Media Advisory
Wednesday, February 3, 2021
what
An experimental single dose intranasal influenza vaccine was safe and produced a durable immune response when tested in a Phase 1 study published in Journal of Clinical Investigation. The experimental vaccine, called Ad4-H5-VTN, is a replicating, recombinant adenovirus vaccine designed to stimulate antibodies against hemagglutinin, a protein found on the surface of influenza viruses that binds to human cells.
The experimental vaccine was developed by Emergent Biosolutions Inc., (Gaithersburg, Maryland). It was administered intranasally (28 study participants), as an oral capsule (10 participants) and through a tonsillar smear (25 participants) to healthy men and non-pregnant women aged 18 to 49 years.
Participants who received the vaccine intranasally or via tonsillar swab had significantly higher levels of neutralizing antibodies specific for H5 compared to the group that received the vaccine capsule orally. Participants who received the intranasal vaccine eliminated the viral DNA for two to four weeks, but the virus could be cultured for an average of just one day. Participants presented evidence of H5-specific CD4 + and CD8 + T cell responses. In addition, volunteers who received the intranasal vaccine had high levels of serum neutralizing antibodies at 26 weeks after vaccination, and that level remained unchanged for three to five years after a single intranasal dose of the vaccine. The duration of viral elimination correlated with a high magnitude of neutralizing antibody response at week 26. In addition, the intranasal vaccine induced a mucosal antibody response in the nose, mouth and rectum.
The study authors speculate that vector vaccines with competent replication may have advantages over other types of vaccines because they can express viral proteins at higher levels and for longer periods. In addition, this type of vaccine induces a mucosal immune response that is critical for limiting the transmission of viruses that infect mucosal tissues.
The vaccine platform can be highly adaptable for use against other viruses, including HIV and SARS-CoV-2, according to the authors.
Article
K Matsuda et al. A flu vaccine vectored by replication-competent adenovirus induces durable mucosal and systemic immunity. Journal of Clinical Investigation DOI: doi.org/10.1172/JCI140794.
Who
Mark Connors, MD, head of the HIV-specific Immunity Section at the NIAID Immunoregulation Laboratory and lead investigator for the Phase 1 study, is available for interviews.
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