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No difference found between intradermal and intramuscular influenza A vaccine
There was no difference in immune response between intramuscular and intradermal delivery of the subvirion inactivated influenza A virus subtype H5N1 vaccine, according to recent data.
“Vaccination via the intradermal route is based on the principle that the skin is rich in efficient antigen-presenting cells and in blood and lymphatic vessels for circulation of immune responses,” the researchers wrote. “Studies of vaccines for such diseases as hepatitis B virus infection and rabies have demonstrated that intradermal delivery using the Mantoux technique can be an effective alternative route for vaccination that uses smaller amounts of antigen.”
Because no previous studies have evaluated the differences between intramuscular and intradermal delivery of the lower vaccine dose, researchers from Baylor College of Medicine compared the two delivery methods among healthy adults. The study included 227 adults aged 18 to 49 years who were randomly assigned to two doses, 1 month apart, of a subvirion inactivated influenza A virus subtype H5N1 vaccine that contained 38.7mcg of H5N1 hemagglutinin, either intramuscularly or intradermally.
Within 1 month of the first vaccination, the geometric mean titer of serum hemagglutination inhibition and neutralizing antibodies were similar between the two groups and were low. After two doses of vaccine, the geometric mean titer levels were higher in both groups. In the intradermal group, injection site reactions were more common.
“Future investigations of intradermal vaccination with this novel influenza virus antigen (H5) should include adjuvants and a lower antigen content and comparison of intradermal administration via an intradermal delivery system,” the researchers wrote. “In addition, future investigations may include evaluation of other HA antigens, such as H7 or H9, which may not be as poorly immunogenic as the H5 antigen.”
Disclosure: The researchers report receiving research support from Protein Sciences, GlaxoSmithKline and Novartis Vaccines and Diagnostics.