WO2021228768A1

WO2021228768A1 - Prevention of infectious diseases by modulating the immune system

Info

Publication number: WO2021228768A1
Application number: PCT/EP2021/062333
Authority: WO
Inventors: Leander Grode; Umesh Shaligram
Original assignee: Vakzine Projekt Management Gmbh
Priority date: 2020-05-11
Filing date: 2021-05-10
Publication date: 2021-11-18
Also published as: EP4149529A1

Abstract

The invention relates to a recombinant Mycobacterium cell for use in the prevention of an infectious disease. Particularly, the invention relates to the prevention or amelioration of a respiratory disorder caused by and/or associated with a virus infection, more particularly a Coronavirus infection.

Description

Prevention of infectious diseases by modulating the immune system

Description

SARS-CoV-2 spreads rapidly throughout the world. SARS-CoV-2 is being transmitted via droplets and fomites during close unprotected contact between an infector and infectee. Health-care workers face an elevated risk of exposure to - and infection in general and of - SARS-CoV-2. (Huang, C. et al. Clinical features of patients infected with 2019 novel coronavirus in Wuhan, China. Lancet (2020) doi:10.1016/S0140-6736(20)30183-5.).

A large epidemic does seriously challenge the available hospital capacity, and would be augmented by absenteeism of healthcare professionals. Because hospital personnel is limited, it is imperative to ensure the safety, health and fitness of existing hospital personnel in order to safeguard continuous patient care. Strategies to prevent absenteeism of healthcare professionals are, therefore, desperately needed.

Bacille Calmette-Guerin (BCG) is a vaccine against tuberculosis, with protective non-specific effects against other respiratory tract infections in in vitro and in vivo studies, and reported significant reductions in morbidity and mortality. (Benn, C. S., Netea, M. G., Selin, L. K. & Aaby, P. A Small Jab - A Big Effect: Nonspecific Immunomodulation By Vaccines. Trends in Immunology (2013) doi: 10.1016/j.it.2013.04.004.)

A recombinant BCG strain expressing a phagolysosomal escape domain is described in WO 99/101496, the content of which is herein incorporated by reference. The phagolysosomal escape domain enables the strain to escape from the phagosome of infected host cells by perforating the membrane of the phagosome. In order to provide an acidic phagosomal pH for optimal phagolysosomal escape activity, a urease-deficient recombinant strain was developed. This strain is disclosed in WO 2004/094469, the content of which is herein incorporated.

WO 2012/085101 , the content of which is herein incorporated, discloses that a recombinant BCG strain expressing membrane-perforating listeriolysin (Hly) of Listeria monocytogenes and devoid of urease C induces superior protection against aerogenic challenge with Mycobacterium tuberculosis { Mtb ) as compared to parental BCG in a preclinical model. Further, it is shown that both the recombinant and the parenteral strain induce marked Th1 immune responses, whilst only the recombinant BCG strain elicits are profound Th17 response in addition.

Tarancon et al (PLoS Pathog 16(4): e1008404) describe that the live attenuated tuberculosis vaccine MTBVAC induces trained immunity and confers protection against experimental lethal pneumonia elicited by administration of Streptococcus pneumoniae to mice. Miller et al (doi 10.1101/2020.03.24.20042937) describe a statistical correlation between universal BCG vaccination policy and reduced morbidity and mortality for COVID-19.

The present invention is based on a clinical human phase III study protocol, which provides evidence for the efficacy and safety of a recombinant urease- deficient and listeriolysin-expressing recombinant BCG strain in enhancing the immunity of a subject, particularly of a human subject, against a Coronavirus infection. This enhancement of the immunity leads to a prevention or an amelioration of the disease underlying the virus infection, e.g. COVID-19, including, but not limited to a shortening of the sickness time, a reduction of the occurrence and/or severity of symptoms and/or a reduction of mortality. A first aspect of the present invention is a pharmaceutical composition comprising a recombinant Mycobacterium cell, which comprises a recombinant nucleic acid molecule encoding a fusion polypeptide comprising:

(a) a domain capable of eliciting an immune response, and

(b) a phagolysosomal escape domain, for use in the prevention and/or amelioration of a respiratory disorder caused by and/or associated with a virus infection, particularly with a Coronavirus infection, and more particularly with a SARS-CoV-2 infection.

A further aspect of the present invention is a method for the prevention or amelioration of a respiratory disorder caused by and/or associated with a virus infection, particularly with a Coronavirus infection, and more particularly with a SARS-CoV-2 infection, in a subject in need thereof, comprising administering to said subject a pharmaceutical composition comprising a recombinant Mycobacterium cell, which comprises a recombinant nucleic acid molecule encoding a fusion polypeptide comprising:

(a) a domain capable of eliciting an immune response, and

(b) a phagolysosomal escape domain.

According to the present invention, a protocol is provided describing a phase III, double-blind, placebo-controlled, multi-center, clinical trial to assess the efficacy and safety of VPM1002 in reducing healthcare professionals absenteeism in the SARS-CoV-2 pandemic by modulating the immune system.

The protocol is designed to assess the reduction of absenteeism among healthcare professionals with direct patient contacts during the epidemic phase of COVID19. Further, the protocol is designed to assess the reduction of hospital admission, intensive care unit (ICU) admission or death in healthcare professionals with direct patient contacts during the epidemic phase of COVID19.

Further, according to the present invention interim results of a phase III, randomized, double-blind, placebo-controlled, multi-center clinical trial to assess the efficacy and safety of VPM1002 in reducing hospital admissions and/or severe respiratory infectious diseases among the elderly population in the SARS-CoV-2 pandemic by modulating the immune system are provided. These interim results indicate a slightly longer duration of severe respiratory disease in the placebo group compared to the VPM1002 group. Thus, prevention and/or amelioration of a respiratory disorder caused by and/or associated with a virus infection in the VPM1002 group can be reasonably expected as a final result.

Accordingly, the present invention further relates to the use of a pharmaceutical composition as described above for providing an immune- stimulatory effect when administered to a human subject, particularly to a human subject from a high-risk group such as hospital personnel, wherein said immune-stimulatory effect leads to a reduced susceptibility against a virus infection, particularly to a reduced susceptibility against a Coronavirus virus infection, and more particularly to a reduced susceptibility against a SARS-CoV-2 infection.

The reduced susceptibility against a virus infection results in the prevention and/or amelioration of a respiratory disorder caused by and/or associated with said virus infection. The virus may be any virus afflicting the mammalian, e.g. human respiratory system including the upper and lower airways. In certain embodiments, the virus is a Coronavirus. In further embodiments, the virus may an influenza virus or a Rhinovirus. The respiratory disorder relates to disorder afflicting the upper airways such as the oral cavity, the nasal cavity, the paranasal sinus, the pharynx and/or the throat, and/or the lower airways such as the bronchi and/or the lung.

According to certain embodiments of the invention, the reduced susceptibility to a SARS-CoV-2 infection leads to a prevention and/or amelioration of a Covid-19 disorder characterized by at least one of: a reduced infection rate, e.g. an infection rate reduced by at least 10%, at least 20%, at least 30%, at least 40% or at least 50% versus a control group; a reduced sickness or absence of work time due to a viral infection, e.g. a sickness or absence of work time reduced by at least 10%, at least 20%, at least 30%, at least 40% or at least 50% versus a control group; a reduced rate of COVID-19 symptoms such as increased temperature, e.g. fever of at least 38°C, and/or respiratory symptoms such as coughing and breathlessness, e.g. a rate of COVID-19 symptoms reduced by at least 10%, at least 20%, at least 30%, at least 40% or at least 50% versus a control group; a reduced rate of hospital admission, e.g. a rate of hospital admission reduced by at least 10%, at least 20%, at least 30%, at least 40% or at least 50% versus a control group; a reduced rate of ICU admission, e.g. a rate of ICU admission reduced by at least 10%, at least 20% or at least 30% versus a control group a reduced mortality rate, e.g. a mortality rate reduced by at least 10%, at least 20%, at least 30%, at least 40% or at least 50% versus a control group.

The term “control group” refers to a group, which has not been treated with the composition of the invention, e.g. which has been treated with placebo, and which is not statistically different from the treatment group, i.e. the group, which has been treated with the composition of the invention.

The active agent of the pharmaceutical composition is a live recombinant Mycobacterium cell, which comprises a recombinant nucleic acid molecule encoding a fusion polypeptide comprising (a) a domain capable of eliciting an immune response and (b) a phagolysosomal escape domain. The domain capable of eliciting an immune response is preferably an immunogenic peptide or polypeptide from a pathogen or an immunogenic fragment thereof. The Mycobacterium cell is preferably an M. bovis cell, an M. tuberculosis cell, particularly an attenuated M. tuberculosis cell or other Mycobacteria, e.g. M. microti, M. smegmatis, M. canettii, M. marinum or M. fortuitum. More preferably, the cell is an attenuated recombinant M. bovis (BCG) cell, particularly an M. bovis BCG cell, more particularly a recombinant M. bovis BCG cell from strain Danish subtype Prague (Brosch et al., Proc. Natl. Acad. Sci. USA, 104 (2007), 5396-5601). In an especially preferred embodiment, the Mycobacterium cell is recombinant urease-deficient. In an especially preferred embodiment the ureC sequence of the Mycobacterium cell is inactivated (AUrec), e.g. by constructing a suicide vector containing a ureC gene disrupted by a selection marker gene, e.g. the hygromycin gene, transforming the target cell with the vector and screening for selection marker-positive cells having a urease negative phenotype. In an even more preferred embodiment, the selection marker gene, i.e. the hygromycin gene, is subsequently inactivated. In this embodiment, the cell is a selection marker-free recombinant Mycobacterium cell. Most preferably, the cell is selection marker-free recombinant BCG strain Danish subtype Prague characterized as recombinant BCG AUrec::Hly+.

The domain capable of eliciting an immune response is preferably selected from immunogenic peptides or polypeptides from M. bovis, M. tuberculosis or M. leprae or from immunogenic fragments thereof having a length of at least 6, preferably at least 8 amino acids, more preferably at least 9 amino acids and e.g. up to 20 amino acids. Specific examples for suitable antigens are Ag85B (p30) from M. tuberculosis, Ag85B (a-antigen) from M. bovis BCG, Ag85A from M. tuberculosis and ESAT-6 from M. tuberculosis and fragments thereof. In other embodiments, the domain capable of eliciting an immune response is selected from non-Mycobacterium polypeptides.

More preferably, the immunogenic domain is derived from the antigen Ag85B. Most preferably, the immunogenic domain comprises the sequence from aa.41 to aa.51 in SEQ ID No.2. The recombinant nucleic acid molecule further comprises a phagolysosomal escape domain, i.e. a polypeptide domain which provides for an escape of the fusion polypeptide from the phagolysosome into the cytosol of mammalian cells. Preferably, the phagolysosomal escape domain is a Listeria phagolysosomal escape domain, which is described in US 5,733,151 , herein incorporated by reference. More preferably, the phagolysosomal escape domain is derived from the listeriolysin gene (Hly) of L. monocytogenes. Most preferably, the phagolysosomal domain is encoded by a nucleic acid molecule selected from: (a) a nucleotide sequence comprising nucleotides 211 -1722 as shown in SEQ ID No.1 , (b) a nucleotide sequence which encodes the same amino acid sequence as the sequence from (a), and (c) a nucleotide sequence hybridizing under stringent conditions with the sequence from (a) or (b).

Apart from the nucleotide sequence depicted in SEQ ID No.1 the present invention also comprises nucleic acid sequences hybridizing therewith. In the present invention the term "hybridization" is used as defined in Sambrook et al. (Molecular Cloning. A laboratory manual, Cold Spring Harbor Laboratory Press (1989), 1.101-1.104). In accordance with the present invention the term "hybridization" is used if a positive hybridization signal can still be observed after washing for one hour with 1 X SSC and 0.1 % SDS at 55°C, preferably at 62° C and more preferably at 68°C, particularly for 1 hour in 0.2 X SSC and 0.1 % SDS at 55°C, preferably at 62°C and more preferably at 68°C. A sequence hybridizing with a nucleotide sequence as per SEQ ID No.1 under such washing conditions is a phagolysosomal escape domain encoding nucleotide sequence preferred by the subject invention.

A nucleotide sequence encoding a phagolysosomal escape domain as described above may be directly obtained from a Listeria organism or from any recombinant source e.g. a recombinant E.coli cell containing the corresponding Listeria nucleic acid molecule or a variant thereof as described above. Preferably, the recombinant nucleic acid molecule encoding for a fusion polypeptide contains a signal peptide encoding sequence. More preferably, the signal sequence is a signal sequence active in Mycobacteria, preferably in M.bovis, e.g. a native M.bovis signal sequence. A preferred example of a suitable signal sequence is the nucleotide sequence coding for the Ag85B signal peptide, which is depicted in SEQ ID No.1 from nucleotide 1 to 120.

Further, it is preferred that a peptide linker be provided between the immunogenic domain and the phagolysosomal escape domain. Preferably, said peptide linker has a length of from 5 to 50 amino acids. More preferably, a sequence encoding a linker as shown in SEQ ID No.1 from nucleotide 154 to 210 or a sequence corresponding thereto as regards the degeneration of the genetic code.

The nucleic acid may be located on a recombinant vector. Preferably, the recombinant vector is a prokaryotic vector, i.e. a vector containing elements for replication or/and genomic integration in prokaryotic cells. Preferably, the recombinant vector carries the nucleic acid molecule of the present invention operatively linked with an expression control sequence. The expression control sequence is preferably an expression control sequence active in Mycobacteria, particularly in M.bovis. The vector can be an extrachromosomal vector or a vector suitable for integration into the chromosome. Examples of such vectors are known to the person skilled in the art and, for instance, given in Sambrook et al. supra.

The composition may administered to any subject, particularly a human subject, who is in risk of becoming infected with a pathogen, wherein the pathogen is particularly a virus, more particularly a Coronavirus, and even more particularly SARS-CoV-2. In certain embodiments, the composition is administered to a human subject, particularly to a human subject, who is a member of a high-risk group of being infected. In certain embodiments, the composition is administered to a human subject, who is a health-care professional, particularly a health-care professional working in a hospital, i.e. hospital personnel, and more particularly a health-care professional having direct contact with virus-infected patients, e.g. patients infected with SARS- CoV-2. The term “health-care professional” includes doctors, nurses, and other staff working in a hospital, as well RTV personnel, but also health care personnel working in private practices, nursing homes, retirement homes etc.

In certain embodiments, the composition is administered by injection, e.g. by subcutaneous, intramuscular or intradermal injection, particularly by intradermal injection. The composition is administered in an effective dose. For a human subject, the dose for an administration may be about 10⁴ to 10⁷ colony forming units (CFU), particularly about 10⁵ to 10⁶ CFU, and more particularly of about 2 x 10⁵ to 8 x 10⁵ CFU. In certain embodiments, the composition administered as a single dose. In further embodiments, the composition may be administered several times, e.g. at least 2 or 3 times, wherein the intervals between each administration may be at least one year, particularly between 3-5 years. Further, it is preferred to administer the composition without adjuvant.

The pharmaceutical composition comprises the recombinant Mycobacterial cell in living form. It may be a solid composition, e.g., a lyophilized or cryoconserved composition, which may be reconstituted with a suitable liquid carrier before use. In certain embodiments, the composition comprises a cryoprotectant, e.g. a carbohydrate such as glucose and/or dextran, and/or a polyalcohol. Alternatively, the preparation may be a liquid composition, e.g., a suspension.

Further, the invention is described in more detail by the following Figures and Examples.

The immunotherapeutic agent “VPM1002" used in these examples is recombinant M. bovis (BCG) Danish subtype Prague with an inactivated ureC sequence (AUrec) and without functional selection marker gene, which expresses an Ag85B/Hly fusion protein as shown in SEQ ID No.2 (Hly+). Example 1

A phase III, randomized, double-blind, placebo-controlled, multi-center, human clinical trial to assess the efficacy and safety of VPM1002 in reducing healthcare professionals’ absenteeism in the SARS-CoV-2 pandemic by modulating the immune system.

The trial design is schematically depicted in Figure 1 and described in detail as follows in Table 1.

PROTOCOL SYNOPSIS

Table 1

Example 2

Interim results of a phase III, randomized, double-blind, placebo- controlled, multi-center clinical trial to assess the efficacy and safety of VPM1002 in reducing hospital admissions and/or severe respiratory infectious diseases among the elderly population in the SARS-CoV-2 pandemic by modulating the immune system

Introduction

A total of 2038 adults aged 60 or above were planned to be enrolled across involved clinical trial sites in Germany. Informed consent was to be obtained from the subjects willing to take part in the trial. This was followed by assessment of the eligibility criteria. Subjects who fulfil the inclusion/exclusion criteria were to be centrally randomized in a 1:1 ratio to receive a single dose (0.1 ml) of either VPM 1002 or placebo, administered as an intradermal injection over the distal insertion of the deltoid muscle onto the humerus (approximately one third down the upper arm). Screening, randomization and administration of trial intervention was to occur on the same day. The reconstitution of trial intervention was done by unblinded site personnel who was not involved in the collection or evaluation of outcome data. Administration was done by blinded site personnel. Post vaccination, the subjects were observed at the trial site for at least 30 minutes.

Actually, 2065 subjects have been documented in the electronic case record form (eCRF), of whom 2038 were randomized and 2025 were vaccinated. The study enrollment is completed, however the 8 months follow-up period is still ongoing.

All subjects were requested to sign into a web-based tool designed for this trial. Every subject was encouraged to name a designated caregiver who may provide follow-up data in case of hospitalization or severe illness of the study subject. Designated caregivers were registered for and trained in the use of the web application. If the caregiver was not present at the screening visit informed consent, registration and training took place later but as soon as possible to assure continuous data entry. All subjects were followed-up entirely remotely. Subjects and caregivers were appropriately trained on the use of the web application and were informed regarding the various questionnaires and the timelines for completion of the same. The questionnaires were designed to collect data regarding hospitalization, adverse events (AE)/serious adverse events (SAE), intensive care unit (ICU) admissions and other secondary endpoints. In case the follow-up information is not completed weekly, subjects have received/will receive reminders within the web application.

Subjects have reported/will report all AEs and SAEs through the web application throughout the trial. The investigators have reviewed/will review the outcome and safety data. The subject may call/visit the investigator whenever required. Also depending on the condition/symptoms of the subject, the investigator may call the subject to the site to evaluate or obtain more detail.

Additionally, information on the occurrence of non-serious and serious AEs will be derived by non-directive questioning of the subject at monthly telephone calls during the trial (e.g. “Have you experienced any problems since your last contact?”), by subject report, or by observation. In addition, subjects are encouraged to complete a diary in the case they experience an AE until the AE has resolved.

If nasopharyngeal swabs or any other diagnostic test assessing a SARS- CoV-2 infection were performed in a setting not included in this trial, these test results should be recorded in the web application.

The duration of follow-up will be 240 days. Subjects with confirmed SARS- CoV-2 infection (with or without symptoms) have been/will be followed for at least 6 weeks (from the date of test result), independent of the total trial duration. All safety data that have been/are assessed during the weekly assessment after vaccination (with VPM1002 or Placebo) have been/will also be assessed during these 6 weeks. Subjects have received/will receive a notification via the web application at Day 240. The primary objective was to assess the reduction of days with severe respiratory infections at hospital and/or at home in elderly subjects during the pandemic of SARS-CoV-2.

Secondary objectives were to assess the reduction of disease severity, the duration of hospital admission, ICU admission, or death in elderly subjects during the pandemic of SARS-CoV-2.

Efficacy and Safety Variables

The primary efficacy parameter for this study is number of days with severe respiratory disease at hospital and/or at home The primary efficacy parameter was analyzed for the interim analysis, whereas all other variables are analyzed for the final analysis only.

Statistical Analysis Sets used for interim analysis

The Full Analysis Set (FAS) consists of all subjects which are randomly assigned to trial intervention and received a dose of trial intervention. Subjects will be analyzed according to the intervention they were assigned to during randomization. The FAS was considered the primary analysis set overall as well as for the interim analysis.

Interim analysis

The interim analysis was conducted after 9 weeks, after the last subject was randomized, to assess superiority. Primary endpoint data from all randomized subjects until the data base lock was used for the interim analysis. Due to this interim analysis and to keep the overall a-level of 0.05, this level was to be adjusted. O’Brien-Fleming boundaries were applied. Accordingly, a significance level of 0.048, 2-sided, is used for the final primary efficacy analysis. This O’Brien-Fleming method was applied to use only a very small amount of the significance level for the interim (0.005) and the majority of the 5% alpha for the final analysis.

Prior to the interim analysis a data soft lock was performed. Parameters have been checked as far as possible until data lock point 30Mar2021 , as specified in the data validation plan (DVP). The primary endpoint, number of days with severe respiratory disease at hospital and/or at home is reported as the average proportion of disease days with standard deviation. It was analyzed as counts per observation week (i.e. multiple observations per subject) using a negative binomial regression model with random intercept per subject and fixed effects for treatment, sex, site and observation week.

The primary endpoint number of days with severe respiratory disease at hospital and/or at home was derived from the subject diary by combining the number of days belonging to the following questions:

1 . “Have you been severely ill due to respiratory disease (bedridden at home without admission to a hospital)?” = “yes”

2. “Have you been treated in the hospital (one night or more)?” = “yes” and “Was the admission due to a severe respiratory disease?” = “yes”

The following hypothesis was tested:

H₀: number of days with severe respiratory disease at hospital and/or at home is equal in the VPM1002 and Placebo groups vs.

Hi: number of days with severe respiratory disease at hospital and/or at home is not equal in the VPM1002 and Placebo groups

The treatment effect of the model will be reported as a rate ratio (RR) with 99.5% confidence interval (Cl) for the interim analysis. The rate ratio will be calculated as the quotient of the adjusted mean values number of days with severe respiratory disease (as derived by a negative binomial model) of the Placebo group and the VPM1002 group. I.e., values of RR > 1 indicate more days of severe respiratory disease in Placebo compared to VPM1002.

A negative binomial model with logarithmic link function was fitted with the SAS® software.

No convergence could be achieved when running the statistical model using the SAS code pre-defined within the SAP. Therefore, the SAS code was slightly adjusted. The adaptations were limited to the following: • The estimation of the model was not based on default pseudolikelihood techniques but on an adaptive Gauss-Hermite quadrature method.

• Hence, the random effects were no longer specified as R-side effects.

Interim Analysis Results

2065 subjects were documented in the eCRF, of whom 2038 were randomized and 2025 were vaccinated. 2025 subjects (Placebo: 1013, VPM1002: 1012) are assigned to the FAS, i.e. were randomized and vaccinated. Any diary data used for the interim analysis of the primary endpoint was available for 2017 subjects, 1008 subjects in Placebo group and 1009 subjects in VPM1002 group.

There is no significant treatment effect observed (p=0.8085) when applying the negative binomial regression model with a random intercept per subject and fixed effects for treatment, sex, site and observation week to analyze the primary endpoint variable number of days with severe respiratory disease at hospital and/or at home.

The rate ratio (RR) of the mean number of days with severe respiratory disease between subjects of treatment group Placebo versus VPM1002 is 1.2152, indicating a higher mean number of days observed in the Placebo compared to VPM1002 group. The 99.5 confidence interval (Cl) is [0.1271 ; 11.6216]. The RR was calculated as the quotient of the estimated adjusted weekly mean values of 0.000005488 in Placebo and 0.000004516 in VPM1002. Very low values of adjusted weekly mean values arise due to the incomplete data status, as there are many patients with incomplete follow-up data at the current stage.

The mixed model was repeated including an interaction term between sex and treatment (trea sex) to detect a trend in sex-specific differences in treatment: The p-value on the interaction term was 0.8404, indicating there is no interaction between sex and treatment. Summary

The rate ratio of the mean number of days with severe respiratory disease indicate slightly longer disease duration in the Placebo group compared to the VPM1002 group. In view of this interim result, prevention and/or amelioration of a respiratory disorder caused by and/or associated with a virus infection in the VPM1002 group can be reasonably expected as a final result.

Claims

1. A pharmaceutical composition comprising a recombinant Mycobacterium bovis cell, wherein the cell comprises a recombinant nucleic acid molecule encoding a fusion polypeptide comprising:

(a) a domain capable of eliciting an immune response, and

(b) a Listeria phagolysosomal escape domain for use in the prevention and/or amelioration of a respiratory disorder caused by and/or associated with a virus infection.

2. The composition of claim 1 wherein the cell is a urease-deficient cell.

3. The composition of claim 1 or 2 wherein the cell is a recombinant M. bovis BCG cell from strain Danish subtype Prague.

4. The composition of any one of claims 1-3, wherein the domain capable of eliciting an immune response is selected from immunogenic peptides or polypeptides from M. bovis or M. tuberculosis.

5. The composition of any one of claims 1-4, wherein the recombinant nucleic acid molecule does not comprise any functional selection marker.

6. The composition of any one of claims 1 -5, wherein the fusion polypeptide comprises

(a) a domain capable of eliciting an immune response comprising the amino acid sequence from aa.41 to aa.51 in SEQ ID No.2, and

(b) a Listeria phagolysosomal escape domain encoded by a nucleic acid molecule selected from

(i) a nucleotide sequence comprising nucleotides 211 -1722 as shown in SEQ ID No.1 , (ii) a nucleotide sequence which encodes the same amino acid sequence as the sequence from (i), and

(iii) a nucleotide sequence hybridizing under stringent conditions with the sequence from (i) or (ii).

7. The composition of any one of claims 1-6, wherein the virus infection is a Coronavirus infection.

8. The composition of any one of claims 1-7, wherein the virus infection is an infection with SARS-CoV-2.

9. The composition of any one of claims 1-8, which is administered by injection, particularly by intradermal injection.

10. The composition of any one of claims 1-9, which is administered as a single dose.

11. The composition of any one of claims 1-10, which is administered in a dose of about 10⁴ to 10⁷ colony forming units (CFU), particularly of about 10⁵ to 10⁶ CFU, and more particularly of about 2 x 10⁵ to 8 x 10⁵

CFU.

12. The composition of any one of claims 1-11, which is administered to a human subject, particularly to a human subject, who is a member of a high-risk group

13. The composition of any one of claims 1-12, which is administered to a human subject, who is a health-care professional, particularly a healthcare professional working in a hospital.

14. The composition of any one of claims 1-13, wherein the viral infection is prevented or ameliorated by a modulation of the immune system.

15. The composition of any one of claims 1-14, wherein an immune- stimulatory effect is provided when the composition administered to a human subject, particularly to a human subject from a high-exposition group, wherein said immune-stimulatory effect leads to a reduced susceptibility against a virus infection, particularly to a reduced susceptibility against a Coronavirus virus infection, and more particularly to a reduced susceptibility to a SARS-CoV.2 infection.

16. A method for the prevention or amelioration of a respiratory disorder caused by and/or associated with a virus infection, particularly with a

Coronavirus infection, and more particularly with a SARS-CoV-2 infection, in a subject in need thereof, comprising administering to said subject a pharmaceutical composition comprising an effective dose of a recombinant Mycobacterium cell which comprises a recombinant nucleic acid molecule encoding a fusion polypeptide comprising:

(a) a domain capable of eliciting an immune response, and

(b) a phagolysosomal escape domain.