"Viruses for some vaccines are grown in laboratories using animal cell cultures. This is because viruses will only grow in human or animal cells. In the UK schedule this applies to these vaccines: *The polio part of the 6-in-1 vaccine (Infanrix Hexa), the pre-school booster vaccines (Repevax, Infanrix IPV and Boostrix-IPV) and the teenage booster vaccine (Revaxis) *The Rotavirus vaccine (Rotarix) * One of the Inactivated flu vaccines (QIVc) Viruses for these vaccines are grown on Vero cells. This is a cell line started in the 1960s using kidney cells from an African green monkey."