Until recently, the Zika virus was not a priority since it affected relatively few people and the cost of creating a vaccine was estimated at EUR 149-468 million. But the spread of Zika in the Americas and discovery of a link with reduced head size and brain damage in babies of women infected while pregnant changed that.
One challenge is to ensure that any vaccine – which would typically include an agent similar to the virus – doesn’t harm foetuses. Valneva is making a vaccine with a disease-causing agent that has been killed but nonetheless stimulates the immune system to protect against the virus. So even if the agent crosses the placenta, it doesn’t infect the baby.
