Third-Generation Smallpox Vaccine Appears Safe, Effective in HIV and Atopic Dermatitis Patients
A third-generation smallpox vaccine currently under fast-track approval by the US Food and Drug Administration (FDA) is safe and effective in people with human immunodeficiency virus (HIV) and atopic dermatitis (AD), research suggests.
Conventional smallpox vaccines are contraindicated in persons with immunodeficiency, those with certain skin conditions, such as eczema or AD, and pregnant women due to serious and potentially fatal complications.
"The problem with the traditional vaccines is that they have a safety profile that may have been adequate during the smallpox eradication phase, but it is not a safety profile that you would expect from a modern vaccine in a prevention scenario," said Jens Vollmar, MD, medical director at Bavarian Nordic GmbH. There is currently not an approved alternative to protect these populations from infection from smallpox exposure.
Dr. Vollmar presented a summary of clinical trials here at the International Conference on Emerging Infectious Diseases (ICEID) in which more than 150 subjects with contraindications for conventional smallpox vaccines (including HIV and AD) and 350 healthy subjects received 2 to 3 vaccinations with either the third-generation vaccine (MVA-BN) or modified vaccinia ankara (MVA)based recombinant vaccines. Subjects were closely monitored for adverse reactions, and humoral (PRNT/ELISA) and cellular (ICS/ELISPOT) immune response monitoring was used to determine immunogenicity.
Results showed that MVA-BN was well-tolerated in subjects with HIV or AD, with no reported serious or unexpected adverse reactions. Mild to moderate systemic reactions and/or reactions at the injection site observed among HIV and AD subjects were comparable to those in healthy subjects who received 1 x 108 TCID.
Among HIV-infected subjects, MVA-based vaccines were safely administered in doses up to 5x108 TCID50. After each vaccination with MVA-BN, median CD4+ T-cell counts in subjects increased by approximately 80 cells/µL, then trended back toward baseline.
Among AD subjects, no cases of eczema vaccinatum were observed, and no cases of myo-/pericarditis were reported during prospective monitoring.
Across healthy, HIV, and AD subjects, vaccination induced strong antibody and T-cell responses. More than 80% of vaccinia-naive subjects seroconverted within 2 weeks of the first vaccination, which increased to 100% seroconversion after 4 weeks.
"This vaccine may offer a much improved safety profile for healthy individuals as well as in those which have contraindications for the traditional vaccines," concluded Dr. Vollmar.
The clinical implications with regard to the general population are clear. "If this new vaccine overcomes the issue of immunodeficiency, it could become the new standard in vaccination for smallpox," said Alvaro Lopez, MD, from Infectious Disease Consultants in Atlanta, Georgia, who was not involved in the study.
Dr. Vollmar is employed by Bavarian Nordic, the maker of MVA-BN (IMVAMUNE). Clinical trials were partially funded by the National Institute of Allergy and Infectious Diseases.
Conventional smallpox vaccines are contraindicated in persons with immunodeficiency, those with certain skin conditions, such as eczema or AD, and pregnant women due to serious and potentially fatal complications.
"The problem with the traditional vaccines is that they have a safety profile that may have been adequate during the smallpox eradication phase, but it is not a safety profile that you would expect from a modern vaccine in a prevention scenario," said Jens Vollmar, MD, medical director at Bavarian Nordic GmbH. There is currently not an approved alternative to protect these populations from infection from smallpox exposure.
Dr. Vollmar presented a summary of clinical trials here at the International Conference on Emerging Infectious Diseases (ICEID) in which more than 150 subjects with contraindications for conventional smallpox vaccines (including HIV and AD) and 350 healthy subjects received 2 to 3 vaccinations with either the third-generation vaccine (MVA-BN) or modified vaccinia ankara (MVA)based recombinant vaccines. Subjects were closely monitored for adverse reactions, and humoral (PRNT/ELISA) and cellular (ICS/ELISPOT) immune response monitoring was used to determine immunogenicity.
Results showed that MVA-BN was well-tolerated in subjects with HIV or AD, with no reported serious or unexpected adverse reactions. Mild to moderate systemic reactions and/or reactions at the injection site observed among HIV and AD subjects were comparable to those in healthy subjects who received 1 x 108 TCID.
Among HIV-infected subjects, MVA-based vaccines were safely administered in doses up to 5x108 TCID50. After each vaccination with MVA-BN, median CD4+ T-cell counts in subjects increased by approximately 80 cells/µL, then trended back toward baseline.
Among AD subjects, no cases of eczema vaccinatum were observed, and no cases of myo-/pericarditis were reported during prospective monitoring.
Across healthy, HIV, and AD subjects, vaccination induced strong antibody and T-cell responses. More than 80% of vaccinia-naive subjects seroconverted within 2 weeks of the first vaccination, which increased to 100% seroconversion after 4 weeks.
"This vaccine may offer a much improved safety profile for healthy individuals as well as in those which have contraindications for the traditional vaccines," concluded Dr. Vollmar.
The clinical implications with regard to the general population are clear. "If this new vaccine overcomes the issue of immunodeficiency, it could become the new standard in vaccination for smallpox," said Alvaro Lopez, MD, from Infectious Disease Consultants in Atlanta, Georgia, who was not involved in the study.
Dr. Vollmar is employed by Bavarian Nordic, the maker of MVA-BN (IMVAMUNE). Clinical trials were partially funded by the National Institute of Allergy and Infectious Diseases.
posted by Smile Community @ 6:43 PM
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