* received or contemplating any covid-19 vaccine or participated in a covid-19 vaccine trial. * subject is considered to be in their last few weeks of life prior to this acute illness. * history of pulmonary alveolar proteinosis. * history of hematopoietic stem cell transplant or solid organ transplant. * previous malignancy and lymphoproliferative disorders (within the last 5 years) with the exception of stable prostate cancer and basal cell carcinoma. * chronic obstructive pulmonary disease on long-term oxygen therapy - subjects with forced expiratory volume in 1 second known to be \<50% will also be excluded. * demyelinating disease. * known history of hepatitis b, hiv, or untreated hepatitis c infection * severe hepatic impairment or known cirrhosis - child-pugh score b or higher. * acute kidney injury stage 3 * tuberculosis or other severe infections such as (non-covid-19) sepsis, abscesses, fungal superinfection and opportunistic infections requiring treatment. * positive quantiferon gold test at screening * moderate or severe heart failure (new york heart association class iii/iv). * treatment with monoclonal antibodies targeting cytokines (e.g., tnf inhibitors \[adalimumab, infliximab, etanercept, golimumab, certolizumab\]; anti-il-1 \[e.g., anakinra, canakinumab\]; anti-il-6 or anti-il-6r \[e.g., tocilizumab, sarilumab, sitlukimab\]; or t-cells \[e.g., abatacept\]) in past 90 days (5 half-lives of the drug), or contemplating treatment with any of these agents during the trial period. * treatment with monoclonal antibodies targeting b-cells (e.g., rituximab, and including any targeting multiple cell lines including b-cells) in the 3 months prior to screening. * received gm-csf agents (e.g., sargramostim) within 2 months prior to screening. * treatment with other immunosuppressants in the 4 weeks prior to screening and in the judgment of the investigator, the risk of immunosuppression with adalimumab is larger than the risk of covid-19. * treatment with small molecule tyrosine kinase inhibitors (e.g., baricitinib, ibrutinib, acalabrutinib, imatinib, gefitinib), in the 4 weeks prior to screening. * received or contemplating receipt of any live vaccine or any investigational vaccine in the 4 weeks prior to screening. * current participation or previous participation in any other clinical trial within 30 days prior to randomization. * subjects with known hypersensitivity to adalimumab or excipients of adalimumab as stated in the label. * pregnant female * lactating female * women of childbearing potential who do not agree to either abstinence or use of at least one primary form of contraception (not including hormonal contraception) from the time of screening through day 29 following randomization.

* received or contemplating any covid-19 vaccine or participated in a covid-19 vaccine trial. * subject is considered to be in their last few weeks of life prior to this acute illness. * history of pulmonary alveolar proteinosis. * history of hematopoietic stem cell transplant or solid organ transplant. * previous malignancy and lymphoproliferative disorders (within the last 5 years) with the exception of stable prostate cancer and basal cell carcinoma. * chronic obstructive pulmonary disease on long-term oxygen therapy - subjects with forced expiratory volume in 1 second known to be \<50% will also be excluded. * demyelinating disease. * known history of hepatitis b, hiv, or untreated hepatitis c infection * severe hepatic impairment or known cirrhosis - child-pugh score b or higher. * acute kidney injury stage 3 * tuberculosis or other severe infections such as (non-covid-19) sepsis, abscesses, fungal superinfection and opportunistic infections requiring treatment. * positive quantiferon gold test at screening * moderate or severe heart failure (new york heart association class iii/iv). * treatment with monoclonal antibodies targeting cytokines (e.g., tnf inhibitors \[adalimumab, infliximab, etanercept, golimumab, certolizumab\]; anti-il-1 \[e.g., anakinra, canakinumab\]; anti-il-6 or anti-il-6r \[e.g., tocilizumab, sarilumab, sitlukimab\]; or t-cells \[e.g., abatacept\]) in past 90 days (5 half-lives of the drug), or contemplating treatment with any of these agents during the trial period. * treatment with monoclonal antibodies targeting b-cells (e.g., rituximab, and including any targeting multiple cell lines including b-cells) in the 3 months prior to screening. * received gm-csf agents (e.g., sargramostim) within 2 months prior to screening. * treatment with other immunosuppressants in the 4 weeks prior to screening and in the judgment of the investigator, the risk of immunosuppression with adalimumab is larger than the risk of covid-19. * treatment with small molecule tyrosine kinase inhibitors (e.g., baricitinib, ibrutinib, acalabrutinib, imatinib, gefitinib), in the 4 weeks prior to screening. * received or contemplating receipt of any live vaccine or any investigational vaccine in the 4 weeks prior to screening. * current participation or previous participation in any other clinical trial within 30 days prior to randomization. * subjects with known hypersensitivity to adalimumab or excipients of adalimumab as stated in the label. * pregnant female * lactating female * women of childbearing potential who do not agree to either abstinence or use of at least one primary form of contraception (not including hormonal contraception) from the time of screening through day 29 following randomization.

- received or contemplating any covid-19 vaccine or participated in a covid-19 vaccine trial. - subject is considered to be in their last few weeks of life prior to this acute illness. - history of pulmonary alveolar proteinosis. - history of hematopoietic stem cell transplant or solid organ transplant. - previous malignancy and lymphoproliferative disorders (within the last 5 years) with the exception of stable prostate cancer and basal cell carcinoma. - chronic obstructive pulmonary disease on long-term oxygen therapy - subjects with forced expiratory volume in 1 second known to be <50% will also be excluded. - demyelinating disease. - known history of hepatitis b, hiv, or untreated hepatitis c infection - severe hepatic impairment or known cirrhosis - child-pugh score b or higher. - acute kidney injury stage 3 - tuberculosis or other severe infections such as (non-covid-19) sepsis, abscesses, fungal superinfection and opportunistic infections requiring treatment. - positive quantiferon gold test at screening - moderate or severe heart failure (new york heart association class iii/iv). - treatment with monoclonal antibodies targeting cytokines (e.g., tnf inhibitors [adalimumab, infliximab, etanercept, golimumab, certolizumab]; anti-il-1 [e.g., anakinra, canakinumab]; anti-il-6 or anti-il-6r [e.g., tocilizumab, sarilumab, sitlukimab]; or t-cells [e.g., abatacept]) in past 90 days (5 half-lives of the drug), or contemplating treatment with any of these agents during the trial period. - treatment with monoclonal antibodies targeting b-cells (e.g., rituximab, and including any targeting multiple cell lines including b-cells) in the 3 months prior to screening. - received gm-csf agents (e.g., sargramostim) within 2 months prior to screening. - treatment with other immunosuppressants in the 4 weeks prior to screening and in the judgment of the investigator, the risk of immunosuppression with adalimumab is larger than the risk of covid-19. - treatment with small molecule tyrosine kinase inhibitors (e.g., baricitinib, ibrutinib, acalabrutinib, imatinib, gefitinib), in the 4 weeks prior to screening. - received or contemplating receipt of any live vaccine or any investigational vaccine in the 4 weeks prior to screening. - current participation or previous participation in any other clinical trial within 30 days prior to randomization. - subjects with known hypersensitivity to adalimumab or excipients of adalimumab as stated in the label. - pregnant female - lactating female - women of childbearing potential who do not agree to either abstinence or use of at least one primary form of contraception (not including hormonal contraception) from the time of screening through day 29 following randomization.

- received or contemplating any covid-19 vaccine or participated in a covid-19 vaccine trial. - subject is considered to be in their last few weeks of life prior to this acute illness. - history of pulmonary alveolar proteinosis. - history of hematopoietic stem cell transplant or solid organ transplant. - previous malignancy and lymphoproliferative disorders (within the last 5 years) with the exception of stable prostate cancer and basal cell carcinoma. - chronic obstructive pulmonary disease on long-term oxygen therapy - subjects with forced expiratory volume in 1 second known to be <50% will also be excluded. - demyelinating disease. - known history of hepatitis b, hiv, or untreated hepatitis c infection - severe hepatic impairment or known cirrhosis - child-pugh score b or higher. - acute kidney injury stage 3 - tuberculosis or other severe infections such as (non-covid-19) sepsis, abscesses, fungal superinfection and opportunistic infections requiring treatment. - positive quantiferon gold test at screening - moderate or severe heart failure (new york heart association class iii/iv). - treatment with monoclonal antibodies targeting cytokines (e.g., tnf inhibitors [adalimumab, infliximab, etanercept, golimumab, certolizumab]; anti-il-1 [e.g., anakinra, canakinumab]; anti-il-6 or anti-il-6r [e.g., tocilizumab, sarilumab, sitlukimab]; or t-cells [e.g., abatacept]) in past 90 days (5 half-lives of the drug), or contemplating treatment with any of these agents during the trial period. - treatment with monoclonal antibodies targeting b-cells (e.g., rituximab, and including any targeting multiple cell lines including b-cells) in the 3 months prior to screening. - received gm-csf agents (e.g., sargramostim) within 2 months prior to screening. - treatment with other immunosuppressants in the 4 weeks prior to screening and in the judgment of the investigator, the risk of immunosuppression with adalimumab is larger than the risk of covid-19. - treatment with small molecule tyrosine kinase inhibitors (e.g., baricitinib, ibrutinib, acalabrutinib, imatinib, gefitinib), in the 4 weeks prior to screening. - received or contemplating receipt of any live vaccine or any investigational vaccine in the 4 weeks prior to screening. - current participation or previous participation in any other clinical trial within 30 days prior to randomization. - subjects with known hypersensitivity to adalimumab or excipients of adalimumab as stated in the label. - pregnant female - lactating female - women of childbearing potential who do not agree to either abstinence or use of at least one primary form of contraception (not including hormonal contraception) from the time of screening through day 29 following randomization.