Media advice
Wednesday, February 3, 2021
What
A single dose experimental intranasal influenza vaccine was safe and produced a durable immune response when tested in a phase 1 study published in the Journal of Clinical Investigation. The research vaccine, called Ad4-H5-VTN, is a recombinant, replicating adenovirus vaccine designed to detect antibodies to hemagglutinin, a protein found on the surface of influenza viruses that attaches to human cells.
The research vaccine has been developed by Emergent Biosolutions Inc., (Gaithersburg, Maryland). It was administered intranasally (28 study participants), as an oral capsule (10 participants), and by tonsillar smear (25 participants) to healthy men and non-pregnant women aged 18 to 49 years.
The participants who received the vaccine intranasally or via a tonsillar smear showed significantly higher H5-specific neutralizing antibody levels compared to the group who received the vaccine capsule orally. The participants who received the intranasal vaccine shed viral DNA for two to four weeks, but the virus could be grown for a median of only one day. Participants had 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 this level was unchanged for three to five years after a single intranasal dose of the vaccine. The duration of viral shedding correlated with a high rate 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 replication-competent vector vaccines may have advantages over other types of vaccines in that they can express viral proteins at higher levels and for longer durations. In addition, this type of vaccine elicits a mucosal immune response that is crucial for limiting the transmission of viruses that infect mucosal tissues.
The vaccine platform could be highly adaptable for use against other viruses, including HIV and SARS-CoV-2, according to the authors.
Article
K Matsuda et al. A replication competent adenovirus-vectored influenza vaccine induces durable systemic and mucosal immunity. Journal of Clinical Investigation DOI: doi.org/10.1172/JCI140794.
WHO
Mark Connors, MD, chief of the HIV-specific immunity division in the NIAID’s immunoregulation lab and principal investigator for the phase 1 study, is available for interviews.
NIAID conducts and supports research – at NIH, in the United States and worldwide – to study the causes of infectious and immune-mediated diseases and to develop better tools to prevent, diagnose and treat these diseases. News releases, fact sheets and other NIAID-related material are available on the NIAID website.
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