To the Editor: The US government recently announced
a program to offer smallpox immunization to hospital health care workers (HCWs).
The vaccine contains live vaccinia virus and carries a risk of significant
adverse events for vaccinees and their close contacts. From experience in
the 1960s, for every 100 000 primary vaccinees, there would be an expected
2 to 6 transmissions of virus to unvaccinated contacts, with 1 to 2 cases
of eczema vaccinatum.1 Individuals at high
risk of serious complications from contact vaccinia (CV) include immunocompromised
contacts, those with chronic dermatologic conditions, and children younger
than 5 years.1 In the past, most transmission
occurred in the home setting and rarely as a result of hospital-related contact.
However, because hospital transmission to patients has been documented,1 vaccinating HCWs may expose patients to undue risk.
The number of patients currently at increased risk in hospitals is unknown,
but is certainly higher than in the 1960s.
Smith PF, Chang H, Sepkowitz KA. Inpatients at Risk of Contact Vaccinia From Immunized Health Care Workers. JAMA. 2003;289(12):1512–1513. doi:10.1001/jama.289.12.1512-a
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