multiple doses, there are an almost infinite number of possible vaccine schedules that can be used. To scientifically evaluate the safety of different vaccine schedules, it is necessary to look at specific components of the schedule. Some such components are as follows:

Timing of Specific Vaccines

  • The age at which a specific vaccine is given, such as the age at the first dose of the hepatitis B vaccine.
  • The relative timing of different doses of the same vaccine, such as the number of months between the first and second doses of the 7-valent pneumococcal conjugate vaccine (PCV7).
  • The interaction between the timing of a specific vaccine and time-varying health events or health status, such as a vaccination given to a child taking a temporary or seasonal medication.

Relative Timing of Two or More Different Vaccines

  • The interaction among different vaccines given on the same day, such as the effect of giving the measles, mumps, and rubella (MMR) vaccine and varicella vaccines at the same health care visit or different health care visits.
  • The order in which different vaccines are given, such as whether measles vaccine is given a few months before or after the diphtheria-tetanus-pertussis (DTP) vaccine.

Summary Metrics of a Vaccine Schedule

  • The total number of vaccinations given to the child before a certain age, such as the 6th birthday.
  • The average age at which the vaccines were given.
  • The cumulative amount of immune-stimulating content present in all vaccines received.

In addition to specific components of the vaccine schedule, one can also try to compare complete vaccine schedules.

Comparison of Complete Vaccine Schedules

  • Whether or not the child has approximately followed the CDC-recommended vaccine schedule.
  • The comparative safety of a specific alternative vaccine schedule, such as Dr. Bob’s (Sears, 2007), versus the one recommended by CDC.


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