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

Vere Hodge, R Anthony

The 10-del ZIKA vaccine was administered subcutaneously (sc). Mice were administered vaccine or wt virus (10 4 plaque-forming units (PFU)) on day 0. Viraemia and weight were measured on days 2, 3 and 4. On day 28, the neutralising titre was measured and mice challenged with wt virus (10 6 PFU). Subsequent viraemia and weight were followed. As expected, there were high levels of viraemia following infection with wt virus, the viral titres being about 5, 6 and 5 log 10 PFU/ ml on days 2, 3 and 4, respectively. In contrast, the corresponding titres for the vaccine were about 2, 2.5 and 3, respectively. Also, there was no disease or weight loss in the vaccinated mice. The vaccinated mice were fully protected from detectable viraemia after the wt virus challenge (10 6 PFU). Antibody titres, at 28 days after vaccination, were nearly 4 log 10 in both groups and the titres were no higher at 28 days after virus challenge. Such effective antibody titres are sometimes referred to as 'sterilising antibodies', there being no detectable viraemia and not even a rise in antibody levels after a virus challenge.