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The smallpox vaccine effectively induces immunity against mpox virus infection (formerly simian smallpox) in patients with human immunodeficiency virus (HIV) infection, although patients with lymphocyte counts below 500 cells/mm3 require booster doses, according to data from a study published in the Journal of Medical Virology.
The data come from the prospective observational study conducted by researchers at the Infection Biology Laboratory of the Department of Medicine and Life Sciences at Pompeu Fabra University and the HIV Unit of the Hospital del Mar Medical Research Institute in Barcelona, Spain. The investigators analyzed T-cell responses induced by vaccination with JYNNEOS.
Despite the substantial decrease in the reporting frequency of mpox cases from the global peak in August 2022 (30,894 cases) to 804 monthly cases in the last six months of 2023, mpox continues to circulate, and there is no specific vaccine. The JYNNEOS vaccine, with protective cross-reactivity against orthopoxviruses, is approved by the US Food and Drug Administration and the European Medicines Agency for the prevention of smallpox and mpox in adults at high risk for infection.
During the 2022 outbreak in the United States and Europe, vaccine shortages led to the emergency use authorization of a lower intradermal dose. This strategy was aimed at increasing vaccine supply up to fivefold.
Further clinical trials are needed to evaluate responses to JYNNEOS vaccination and compare different administration routes in patients with HIV infection. Protecting this population against mpox is a priority because people with high viral loads or loCD4+ T-lymphocyte counts are especially susceptible to severe disease.
Vaccination Responses
The study assessed the immune response to the JYNNEOS vaccine in patients with HIV who were receiving antiretroviral therapy as outpatients at the Infectious Diseases Unit of Hospital del Mar in Barcelona, Spain. Participants had viral loads controlled by antiretroviral therapy and CD4+ T-lymphocyte counts ≤ 500/mm3 (loCD4 group) or ≥ 500/mm3 (hiCD4 group) in blood. Vaccine responses were compared with those of vaccinated controls without the disease. The study included cases that received the standard subcutaneous vaccine (before August 2022) or the emergency dose-saving intradermal vaccine after its approval in August 2022.
The results demonstrated that the intradermal dose-saving vaccination route is preferable to the subcutaneous route and that patients in the loCD4 group may require at least one booster to generate an efficient response of specific T cells for mpox, wrote the authors.
“This study has two relevant points,” study author Robert Güerri-Fernandez, MD, PhD, head of infectious diseases at the Hospital del Mar Medical Research Institute, told this news organization. “In the subgroup of patients with HIV with effective treatment but without an immune response (ie, loCD4), the vaccine response is worse than in people who have recovered immunity or do not have HIV. Therefore, they need a booster dose.
“The second point is that the intradermal route with one-fifth of the standard subcutaneous dose has a better immune response than the standard subcutaneous route.” He added that it was a good strategy to save doses and be able to vaccinate many more people when vaccine shortages occurred.
“A general conclusion cannot be drawn,” he said. “It needs to be validated with many more subjects, of course, but in some way, it reinforced our confidence in the strategy of health authorities to promote intradermal vaccination. There we had evidence that the patients we were vaccinating intradermally were responding well.”
In Spain, although there is no shortage of vaccines today, they continue to be administered intradermally with a fractionated dose equivalent to one fifth of a standard dose, said Dr. Güerri-Fernandez.
However, in his opinion, observations regarding the two administration routes signal a need for further research. The main message should be that for patients with HIV infection who do not have an immune response, the vaccine response is incomplete, and they need booster doses as well as monitoring of the vaccine immune response, said Dr. Güerri-Fernandez.
More Studies Required
The research, which prospectively collected data and blood samples from patients with HIV who received the JYNNEOS vaccine, is small and included only 24 patients with HIV infection, with seven hospital workers who also received the vaccine and seven unvaccinated individuals as controls. “I am one of the control subjects of the study, and intradermal vaccination is not especially pleasant,” said Dr. Güerri-Fernandez. “It is a very innervated area, and the moment of introducing the liquid is uncomfortable. But it is perfectly bearable.”
Outpatient HIV-infected patients from the Infectious Diseases Unit of Hospital del Mar on antiretroviral therapy and with undetectable viral loads were grouped according to their CD4+ T-lymphocyte counts. Those with CD4+ T-lymphocyte counts ≤ 500/mm3 required at least one booster vaccine to exhibit efficient virus-specific T-lymphocyte responses. The magnitude of the T-cell response after this booster correlated directly with the CD4+ T-lymphocyte count of those vaccinated.
For Argentine infectious disease specialist Julián García, MD, clinical researcher at the Huésped Foundation in Buenos Aires, Argentina, who did not participate in the study, it is always productive to know that T-cell responses develop in patients with HIV infection, with CD4+ T-lymphocyte counts > and < 500/mm3, through an intradermal administration route.
Dr. García emphasized that the most novel aspect is that the JYNNEOS vaccine induces a specific T-cell response in patients with HIV infection that increases with higher CD4+ T-lymphocyte levels. However, he noted that the number of patients was less than 10 in most study groups, and the control group had only intradermal administration, which limits the interpretation of the results. “It will be necessary to verify this in studies with larger groups with control groups from all routes and with a correlate of protection.”
Dr. García referred to this latter point as a significant source of uncertainty. “The study is fundamentally based on the cellular response, but nowadays, there is no immune correlate of real-life protection.” He concluded that the study builds knowledge, which is essential for a vaccine that began to be used for mpox and the effectiveness of which is based on estimates.
Dr. Güerri-Fernandez and Dr. Garcia declared no relevant financial conflicts of interest.
This story was translated from the Medscape Spanish edition using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication. A version of this article appeared on Medscape.com.
The smallpox vaccine effectively induces immunity against mpox virus infection (formerly simian smallpox) in patients with human immunodeficiency virus (HIV) infection, although patients with lymphocyte counts below 500 cells/mm3 require booster doses, according to data from a study published in the Journal of Medical Virology.
The data come from the prospective observational study conducted by researchers at the Infection Biology Laboratory of the Department of Medicine and Life Sciences at Pompeu Fabra University and the HIV Unit of the Hospital del Mar Medical Research Institute in Barcelona, Spain. The investigators analyzed T-cell responses induced by vaccination with JYNNEOS.
Despite the substantial decrease in the reporting frequency of mpox cases from the global peak in August 2022 (30,894 cases) to 804 monthly cases in the last six months of 2023, mpox continues to circulate, and there is no specific vaccine. The JYNNEOS vaccine, with protective cross-reactivity against orthopoxviruses, is approved by the US Food and Drug Administration and the European Medicines Agency for the prevention of smallpox and mpox in adults at high risk for infection.
During the 2022 outbreak in the United States and Europe, vaccine shortages led to the emergency use authorization of a lower intradermal dose. This strategy was aimed at increasing vaccine supply up to fivefold.
Further clinical trials are needed to evaluate responses to JYNNEOS vaccination and compare different administration routes in patients with HIV infection. Protecting this population against mpox is a priority because people with high viral loads or loCD4+ T-lymphocyte counts are especially susceptible to severe disease.
Vaccination Responses
The study assessed the immune response to the JYNNEOS vaccine in patients with HIV who were receiving antiretroviral therapy as outpatients at the Infectious Diseases Unit of Hospital del Mar in Barcelona, Spain. Participants had viral loads controlled by antiretroviral therapy and CD4+ T-lymphocyte counts ≤ 500/mm3 (loCD4 group) or ≥ 500/mm3 (hiCD4 group) in blood. Vaccine responses were compared with those of vaccinated controls without the disease. The study included cases that received the standard subcutaneous vaccine (before August 2022) or the emergency dose-saving intradermal vaccine after its approval in August 2022.
The results demonstrated that the intradermal dose-saving vaccination route is preferable to the subcutaneous route and that patients in the loCD4 group may require at least one booster to generate an efficient response of specific T cells for mpox, wrote the authors.
“This study has two relevant points,” study author Robert Güerri-Fernandez, MD, PhD, head of infectious diseases at the Hospital del Mar Medical Research Institute, told this news organization. “In the subgroup of patients with HIV with effective treatment but without an immune response (ie, loCD4), the vaccine response is worse than in people who have recovered immunity or do not have HIV. Therefore, they need a booster dose.
“The second point is that the intradermal route with one-fifth of the standard subcutaneous dose has a better immune response than the standard subcutaneous route.” He added that it was a good strategy to save doses and be able to vaccinate many more people when vaccine shortages occurred.
“A general conclusion cannot be drawn,” he said. “It needs to be validated with many more subjects, of course, but in some way, it reinforced our confidence in the strategy of health authorities to promote intradermal vaccination. There we had evidence that the patients we were vaccinating intradermally were responding well.”
In Spain, although there is no shortage of vaccines today, they continue to be administered intradermally with a fractionated dose equivalent to one fifth of a standard dose, said Dr. Güerri-Fernandez.
However, in his opinion, observations regarding the two administration routes signal a need for further research. The main message should be that for patients with HIV infection who do not have an immune response, the vaccine response is incomplete, and they need booster doses as well as monitoring of the vaccine immune response, said Dr. Güerri-Fernandez.
More Studies Required
The research, which prospectively collected data and blood samples from patients with HIV who received the JYNNEOS vaccine, is small and included only 24 patients with HIV infection, with seven hospital workers who also received the vaccine and seven unvaccinated individuals as controls. “I am one of the control subjects of the study, and intradermal vaccination is not especially pleasant,” said Dr. Güerri-Fernandez. “It is a very innervated area, and the moment of introducing the liquid is uncomfortable. But it is perfectly bearable.”
Outpatient HIV-infected patients from the Infectious Diseases Unit of Hospital del Mar on antiretroviral therapy and with undetectable viral loads were grouped according to their CD4+ T-lymphocyte counts. Those with CD4+ T-lymphocyte counts ≤ 500/mm3 required at least one booster vaccine to exhibit efficient virus-specific T-lymphocyte responses. The magnitude of the T-cell response after this booster correlated directly with the CD4+ T-lymphocyte count of those vaccinated.
For Argentine infectious disease specialist Julián García, MD, clinical researcher at the Huésped Foundation in Buenos Aires, Argentina, who did not participate in the study, it is always productive to know that T-cell responses develop in patients with HIV infection, with CD4+ T-lymphocyte counts > and < 500/mm3, through an intradermal administration route.
Dr. García emphasized that the most novel aspect is that the JYNNEOS vaccine induces a specific T-cell response in patients with HIV infection that increases with higher CD4+ T-lymphocyte levels. However, he noted that the number of patients was less than 10 in most study groups, and the control group had only intradermal administration, which limits the interpretation of the results. “It will be necessary to verify this in studies with larger groups with control groups from all routes and with a correlate of protection.”
Dr. García referred to this latter point as a significant source of uncertainty. “The study is fundamentally based on the cellular response, but nowadays, there is no immune correlate of real-life protection.” He concluded that the study builds knowledge, which is essential for a vaccine that began to be used for mpox and the effectiveness of which is based on estimates.
Dr. Güerri-Fernandez and Dr. Garcia declared no relevant financial conflicts of interest.
This story was translated from the Medscape Spanish edition using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication. A version of this article appeared on Medscape.com.
The smallpox vaccine effectively induces immunity against mpox virus infection (formerly simian smallpox) in patients with human immunodeficiency virus (HIV) infection, although patients with lymphocyte counts below 500 cells/mm3 require booster doses, according to data from a study published in the Journal of Medical Virology.
The data come from the prospective observational study conducted by researchers at the Infection Biology Laboratory of the Department of Medicine and Life Sciences at Pompeu Fabra University and the HIV Unit of the Hospital del Mar Medical Research Institute in Barcelona, Spain. The investigators analyzed T-cell responses induced by vaccination with JYNNEOS.
Despite the substantial decrease in the reporting frequency of mpox cases from the global peak in August 2022 (30,894 cases) to 804 monthly cases in the last six months of 2023, mpox continues to circulate, and there is no specific vaccine. The JYNNEOS vaccine, with protective cross-reactivity against orthopoxviruses, is approved by the US Food and Drug Administration and the European Medicines Agency for the prevention of smallpox and mpox in adults at high risk for infection.
During the 2022 outbreak in the United States and Europe, vaccine shortages led to the emergency use authorization of a lower intradermal dose. This strategy was aimed at increasing vaccine supply up to fivefold.
Further clinical trials are needed to evaluate responses to JYNNEOS vaccination and compare different administration routes in patients with HIV infection. Protecting this population against mpox is a priority because people with high viral loads or loCD4+ T-lymphocyte counts are especially susceptible to severe disease.
Vaccination Responses
The study assessed the immune response to the JYNNEOS vaccine in patients with HIV who were receiving antiretroviral therapy as outpatients at the Infectious Diseases Unit of Hospital del Mar in Barcelona, Spain. Participants had viral loads controlled by antiretroviral therapy and CD4+ T-lymphocyte counts ≤ 500/mm3 (loCD4 group) or ≥ 500/mm3 (hiCD4 group) in blood. Vaccine responses were compared with those of vaccinated controls without the disease. The study included cases that received the standard subcutaneous vaccine (before August 2022) or the emergency dose-saving intradermal vaccine after its approval in August 2022.
The results demonstrated that the intradermal dose-saving vaccination route is preferable to the subcutaneous route and that patients in the loCD4 group may require at least one booster to generate an efficient response of specific T cells for mpox, wrote the authors.
“This study has two relevant points,” study author Robert Güerri-Fernandez, MD, PhD, head of infectious diseases at the Hospital del Mar Medical Research Institute, told this news organization. “In the subgroup of patients with HIV with effective treatment but without an immune response (ie, loCD4), the vaccine response is worse than in people who have recovered immunity or do not have HIV. Therefore, they need a booster dose.
“The second point is that the intradermal route with one-fifth of the standard subcutaneous dose has a better immune response than the standard subcutaneous route.” He added that it was a good strategy to save doses and be able to vaccinate many more people when vaccine shortages occurred.
“A general conclusion cannot be drawn,” he said. “It needs to be validated with many more subjects, of course, but in some way, it reinforced our confidence in the strategy of health authorities to promote intradermal vaccination. There we had evidence that the patients we were vaccinating intradermally were responding well.”
In Spain, although there is no shortage of vaccines today, they continue to be administered intradermally with a fractionated dose equivalent to one fifth of a standard dose, said Dr. Güerri-Fernandez.
However, in his opinion, observations regarding the two administration routes signal a need for further research. The main message should be that for patients with HIV infection who do not have an immune response, the vaccine response is incomplete, and they need booster doses as well as monitoring of the vaccine immune response, said Dr. Güerri-Fernandez.
More Studies Required
The research, which prospectively collected data and blood samples from patients with HIV who received the JYNNEOS vaccine, is small and included only 24 patients with HIV infection, with seven hospital workers who also received the vaccine and seven unvaccinated individuals as controls. “I am one of the control subjects of the study, and intradermal vaccination is not especially pleasant,” said Dr. Güerri-Fernandez. “It is a very innervated area, and the moment of introducing the liquid is uncomfortable. But it is perfectly bearable.”
Outpatient HIV-infected patients from the Infectious Diseases Unit of Hospital del Mar on antiretroviral therapy and with undetectable viral loads were grouped according to their CD4+ T-lymphocyte counts. Those with CD4+ T-lymphocyte counts ≤ 500/mm3 required at least one booster vaccine to exhibit efficient virus-specific T-lymphocyte responses. The magnitude of the T-cell response after this booster correlated directly with the CD4+ T-lymphocyte count of those vaccinated.
For Argentine infectious disease specialist Julián García, MD, clinical researcher at the Huésped Foundation in Buenos Aires, Argentina, who did not participate in the study, it is always productive to know that T-cell responses develop in patients with HIV infection, with CD4+ T-lymphocyte counts > and < 500/mm3, through an intradermal administration route.
Dr. García emphasized that the most novel aspect is that the JYNNEOS vaccine induces a specific T-cell response in patients with HIV infection that increases with higher CD4+ T-lymphocyte levels. However, he noted that the number of patients was less than 10 in most study groups, and the control group had only intradermal administration, which limits the interpretation of the results. “It will be necessary to verify this in studies with larger groups with control groups from all routes and with a correlate of protection.”
Dr. García referred to this latter point as a significant source of uncertainty. “The study is fundamentally based on the cellular response, but nowadays, there is no immune correlate of real-life protection.” He concluded that the study builds knowledge, which is essential for a vaccine that began to be used for mpox and the effectiveness of which is based on estimates.
Dr. Güerri-Fernandez and Dr. Garcia declared no relevant financial conflicts of interest.
This story was translated from the Medscape Spanish edition using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication. A version of this article appeared on Medscape.com.