Vaccine effective against China’s avian influenza A (H7N9)

by Michael Woodhead
A vaccine has been shown to be effective in humans against the new avian-origin influenza A (H7N9) virus that has already caused 137 cases and 45 deaths in China.

Australian and US researchers developed an A/Anhui/1/13 (H7N9) viruslike particle (VLP) vaccine that combines the HA and neuraminidase (NA) of A/Anhui/1/13 with the matrix 1 protein (M1) of A/Indonesia/5/05.

Writing in the NEJM they say avian influenza viruses have acquired mutations that could facilitate infection in mammals, which could pose a pandemic threat if the viruses become readily transmissible in humans. They have previously shown the efficacy of the vaccine in mice, and in a new study they have demonstrated the efficacy of the VLP vaccine in humans.

In a randomized, placebo-controlled clinical trial of the vaccine in 284 Australian adults two identical doses were given 21 days apart.

When followed up after a month, a strong immune response was seen in 81% of partcipants receiving 5 μg of vaccine with adjuvant. Significant increases in N9 neuraminidase-inhibiting antibodies occurred in 97.2% of recipients of vaccine with 60 units of adjuvant.

The VLP vaccine with adjuvant was associated with increased local and systemic reactions, but few of the reactions were severe, and no body temperatures exceeded 38.5°C.

The researchers from Novavax say the vaccine appears to be a good candidate for prevention of a pandemic  avian-origin influenza A (H7N9).

See the full report in: NEJM DOI: 10.1056/NEJMc1313186