Results of a phase 1 study demonstrated that vaccination against influenza using a dissolvable microneedle patch is not only well tolerated, but also produces “robust antibody responses.”

• Placebo-controlled phase 1 study assessed the safety, immunogenicity, and tolerability of dissolvable microneedle patches for delivery of the influenza vaccine
• 100 patients were randomized “(1:1:1:1) to four groups and received a single dose of inactivated influenza vaccine (fluvirin: 18 μg of haemagglutinin per H1N1 vaccine strain, 17 μg of haemagglutinin per H3N2 vaccine strain, and 15 μg of haemagglutinin per B vaccine strain) (1) by microneedle patch or (2) by intramuscular injection, or received (3) placebo by microneedle patch, all administered by an unmasked health-care worker; or received a single dose of (4) inactivated influenza vaccine by microneedle patch self-administered by study participants”
• Partly blinded study: patients were not masked to vaccine route of administration
• Primary safety endpoints: occurrence of serious adverse events within 180 days of product administration, grade 3 adverse events (solicited or unsolicited) that occurred within 28 days of administration, reactogenicity (systemic and injection site) at product administration through day 7
• Secondary safety endpoints: chronic illness within 180 days of administration (new-onset only), unsolicited adverse events occurring within 28 days of administration
• All outcomes utilized an intention-to-treat analysis

• Zero treatment-related serious adverse events were reported
• Zero unsolicited grade 3 or higher treatment-related adverse events were reported
• Zero new-onset chronic illnesses were reported
• “Among vaccinated groups (vaccine via health-care worker administered microneedle patch or intramuscular injection, or self-administered microneedle patch), overall incidence of solicited adverse events (n=89 vs n=73 vs n=73) and unsolicited adverse events (n=18 vs n=12 vs n=14) were similar”
• Reactogenicity after vaccination via intramuscular injection: 60% of patients reported tenderness (15/25; 95% CI: 39, 79) and 44% of patients experienced pain (11/25; 95% CI: 24, 65)
• Reactogenicity after vaccination via microneedle patch application: 66% of patients reported tenderness (33/50; 95% CI: 51, 79), 40% of patients experienced erythema (20/50; 95% CI: 26, 55), and 82% of patients experienced pruritus (41/50; 95% CI: 69, 91)
• The geometric mean titres were similar at day 28 between the microneedle patch administered by a health-care worker versus the intramuscular route for the H1N1 strain (1197 [95% CI 855–1675] vs 997 [703–1415]; p=0·5), the H3N2 strain (287 [192–430] vs 223 [160–312]; p=0·4), and the B strain (126 [86–184] vs 94 [73–122]; p=0·06)
• Geometric mean titers reported for patients who self-administered the microneedle patch were also similar (P>0.05)
• Seroconversion percentages: significantly higher in patients who received the microneedle patch vaccination vs patients who received placebo (P<0.0001) and similar to patients who received vaccination via intramuscular injection (P>0.01)