Objective:
To establish whether multiple vaccinations in DSTL Porton Down staff were associated with an excess of sickness absence and possible adverse health effects.
Methods:
A retrospective cohort study of employees at DSTL Porton Down (a U.K. Ministry of Defence research establishment), using records covering a 2 - 38 year period and held in the Occupational Health and Personnel Departments. The study involved 118 civilian staff at DSTL Porton Down who had been vaccinated against four or more diseases during their adult lives. The study included 89% of multi-vaccinated staff. Most individuals received five different vaccines, while seven received ten or more. Only very rarely was more than one vaccine given on the same day to any individual. A matched contemporary control group of 212 employees was used for comparison. All absence from work attributed to sickness during the period the subjects were employed at DSTL Porton Down was recorded.
Results:
Mean annual sick leave was 3.4 days for the multi-vaccinated group and 4.3 days for the controls (medians 1.4 and 2.1 days respectively). This compares to a mean of 7 days for all DSTL employees during a single 12 month period (April 1998 to March 1999).
Conclusions:
No excess sickness absence occurred amongst DSTL staff vaccinated against four or more diseases, compared to a matched control group. Sickness absence rates did not increase as a function of the number of diseases vaccinated against or the length of employment and thus the total number of vaccinations.