at 4.8 × 107 CFU were shown to induce equivalent levels of IL-6, suggesting the potential synergism, while the tested concentrations of GLe were non-cytotoxic. During the initial four hours of GLe exposure, the free FN concentrations in harvested media were significantly reduced that might facilitate the binding of BCG for uroepithelial internalization to enhance BCG efficacy. Furthermore, the cell membrane-bound GAGs levels of HUC-PC cells were significant increased in response to GLe to suggest cellular protection from BCG infection. In summary, current findings suggest the potential additive synergism of GLe with the BCG efficacy, as well as its protective effects, and thus reducing the BCG toxicity.

Granulomatous prostatitis after bacille Calmette-Guérin instillation resembles prostate carcinoma:A case report and review of the literature

BACKGROUND Bacille Calmette-Guérin(BCG)instillation is recommended in patients with nonmuscle-invasive bladder cancer who have intermediate-risk and high-risk tumors.However,granulomatous prostatitis is a rare complication induced by BCG instillation,which can easily be misdiagnosed as prostate cancer.Here,we report a case of granulomatous prostatitis that resembled prostate cancer.CASE SUMMARY A 64-year-old Chinese man with bladder cancer received BCG instillation.Three days later,he stopped BCG instillation and received anti-infective therapy due to the urinary tract infection.Three months after BCG restart,he had rising total prostate-specific antigen(PSA)(9.14 ng/mL)and decreasing free PSA/total PSA(0.09).T2-weighted images of magnetic resonance imaging(MRI)showed a 28 mm×20 mm diffuse low signal abnormality in the right peripheral zone,which was markedly hyperintense on high b-value diffusion-weighted MRI and hypointense on apparent diffusion coefficient map images.Considering Prostate Imaging Reporting and Data System score of 5 and possibility of prostate cancer,a prostate biopsy was conducted.Histopathology showed typical features of granulomatous prostatitis.The nucleic acid test for tuberculosis was positive.He was finally diagnosed with BCG-induced granulomatous prostatitis.Thereafter,he stopped BCG instillation and received anti-tuberculosis treatment.During 10 mo follow-up,he had no evidence of tumor recurrence or symptoms of tuberculosis.CONCLUSION Temporarily elevated PSA and high followed by low signal abnormality on diffusion-weighted MRI are important indicators of BCG-induced granulomatous prostatitis.

Nano-Bacillus Calmette-Guérin immunotherapies for improved bladder cancer treatment

Cancer immunotherapy has rapidly become the fourth mainstream treatment alternative after surgery,radiotherapy,and chemotherapy,with some promising results.It aims to kill tumor cells by mobilizing or stimulating cytotoxic immune cells.However,the clinical applications of tumor immunotherapies are limited owing to a lack of adequate delivery pathways and high toxicity.Recently,nanomaterials and genetic engineering have shown great potential in overcoming these limitations by protecting the delivery of antigens,activating targeted T cells,modulating the immunosuppressive tumor microenvironment,and improving the treatment efficacy.bacillus Calmette-Gué;rin(BCG)is a live attenuated Mycobacterium bovis vaccine used to prevent tuberculosis,which was first reported to have antitumor activity in 1927.BCG therapy can activate the immune system by inducing various cytokines and chemokines,and its specific immune and inflammatory responses exert antitumor effects.BCG was first used during the 1970s as an intravesical treatment agent for bladder cancer,which effectively improved immune antitumor activity and prevented tumor recurrence.More recently,nano-BCG and genetically engineered BCG have been proposed as treatment alternatives for bladder cancer due to their ability to induce stronger and more stable immune responses.In this study,we outline the development of nano-BCG and genetically engineered BCG for bladder cancer immunotherapy and review their potential and associated challenges.

Repeated inoculations of Mycobacterium bovis Bacille Calmette-Guérin (BCG) are needed to induce a strong humoral immune response against antigens expressed by the bacteria

The cellular immune response elicited by Mycobacterium bovis Bacille Calmette-Guérin (BCG) has been carefully investigated, but the humoral immune response has been partially neglected. BALB/c mice were immunized with BCG strain used to immunize humans. Anti-BCG antibodies, as assayed by ELISA, began to appear in the sera after the third week of immunization and plateaued three weeks after the 8th immunization. The total immunoglobulins (Igs) were purified by caprylic acid method from pooled serum collected after the 8th immunization. Anti-BCG antigen antibodies were detected in the total Igs preparation as well as in IgG, IgM, IgA, IgG1, IgG2a, and IgG2b, but not in the IgG3. Distinct BCG proteins were recognized the IgGs in Western blot analysis. Opsonization of BCG bacilli by the purified Igs potentiated internalization of the bacteria by murine Raw 264.7 macrophages. The intracellular BCG elimination coincided with the induction of NO production, which was more pronounced in cells infected with opsonized BCG compared to those infected with the non-opsonized bacteria. Coincidently, the production of NO was also higher in macrophages infected with opsonized BCG (maximal NO production at 48 h of incubation). The obtained results demonstrate that repeated inoculations of BCG effectively activate the humoral immune response, justifying the use of BCG as a live recombinant vaccine vector to insert genes encoding virulence factors controlled by antibodies.

How to reduce bacillus Calmette-Guerin discontinuation in patients with severe functional impairment

Background:Severe functional impairment is often considered a contraindication to intravesical therapy for nonmuscle-invasive bladder cancer(NMIBC).A tailored intravesical bacillus Calmette-Guérin(BCG)procedure was evaluated in high-risk(HR)-NMIBC patients with severe functional impairment.Materials and methods:Patients with a Katz Index score of 2 or less and an initial diagnosis of HR-NMIBC with atraumatic insertion of a Foley-type indwelling catheter,bladder emptying,and BCG instillation were prospectively treated;after 2 hours,the bladder was emptied and the catheter was removed(group A).After propensity score matching,52 patients in group A were compared with that of 52 consecutive patients in group B using a retrospective database,with similar baseline/oncological characteristics and treated with standard intermittent catheterization.Moreover,groups A and B were compared with that of 130 consecutive patients(group C)retrospectively evaluated,with similar oncological characteristics but with a Katz Index score of 3 or greater and treated with standard intermittent catheterization.Results:The discontinuation rates were 11.5%,35%,and 9%in groups A,B,and C,respectively(A vs.B,log-rank score 42.52[po<0.05];B vs.C,107.6[p<0.05];A vs.C,3.45[p>0.05]).The overall adverse event rates were 38.5%,57.7%,and 39.2%,respectively(A vs.B,p=0.04;B vs.C,0.03;A vs.C,0.92).The rates of severe adverse events were 1.9%,1.9%,and 1.5%,respectively,without statistically significant differences.The cumulative HR disease-free survival rates were 63.4%,48%,and 69.2%,respectively(A vs.B,log-rank score 154.9[p<0.05];B vs.C,415[p<0.05];A vs.C,244[p<0.05]).Conclusions:A tailored intravesical instillation procedure may reduce BCG discontinuation and adverse effects.

Cloning and expression of the fusion protein of interleukin-2 and ESAT6 in Mycobacterium bovis Bacillus Calmette Guérin strain

Tuberculosis (TB) is the most common cause of death in infectious diseases; it is estimated that approximately 2 million people per year die of TB. The present available TB vaccine is a live attenuated strain, Mycobacterium bovis Bacillus Calmette Guérin (BCG). However, it has been shown that BCG has variable protective efficacy, ranging from 0 to 85% in different clinical experiments. 1 Therefore, a new TB vaccine is urgently needed. Many trials have been done to develop the second-generation TB vaccines in recent years; candidates include avirulent, auxotrophic, subunit, DNA, and recombinant vaccines. 2 The outcomes of these vaccines disappointed investigators. Encouragingly, recombinant BCG, which overexpressed the mycobacterial antigen Ag85B, produced an excellent protective response, 3,4 suggesting that a vaccine based on recombinant BCG technique was a potential approach against TB.

新一代抗结核分枝杆菌疫苗将会建立在现用卡介苗的基础上吗?

本文针对以卡介苗(bacillus Calmette-Guérin,BCG)为基础的结核分枝杆菌新疫苗本身的缺陷问题、临床前药效学评价面临的问题、临床研究可能面临的有效性评价问题及伦理问题等,对"新一代抗结核分枝杆菌疫苗将会建立在现用BCG的基础上"的观点进行评述。认为以BCG为基础的新疫苗保护力可能超过现用BCG,但要显著提高其对成人的保护效果尚有难度;新疫苗用于新生儿的临床研究因存在伦理问题而可能无法开展;针对潜伏结核感染人群的免疫预防是控制结核病的重要手段,以现用BCG为基础的新疫苗可能无法应用于此类人群。因此,新一代主流抗结核分枝杆菌疫苗将不会是建立在现用BCG基础之上的疫苗。

婴幼儿淋巴结核病原体及多位点可变数目串联重复序列分析

为了解婴幼儿淋巴结核的主要病原体及其分子生物学信息，对分离自73例0～3岁淋巴结核患儿的79份淋巴结穿刺液阳性培养物进行结核分枝杆菌鉴定、3个不同区域片段（RD1、RD9、RD10）扩增及多位点可变数目串联重复序列分析（MLVA）。结果显示，婴幼儿淋巴结核以卡介苗（BCG）感染为主（95．9％），其次为人型结核分枝杆菌感染（4．1％）。通过MLVA分离出4个基因型，3个为独立基因型、1个为成簇基因型。76株属成簇基因型，均为BCG ；3个独立基因型均为人型结核分枝杆菌。研究表明，BCG是引起婴幼儿淋巴结核的主要病原体，临床分离的BCG MLVA分型无差异。

全球结核病疫苗研究进展

本文旨在对全球结核病疫苗研究进展进行系统综述,描述国际上目前进入临床试验不同阶段的新型疫苗,包括重组卡介苗、亚单位疫苗、治疗性疫苗等,分析我国结核病疫苗研究现状,介绍国际研究发展趋势,如人类疫苗计划、全细胞疫苗、多阶段疫苗等,并对存在的问题和挑战进行讨论,展望未来发展趋势。

抗膀胱癌新型制剂——重组卡介苗的研究

卡介苗(BCG)不仅是一种活疫苗,而且还是外源基因的表达载体和较强的免疫佐剂。基因重组卡介苗(rBCG)是借助分子生物学技术,将外源基因导入BCG中构建而成的多价疫苗。rBCG可诱导长期的体液免疫和细胞免疫,初步的研究结果已显示出rBCG具有广阔的应用前景,有望发展成为一种经济有效的新型疫苗,以预防传染病和一些肿瘤。本文结合作者最近的研究,就rBCG的构建、表达、特点、应用、存在的问题及应用前景等作一阐述。

Candidate Vaccines against Tuberculosis and the Future of Novel TB Vaccine Research

Introduction: Tuberculosis (TB) continues to be a global health challenge and currently only one licensed vaccine is available. For nearly 100 years, the Bacillus Calmette-Guérin (BCG) vaccine has been in use. While it provides protection against disseminated TB in infants, its protection against adult and adolescent pulmonary tuberculosis (PTB) is variable. This literature review will provide an overview of the clinical status of candidate TB vaccines and discuss the challenges and future development trends of novel TB vaccine research, in combination with a general overview of the Tuberculosis (TB) disease and Mycobacterium tuberculosis itself. Methods: Bibliographic searches were carried out on medical journal databases, publishers, and aggregators. The most used databases were PubMed, NCBI and MDPI. Publications in English on these and other databases relating to novel TB vaccines were included in this review. Results: Currently, there are 12 main vaccine candidates in various phases of clinical trials, they include four protein or adjuvant vaccines, three viral-vectored vaccines, three mycobacterial whole cells or extract vaccines, and one each of the recombinant life and the attenuated Mycobacterium tuberculosis vaccine. Currently, the most likely candidate vaccines are the M72 + AS01E and Vaccae vaccines. M72 + AS01E is a recombinant fusion protein vaccine candidate, clinical trials showed that administering two doses of M72/AS01E was successful in reducing the development of active TB disease with 50% efficacy. Studies have also proven the efficacy of Vaccae (which is currently in phase III clinical trials) as an adjunctive therapy, with it being curative in conjunction with current therapy. Conclusion: Given the morbidity and mortality suffered globally by M. tuberculosis, it is time to realize the seriousness of the situation and accelerate our commitment and investment to the eradication of this infectious disease. With the number of vaccine candidates currently in clinical trials having promising results, it is imperative to continue these studies and accelerate towards phase III licensure trials if we are to achieve the milestone of “End TB Strategy” by 2035. Today, we are witnessing immense progress in both preclinical and clinical TB vaccine research despite disappointing results from some of the clinical efficacy trials like that of MVA85A. We can revisit the design of vaccines and learn from them. It is important not only to recognize and give credit to those that have tested well in human trials, such as M72 + AS01E, but to expedite and improve its efficacy through funding of its research.

Septic Shock after Intravesical BCG Instillation—A Case Report

Bacillus Calmette-Guérin (BCG) is a live attenuated form of Mycobacterium bovis, initially used in medicine as a vaccination agent only. The discovery of its antineoplastic effects in bladder cancer has led to the widespread recognition of BCG intravesical instillation as a therapeutic option. Although sepsis following BCG intravesical instillation is rare, it is nonetheless a dreadful and potentially fatal complication. Therapy usually relies on antituberculous therapy and steroids, alongside with intensive care unit admission. The authors report a case of a 67-year-old male patient who developed septic shock with multiple organ dysfunction after intravesical BCG instillation and review the currently available knowledge concerning the risk factors, diagnosis, management and prevention of BCG sepsis.

BCG Infection after Bladder Cancer Treatment—3 Clinical Case Reports

Immunotherapy with Bacillus Calmette-Guérin (BCG) to treat non-muscle invasive bladder cancer has become an effective and superior alternative to chemotherapy. Intravesical treatment with BCG appears to be relatively safe;however, occasionally BCG infection complicates such treatment. In the present work we describe three patients in whom BCG infection occurred after intravesical BCG therapy. All patients had positive urine culture forMycobacterium tuberculosis complex, using AccuProbe culture identification and then Genotype Mycobacterium MTBC test identified Mycobacterium bovis BCG. The diagnosis is difficult and microbiologic study is usually negative, so high index of suspicion is essential.

Debate on Bacille Calmette-Guérin vaccination against COVID-19: Is it worth performing clinical trials?

The non-specific beneficial effects of Bacille Calmette-Guérin(BCG)vaccination suggest that this vaccine might play a role in protecting individuals against severe coronavirus disease 2019(COVID-19).Several studies propose that BCG vaccination may increase the body's immunity,thereby preventing respiratory infections caused by other respiratory pathogens.As the number of deaths due to COVID-19 is increasing rapidly and there is no specific treatment available to date,scientists are evaluating the effectiveness of already approved drugs as therapies against COVID-19,and the results were found to vary widely:from no significant effect being observed to a reduction in the time taken for clinical improvement.This study thus aims to evaluate whether it is worth performing clinical trials to examine the effects of the BCG vaccine on COVID-19.We herein emphasize the need to conduct phase III randomized controlled trials with adequate sample size and quality to investigate the effects of the BCG vaccine on COVID-19.In the event that BCG vaccination provides non-specific protection against COVID-19,administering it could be helpful in controlling the transmission of COVID-19 and other infectious diseases during future pandemics.