The broad influenza vaccine candidate BPL-1357 was tested in people for the first time in a phase 1 trial of 45 healthy adults. Intramuscular dosing raised some antibody responses to influenza subtypes, whereas the nasal route yielded weaker responses. Seven months of safety follow-up provide early evidence, but the study was not designed to measure protection against infection.
BPL-1357 is a vaccine candidate made from four influenza viruses inactivated with beta-propiolactone. In the peer-reviewed phase 1 trial, 76 people were screened and 45 healthy adults were randomly assigned to three groups. Fifteen each received intramuscular vaccine, intranasal vaccine or placebo. The double-blind, double-dummy design concealed group assignment despite the different routes of administration.[1]
The candidate contains H1N9, H3N8, H5N1 and H7N3, exposing the immune system to several viral components rather than one surface protein. Intramuscular dosing increased serum binding antibodies against H3, H5 and H7 and some neutralizing responses. Serum and nasal antibody results after intranasal dosing were more limited. The investigators also measured T-cell responses.[1]
Over seven months of follow-up, adverse effects were predominantly mild or moderate. Pain where the needle entered occurred more often in the muscle-injection group. Investigators judged one severe, grade 3 fever after nasal vaccination potentially linked to the candidate. No influenza cases were detected, but this was not an efficacy trial measuring protection from infection. A small healthy-adult sample cannot establish rare adverse effects or outcomes in other age groups.[1]
