Meeting report: 30th International Conference on Antiviral Research, in Atlanta, GA, USA

Vere Hodge, R Anthony

To evaluate vaccine efficacy in pregnant mice, C57BL/6 mice were administered vaccine (10 5 IFU) or placebo on day 0. Day 28, antibody levels were measured -as expected all the vaccinated group had high levels, the placebo group having none. On day 35, the mice were mated, then challenged with 10 6 focusforming units mouse-adapted Dakar ZIHV on day 41, at embryonic day 6 (E6). On day 48 (E13), various tissues were harvested and assayed for virus. The virus levels, in maternal spleen tissue taken from the vaccinated group, were undetectable in most mice, with a few having virus titres close to the LOD, whereas the placebo group had high levels, mostly between 4 and 7 log 10 IFU/g. In maternal brain tissues from the vaccinated group, virus levels were undetectable or at the LOD except for one mouse but, from the placebo group, ranged widely from low to high. In placenta, 9/30 had low levels in the vaccinated group, all high in the placebo group. In fetal head, again 9/30 had low levels in the vaccinated group, but a wide range from low to high in the placebo group. In all these tests, the differences between vaccinated and placebo groups were highly significant.