previous and concomitant therapy: 1. receipt of any vaccine (licensed or investigational) from 4 weeks before prime-2-cov_beta booster vaccination or anticipated vaccination during the study until 6 weeks after the prime-2-cov_beta booster vaccination 2. previous vaccination against covid-19 with vaccines (licensed or investigational) other than comirnaty 3. current or previous treatment with another investigational drug and/or medical device (within 30 days of enrollment or 5 half-lives of that investigational drug) 4. administration of immunoglobulins or any blood products within 2 months of prime-2-cov_beta booster vaccination 5. chronic administration of medication associated with impaired immune responsiveness as judged by the investigator (including, but not limited to: immunosuppressive therapy, systemic corticosteroids exceeding 10 mg/day of prednisone equivalent, allergy shots for hypo-sensitization, immunoglobulin, interferon, immunomodulators, cytotoxic drugs, or other similar or toxic drugs) within 2 months before the prime-2-cov_beta booster vaccination (day 1). inhaled/nebulized, intra-articular, intrabursal, or topical (skin or eyes) corticosteroids are permitted. previous and concomitant medical condition: 6. active sars-cov-2 infection, confirmed by a commercially available sars-cov-2 rapid antigen test at day 1, or currently on quarantine 7. confirmed (by real-time quantitative polymerase chain reaction) sars-cov-2 infection after 2nd vaccination with comirnaty 8. known history of severe adverse reactions to any vaccine and/or severe allergic reactions to any component of the study vaccine, to any drug, or to any other exposure 9. known history of angioedema 10. pregnant or lactating women 11. any confirmed or suspected immunosuppressive or immunodeficient condition 12. known history of guillain-barré syndrome 13. known infection with human immunodeficiency virus, hepatitis c virus or hepatitis b virus 14. active cancer (malignancy) within 5 years before day 1 (except for adequately treated non-melanomatous skin carcinoma, at the discretion of the investigator) 15. moderate or severe illness and/or fever \> 38.0 °c within 1 week before prime-2-cov_beta booster vaccination 16. any clinically significant health problem (medical history and physical examination) or clinically significantly abnormal finding in biochemistry and/or hematology blood tests, urinalysis, or electrocardiogram at screening according to the investigator's opinion 17. current or history of cardiovascular disease or structural cardiac disease (including chronic or congenital heart conditions, such as chronic hypertension, coronary heart disease, myocardial infarction and arrhythmias, hypertrophic cardiomyopathy, as well as a history of myocarditis after mrna vaccinations) 18. history of mrna vaccination-associated adverse events that were in nature and severity beyond the common aes expected 19. current or history of gastrointestinal disease, liver disease, renal disease or endocrine disorders, (including diabetes) and neurological illness (excluding migraine), when judged as clinically significant according to the investigator's opinion 20. current or history of chronic respiratory diseases, including mild asthma treated by on-demand medication (resolved childhood asthma is allowed) 21. current or history of alcohol and/or drug abuse within the last 6 months before day 1 previous and concomitant clinical study experience 22. current participation in another study or previous enrollment in this clinical study other exclusion criteria 23. investigator or employee of the study group or sponsor with direct involvement in the proposed study or relatives of the research staff with direct involvement in the proposed study 24. prolonged exposure to sheep or goats (e.g., shepherds, sheep farmer)

previous and concomitant therapy: 1. receipt of any vaccine (licensed or investigational) from 4 weeks before prime-2-cov_beta booster vaccination or anticipated vaccination during the study until 6 weeks after the prime-2-cov_beta booster vaccination 2. previous vaccination against covid-19 with vaccines (licensed or investigational) other than comirnaty 3. current or previous treatment with another investigational drug and/or medical device (within 30 days of enrollment or 5 half-lives of that investigational drug) 4. administration of immunoglobulins or any blood products within 2 months of prime-2-cov_beta booster vaccination 5. chronic administration of medication associated with impaired immune responsiveness as judged by the investigator (including, but not limited to: immunosuppressive therapy, systemic corticosteroids exceeding 10 mg/day of prednisone equivalent, allergy shots for hypo-sensitization, immunoglobulin, interferon, immunomodulators, cytotoxic drugs, or other similar or toxic drugs) within 2 months before the prime-2-cov_beta booster vaccination (day 1). inhaled/nebulized, intra-articular, intrabursal, or topical (skin or eyes) corticosteroids are permitted. previous and concomitant medical condition: 6. active sars-cov-2 infection, confirmed by a commercially available sars-cov-2 rapid antigen test at day 1, or currently on quarantine 7. confirmed (by real-time quantitative polymerase chain reaction) sars-cov-2 infection after 2nd vaccination with comirnaty 8. known history of severe adverse reactions to any vaccine and/or severe allergic reactions to any component of the study vaccine, to any drug, or to any other exposure 9. known history of angioedema 10. pregnant or lactating women 11. any confirmed or suspected immunosuppressive or immunodeficient condition 12. known history of guillain-barré syndrome 13. known infection with human immunodeficiency virus, hepatitis c virus or hepatitis b virus 14. active cancer (malignancy) within 5 years before day 1 (except for adequately treated non-melanomatous skin carcinoma, at the discretion of the investigator) 15. moderate or severe illness and/or fever \> 38.0 °c within 1 week before prime-2-cov_beta booster vaccination 16. any clinically significant health problem (medical history and physical examination) or clinically significantly abnormal finding in biochemistry and/or hematology blood tests, urinalysis, or electrocardiogram at screening according to the investigator's opinion 17. current or history of cardiovascular disease or structural cardiac disease (including chronic or congenital heart conditions, such as chronic hypertension, coronary heart disease, myocardial infarction and arrhythmias, hypertrophic cardiomyopathy, as well as a history of myocarditis after mrna vaccinations) 18. history of mrna vaccination-associated adverse events that were in nature and severity beyond the common aes expected 19. current or history of gastrointestinal disease, liver disease, renal disease or endocrine disorders, (including diabetes) and neurological illness (excluding migraine), when judged as clinically significant according to the investigator's opinion 20. current or history of chronic respiratory diseases, including mild asthma treated by on-demand medication (resolved childhood asthma is allowed) 21. current or history of alcohol and/or drug abuse within the last 6 months before day 1 previous and concomitant clinical study experience 22. current participation in another study or previous enrollment in this clinical study other exclusion criteria 23. investigator or employee of the study group or sponsor with direct involvement in the proposed study or relatives of the research staff with direct involvement in the proposed study 24. prolonged exposure to sheep or goats (e.g., shepherds, sheep farmer)

previous and concomitant therapy: receipt of any vaccine (licensed or investigational) from 4 weeks before prime-2-cov_beta booster vaccination or anticipated vaccination during the study until 6 weeks after the prime-2-cov_beta booster vaccination previous vaccination against covid-19 with vaccines (licensed or investigational) other than comirnaty current or previous treatment with another investigational drug and/or medical device (within 30 days of enrollment or 5 half-lives of that investigational drug) administration of immunoglobulins or any blood products within 2 months of prime-2-cov_beta booster vaccination chronic administration of medication associated with impaired immune responsiveness as judged by the investigator (including, but not limited to: immunosuppressive therapy, systemic corticosteroids exceeding 10 mg/day of prednisone equivalent, allergy shots for hypo-sensitization, immunoglobulin, interferon, immunomodulators, cytotoxic drugs, or other similar or toxic drugs) within 2 months before the prime-2-cov_beta booster vaccination (day 1). inhaled/nebulized, intra-articular, intrabursal, or topical (skin or eyes) corticosteroids are permitted. previous and concomitant medical condition: active sars-cov-2 infection, confirmed by a commercially available sars-cov-2 rapid antigen test at day 1, or currently on quarantine confirmed (by real-time quantitative polymerase chain reaction) sars-cov-2 infection after 2nd vaccination with comirnaty known history of severe adverse reactions to any vaccine and/or severe allergic reactions to any component of the study vaccine, to any drug, or to any other exposure known history of angioedema pregnant or lactating women any confirmed or suspected immunosuppressive or immunodeficient condition known history of guillain-barré syndrome known infection with human immunodeficiency virus, hepatitis c virus or hepatitis b virus active cancer (malignancy) within 5 years before day 1 (except for adequately treated non-melanomatous skin carcinoma, at the discretion of the investigator) moderate or severe illness and/or fever > 38.0 °c within 1 week before prime-2-cov_beta booster vaccination any clinically significant health problem (medical history and physical examination) or clinically significantly abnormal finding in biochemistry and/or hematology blood tests, urinalysis, or electrocardiogram at screening according to the investigator's opinion current or history of cardiovascular disease or structural cardiac disease (including chronic or congenital heart conditions, such as chronic hypertension, coronary heart disease, myocardial infarction and arrhythmias, hypertrophic cardiomyopathy, as well as a history of myocarditis after mrna vaccinations) history of mrna vaccination-associated adverse events that were in nature and severity beyond the common aes expected current or history of gastrointestinal disease, liver disease, renal disease or endocrine disorders, (including diabetes) and neurological illness (excluding migraine), when judged as clinically significant according to the investigator's opinion current or history of chronic respiratory diseases, including mild asthma treated by on-demand medication (resolved childhood asthma is allowed) current or history of alcohol and/or drug abuse within the last 6 months before day 1 previous and concomitant clinical study experience current participation in another study or previous enrollment in this clinical study other exclusion criteria investigator or employee of the study group or sponsor with direct involvement in the proposed study or relatives of the research staff with direct involvement in the proposed study prolonged exposure to sheep or goats (e.g., shepherds, sheep farmer)

previous and concomitant therapy: receipt of any vaccine (licensed or investigational) from 4 weeks before prime-2-cov_beta booster vaccination or anticipated vaccination during the study until 6 weeks after the prime-2-cov_beta booster vaccination previous vaccination against covid-19 with vaccines (licensed or investigational) other than comirnaty current or previous treatment with another investigational drug and/or medical device (within 30 days of enrollment or 5 half-lives of that investigational drug) administration of immunoglobulins or any blood products within 2 months of prime-2-cov_beta booster vaccination chronic administration of medication associated with impaired immune responsiveness as judged by the investigator (including, but not limited to: immunosuppressive therapy, systemic corticosteroids exceeding 10 mg/day of prednisone equivalent, allergy shots for hypo-sensitization, immunoglobulin, interferon, immunomodulators, cytotoxic drugs, or other similar or toxic drugs) within 2 months before the prime-2-cov_beta booster vaccination (day 1). inhaled/nebulized, intra-articular, intrabursal, or topical (skin or eyes) corticosteroids are permitted. previous and concomitant medical condition: active sars-cov-2 infection, confirmed by a commercially available sars-cov-2 rapid antigen test at day 1, or currently on quarantine confirmed (by real-time quantitative polymerase chain reaction) sars-cov-2 infection after 2nd vaccination with comirnaty known history of severe adverse reactions to any vaccine and/or severe allergic reactions to any component of the study vaccine, to any drug, or to any other exposure known history of angioedema pregnant or lactating women any confirmed or suspected immunosuppressive or immunodeficient condition known history of guillain-barré syndrome known infection with human immunodeficiency virus, hepatitis c virus or hepatitis b virus active cancer (malignancy) within 5 years before day 1 (except for adequately treated non-melanomatous skin carcinoma, at the discretion of the investigator) moderate or severe illness and/or fever > 38.0 °c within 1 week before prime-2-cov_beta booster vaccination any clinically significant health problem (medical history and physical examination) or clinically significantly abnormal finding in biochemistry and/or hematology blood tests, urinalysis, or electrocardiogram at screening according to the investigator's opinion current or history of cardiovascular disease or structural cardiac disease (including chronic or congenital heart conditions, such as chronic hypertension, coronary heart disease, myocardial infarction and arrhythmias, hypertrophic cardiomyopathy, as well as a history of myocarditis after mrna vaccinations) history of mrna vaccination-associated adverse events that were in nature and severity beyond the common aes expected current or history of gastrointestinal disease, liver disease, renal disease or endocrine disorders, (including diabetes) and neurological illness (excluding migraine), when judged as clinically significant according to the investigator's opinion current or history of chronic respiratory diseases, including mild asthma treated by on-demand medication (resolved childhood asthma is allowed) current or history of alcohol and/or drug abuse within the last 6 months before day 1 previous and concomitant clinical study experience current participation in another study or previous enrollment in this clinical study other exclusion criteria investigator or employee of the study group or sponsor with direct involvement in the proposed study or relatives of the research staff with direct involvement in the proposed study prolonged exposure to sheep or goats (e.g., shepherds, sheep farmer)

previous and concomitant therapy: receipt of any vaccine (licensed or investigational) from 4 weeks before prime-2-cov_beta booster vaccination or anticipated vaccination during the study until 6 weeks after the prime-2-cov_beta booster vaccination previous vaccination against covid-19 with vaccines (licensed or investigational) other than comirnaty current or previous treatment with another investigational drug and/or medical device (within 30 days of enrollment or 5 half-lives of that investigational drug) administration of immunoglobulins or any blood products within 2 months of prime-2-cov_beta booster vaccination chronic administration of medication associated with impaired immune responsiveness as judged by the investigator (including, but not limited to: immunosuppressive therapy, systemic corticosteroids exceeding 10 mg/day of prednisone equivalent, allergy shots for hypo-sensitization, immunoglobulin, interferon, immunomodulators, cytotoxic drugs, or other similar or toxic drugs) within 2 months before the prime-2-cov_beta booster vaccination (day 1). inhaled/nebulized, intra-articular, intrabursal, or topical (skin or eyes) corticosteroids are permitted. previous and concomitant medical condition: active sars-cov-2 infection, confirmed by a commercially available sars-cov-2 rapid antigen test at day 1, or currently on quarantine confirmed (by real-time quantitative polymerase chain reaction) sars-cov-2 infection after 2nd vaccination with comirnaty known history of severe adverse reactions to any vaccine and/or severe allergic reactions to any component of the study vaccine, to any drug, or to any other exposure known history of angioedema pregnant or lactating women any confirmed or suspected immunosuppressive or immunodeficient condition known history of guillain-barré syndrome known infection with human immunodeficiency virus, hepatitis c virus or hepatitis b virus active cancer (malignancy) within 5 years before day 1 (except for adequately treated non-melanomatous skin carcinoma, at the discretion of the investigator) moderate or severe illness and/or fever > 38.0 °c within 1 week before prime-2-cov_beta booster vaccination any clinically significant health problem (medical history and physical examination) or clinically significantly abnormal finding in biochemistry and/or hematology blood tests, urinalysis, or electrocardiogram at screening according to the investigator's opinion current or history of cardiovascular disease or structural cardiac disease (including chronic or congenital heart conditions, such as chronic hypertension, coronary heart disease, myocardial infarction and arrhythmias, hypertrophic cardiomyopathy, as well as a history of myocarditis after mrna vaccinations) history of mrna vaccination-associated aes that were in nature and severity beyond the common aes expected current or history of gastrointestinal disease, liver disease, renal disease or endocrine disorders, (including diabetes) and neurological illness (excluding migraine), when judged as clinically significant according to the investigator's opinion current or history of chronic respiratory diseases, including mild asthma treated by ondemand medication (resolved childhood asthma is allowed) current or history of alcohol and/or drug abuse within the last 6 months before day 1 previous and concomitant clinical study experience current participation in another study or previous enrollment in this clinical study other exclusion criteria investigator or employee of the study group or sponsor with direct involvement in the proposed study or relatives of the research staff with direct involvement in the proposed study prolonged exposure to sheep or goats (e.g., shepherds, sheep farmer)

previous and concomitant therapy: receipt of any vaccine (licensed or investigational) from 4 weeks before prime-2-cov_beta booster vaccination or anticipated vaccination during the study until 6 weeks after the prime-2-cov_beta booster vaccination previous vaccination against covid-19 with vaccines (licensed or investigational) other than comirnaty current or previous treatment with another investigational drug and/or medical device (within 30 days of enrollment or 5 half-lives of that investigational drug) administration of immunoglobulins or any blood products within 2 months of prime-2-cov_beta booster vaccination chronic administration of medication associated with impaired immune responsiveness as judged by the investigator (including, but not limited to: immunosuppressive therapy, systemic corticosteroids exceeding 10 mg/day of prednisone equivalent, allergy shots for hypo-sensitization, immunoglobulin, interferon, immunomodulators, cytotoxic drugs, or other similar or toxic drugs) within 2 months before the prime-2-cov_beta booster vaccination (day 1). inhaled/nebulized, intra-articular, intrabursal, or topical (skin or eyes) corticosteroids are permitted. previous and concomitant medical condition: active sars-cov-2 infection, confirmed by a commercially available sars-cov-2 rapid antigen test at day 1, or currently on quarantine confirmed (by real-time quantitative polymerase chain reaction) sars-cov-2 infection after 2nd vaccination with comirnaty known history of severe adverse reactions to any vaccine and/or severe allergic reactions to any component of the study vaccine, to any drug, or to any other exposure known history of angioedema pregnant or lactating women any confirmed or suspected immunosuppressive or immunodeficient condition known history of guillain-barré syndrome known infection with human immunodeficiency virus, hepatitis c virus or hepatitis b virus active cancer (malignancy) within 5 years before day 1 (except for adequately treated non-melanomatous skin carcinoma, at the discretion of the investigator) moderate or severe illness and/or fever > 38.0 °c within 1 week before prime-2-cov_beta booster vaccination any clinically significant health problem (medical history and physical examination) or clinically significantly abnormal finding in biochemistry and/or hematology blood tests, urinalysis, or electrocardiogram at screening according to the investigator's opinion current or history of cardiovascular disease or structural cardiac disease (including chronic or congenital heart conditions, such as chronic hypertension, coronary heart disease, myocardial infarction and arrhythmias, hypertrophic cardiomyopathy, as well as a history of myocarditis after mrna vaccinations) history of mrna vaccination-associated aes that were in nature and severity beyond the common aes expected current or history of gastrointestinal disease, liver disease, renal disease or endocrine disorders, (including diabetes) and neurological illness (excluding migraine), when judged as clinically significant according to the investigator's opinion current or history of chronic respiratory diseases, including mild asthma treated by ondemand medication (resolved childhood asthma is allowed) current or history of alcohol and/or drug abuse within the last 6 months before day 1 previous and concomitant clinical study experience current participation in another study or previous enrollment in this clinical study other exclusion criteria investigator or employee of the study group or sponsor with direct involvement in the proposed study or relatives of the research staff with direct involvement in the proposed study prolonged exposure to sheep or goats (e.g., shepherds, sheep farmer)