INFORMATION FOR ACCP MEMBERS: Monkeypox Vaccination/Treatment and Call for Clinician Input

August 19, 2022

Over 40,000 cases of monkeypox have been reported worldwide (CDC, data through 8/17/2022). In the US, all but two states have reported cases of monkeypox and cases have been reported in all age groups. More than 25% of all US cases have been reported in New York City.

The only FDA-licensed monkeypox virus vaccine is JYNNEOS (modified Vaccinia Ankara (MVA) vaccine), manufactured by Bavarian Nordic. It was approved in 2019 for the prevention of smallpox and monkeypox in adults. Over 630,000 doses from the national stockpile have been distributed to state public health departments, but there is now a very limited supply and the manufacturer is currently not expected to release more stock until the end of October. The CDC recommends administration within 4 days of exposure to prevent disease or within 14 days of exposure to reduce symptoms. Since the vaccine is made from a modified live virus, it isn't able to replicate in the body. While it is normally given subcutaneously in a dose of 0.5 mL in a 2-dose series separated by 28 days, under the EUA the CDC has approved an alternative dose-sparing regimen of intradermal administration with 0.1 mL dose using the same 2-dose series. Doses are given with a standard intradermal needle using the standard administration procedure. It’s stored and shipped frozen and must be used within 12 hours after being thawed.

In the current setting of a limited vaccine supply, the CDC has been limiting vaccine availability to the high-risk contacts of monkeypox patients and the healthcare workers treating them.

The current categories are:

• people who have been identified by public health officials as a contact of someone with monkeypox;
• people who are aware that one of their sexual partners in the past two weeks has been diagnosed with monkeypox;
• people who had multiple sexual partners in the past two weeks in an area with known monkeypox; and
• people whose jobs may expose them to orthopoxviruses, such as those performing testing or who handle cultures or animals with one of these
• viruses and some designated healthcare or public health workers
• designated healthcare or public health workers

The efficacy of the vaccine in monkeypox hasn’t been confirmed in controlled studies, but the CDC has data suggesting an 85% protection (seroconversion). Breakthrough cases have already been reported in the US.

ACAM2000, the smallpox vaccine, is unmodified vaccinia virus Ankara. It isn’t approved for monkeypox, but may be administered under an Expanded Access Investigational New Drug (EA-IND) protocol. Institutions that want to immunize patients with ACAM2000 need to undergo the full process for obtaining permission to implement an IND protocol. As the unmodified virus, it can replicate (aka a live virus vaccine) and has the standard contraindications for immunocompromised, immunosuppressed, and pregnant patients, and has been linked to cases of myocarditis. It hasn’t been studied in children. It’s given intradermally via a vaccinator with a bifurcated needle and creates a pustule that sheds live virus, posing a risk for infecting others, for 1-2 weeks until it heals. For more information, see https://www.cdc.gov/poxvirus/monkeypox/considerations-for-monkeypox-vaccination.html

The CDC has also provided guidance for use of tecovirimat (TPOXX) under an EA-IND in patients with monkeypox. Like the ACAM2000 vaccine, tecovirimat has FDA approval only for the treatment of smallpox and is maintained in the national stockpile. Institutions that want to treat patients with TPOXX must undergo the full process for obtaining permission to implement an IND protocol. Supplies have also been distributed to state public health departments. It is given orally (as capsules or the powder from the capsule mixed in liquid) or IV (a 6-hour infusion) for 14 days. Dosing is weight-based and includes infants and children. It should not be given to patients with severe renal impairment. Adverse effects appear to be relatively mild, with flu-like symptoms and injection site reactions (see https://www.cdc.gov/poxvirus/monkeypox/clinicians/obtaining-tecovirimat.html).

Call for Clinician Input

ACCP members are asked to share experiences, emerging best practices and resources that may provide important information and insights for those caring for patients with monkeypox infection or exposure. For more information, click HERE.