Figure 1

Figure 2

The CDC supplies a recommended immunization schedule for children and adolescents 18 years of age and under (Figure 1).  This update will focus on the timing and spacing of vaccination in infants, so those persons aged 1-12 months.

Vaccinations such as varicella, MMR, and MMRV fall under the category of live attenuated viruses or bacteria. This means that the virus or bacterium is able to replicate inside of the body. Having any other antibody sources within the body could interfere with this replication process, and in consequence decrease the immune response, thus effectively producing “vaccine failure”. Inactivated vaccines, on the other hand, do not require replication to achieve an immune response because these vaccines contain no live viruses or bacteria. Therefore any other sources of antibody that may be present will not significantly influence the immune response in any way.

Sources of these antibodies can include any direct immune globin administrations or blood transfusions, but the major contribution of antibodies for neonates and infants is maternally derived. While passive immunity to certain conditions decreases faster than others, maternal antibody for MMR is not typically absent until the age of 1. It therefore takes approximately 12 months before the infant’s antibody titers decrease to a level suitable for live attenuated vaccination to produce the proper replication needed for an effective memory response.

Likewise, this same principle of antibody titer levels plays into the spacing of vaccinations. Antibody containing products cannot be given within two weeks of a live attenuated vaccine, and a live attenuated vaccine should not be given within four weeks of another live attenuated vaccine. This is due to the timeframe of the vaccine virus replication (Figure 2).

figure 1:http:// http://www.cdc.gov/vaccines/schedules/downloads/child/0-18yrs-child-combined-schedule.pdf

figure 2:http://www2a.cdc.gov/nip/isd/ycts/mod1/courses/genrec/10525.asp?student_id=

http://www.cdc.gov/vaccines/pubs/pinkbook/downloads/prinvac.pdf