What time interval is needed between the administration of live attenuated vaccines?

Abstract

A mother consults you for her daughter’s 12-month-old measles–mumps–rubella (MMR) vaccination. The girl’s vaccination record reveals she had a Bacillus-Calmette-Guerin (BCG) vaccine 2 weeks prior because the family is planning to travel to India. You wonder what duration is needed between the administration of live attenuated vaccines to avoid diminishing vaccine responses. What time interval is needed between the administration of live attenuated vaccines to avoid interfering with the immune response to either vaccine? In February 2020, MEDLINE (1946 to present) was searched without any language limitations using the Ovid interface with the search terms detailed in the online supplementary data. ### Supplementary data [archdischild-2020-320091supp001.pdf] Our search identified 4592 studies. Of these, 16 fulfilled the inclusion criteria of studies in humans investigating interference on immunogenicity of two or more live attenuated vaccines administered simultaneously or consecutively (table 1; online supplementary results and table 1). References were hand-searched for additional publications, and no further relevant studies were found. One study was excluded because insufficient details were provided.1 View this table: Table 1 Findings of studies that have investigated the interference on vaccine immunogenicity of two or more different live attenuated vaccines administered consecutively Generally, simultaneous administration of vaccines on the same day is recommended to avoid missing opportunities for vaccination and to increase the probability that a child is …