US military smallpox vaccination program: occupational impact of immunizations on aircrew in Air Mobility Command, US Air Force.

CONTEXT

President George W. Bush announced a national smallpox vaccination program (SVP) on December 13, 2002, for military personnel, civilian healthcare workers, and "first responders." The program was intended to protect these individuals against exposure to weaponized smallpox. The US Air Force (USAF) began implementation of the SVP on January 7, 2003.

OBJECTIVES

To determine if the SVP affected USAF personnel readiness, and, based on these results, to determine the overall safety of a large-scale SVP.

METHODS

A retrospective cohort study of duty-restriction rates measured by duties not to include flying (DNIFs) of C-17 aircrews in the USAF Air Mobility Command (AMC). Data from January 2002 to May 2002 (prevaccination) and January 2003 to May 2003 (vaccination) were compiled by month from three of the 11 AMC bases. Total DNIFs associated with or attributed to the smallpox vaccine were recorded. In addition, total 2003 DNIFs in 1662 study subjects (678 [40.8%] of whom received smallpox vaccination) were recorded and compared with total 2002 DNIFs in 1602 control subjects before SVP implementation. Differences in monthly DNIF rates were calculated using the one-tailed paired t test.

RESULTS

In the 678 subjects who received smallpox vaccination, 13 vaccine-related DNIFs (1.9%) occurred. Differences in DNIF rates were statistically significant (P<.05) during 2 months at one AMC base. However, the SVP did not increase overall DNIF rates in the SVP study period.

CONCLUSIONS

With DNIF status as a health marker, the SVP did not impose operational constraints or adversely affect aircrew preparedness in the USAF AMC. The authors suggest that a similar SVP with comparable screening measures would indicate the overall safety of the vaccine.