Building a safer CMV vector

Vaccines Vaccine vectors based on cytomegalovirus (CMV) show strong T cell induction and protection against a multitude of pathogens. However, such vaccines may not be safe for people who are immunodeficient or immunosuppressed. Marshall et al. genetically modified rhesus CMV to allow engagement of host intrinsic immunity. The modified ΔRh110 vector did not spread once administered to nonhuman primates but still induced robust T cell immunity. Hansen et al. showed in a simian immunodeficiency virus challenge model that the ΔRh110 vector provided durable protection that was comparable to the parental vector. Mutations in the human CMV vector could thus yield a potent but restrained CMV for human vaccination. Sci. Transl. Med. 11 , eaaw2603, eaaw2607 (2019).