We frequently see patients, such as immigrants, who do not have records of past vaccination or who insist they or their children are up to date. Should we accept their undocumented vaccination history?

Vaccination providers frequently encounter people who do not have adequate documentation of vaccinations. Providers should only accept written, dated records as evidence of vaccination. CDC recommends that, with the exception of influenza and pneumococcal polysaccharide vaccines, self-reported doses of vaccine without written documentation should generally not be accepted. An attempt to locate missing records should be made whenever possible by contacting previous healthcare providers, reviewing state or local immunization information systems, and searching for a personally held record. However, if records cannot be located or will definitely not be available anywhere because of the patient’s circumstances, people without adequate documentation should be considered susceptible and should be started on the age-appropriate vaccination schedule. Serologic testing for immunity is an alternative to vaccination for certain antigens (e.g., measles, rubella, or hepatitis A).

In general, although it is not ideal, receiving extra doses of vaccine poses no medical problem. Receiving excessive doses of tetanus toxoid (DTaP, DT, Tdap, or Td) can increase the risk of a local adverse reaction, however. For details, consult the ACIP’s “Best Practice Guidelines for Immunization” chapter titled Timing and Spacing of Immunobiologics, available at www.cdc.gov/vaccines/hcp/imz-best-practices/timing-spacing-immunobiologics.html.