Poxviruses Medication

Updated: Nov 08, 2019
  • Author: John D Shanley, MD, MPH; Chief Editor: Michael Stuart Bronze, MD  more...
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Medication Summary

Numerous nucleoside and nucleotide agents have demonstrated potent antiviral activity against poxvirus infection in vitro and in animal models. Cidofovir has been used successfully to treat extensive molluscum contagiosum and orf in patients with AIDS. [8, 10, 9] Vaccination remains a key defense for patients at high risk of infection.


Vaccines, Live, Viral

Class Summary

Vaccinia vaccine promotes active immunity against the smallpox virus by inducing specific antibodies. Currently available stocks of vaccinia vaccine were derived from the vaccinia strain maintained at the New York Board of Health. Wyeth Laboratories manufactured the last batches of the vaccine (Dryvax) in the early 1980s. These batches were made by using the calf lymph method, and they were lyophilized but are no longer available.

Several attenuated vaccinia vaccine candidates are undergoing investigation, with ACAM2000 receiving FDA approval as a replacement for Dryvax. Another vaccine (smallpox [vaccinia] and monkeypox vaccine, live, nonreplicating [Jynneos]) has also been approved by the FDA for immunization of adults at high risk for smallpox or monkeypox infection.

New cell-derived lots of vaccinia appear to have adverse effect profiles similar to those of the older calf lymph–derived lots.

Smallpox (vaccinia) vaccine, live (ACAM2000)

This agent is made from vaccinia, which is related to, but different from, the virus that causes smallpox. It contains live vaccinia virus and works by causing a mild infection that stimulates an immune response that effectively protects against smallpox without actually causing disease.

The vaccine contains live vaccinia virus but does not contain variola virus, the virus that causes smallpox. Vaccinia is a member of the Orthopoxvirus genus, which includes smallpox (variola), cowpox, monkeypox, gerbilpox, camelpox, and others. Following inoculation, the vaccine induces an immune reaction that protects against smallpox.

ACAM2000 is derived from Dryvax, which is the only other smallpox vaccine licensed by the FDA. Dryvax, which was approved in 1931, is now in limited supply because it is no longer being manufactured. The US military resumed vaccination of at-risk personnel in 1999 after concluding that the disease posed a potential bioterrorism threat.

Smallpox (vaccinia) and monkeypox vaccine, live, nonreplicating (Jynneos)

Vaccine is derived from a vaccinia virus, a virus that is closely related to, but less harmful than, variola or monkeypox viruses and can protect against both of these diseases. It is indicated for prevention of smallpox and monkeypox disease in adults who are at high risk for smallpox or monkeypox infection. It is administered as a 2-dose series administered 4 weeks apart.