Vaccination Administration Considerations for Specific Populations

Table 6. JYNNEOS and ACAM2000 Vaccination Administration Considerations for Specific Populations

¹The JYNNEOS vaccine may be administered subcutaneously using the standard regimen or by using the alternative regimen (intradermal route). The patient and provider may discuss whether to administer the vaccine intradermally or subcutaneously.

² Previous smallpox vaccination probably does provide some protection, but it may not necessarily be lifelong. During the 2003 mpox outbreak and during the current outbreak, several people who were infected with mpox had previously been vaccinated against smallpox decades prior. In response to the current outbreak, vaccines and other medical measures should be given to eligible people who were previously vaccinated against smallpox.

³ While there are no data for people who are pregnant, animal data do not show evidence of reproductive harm; pregnancy is not a contraindication to receiving JYNNEOS.

⁴ While there are no data for people who are breastfeeding, animal data do not show evidence of reproductive harm; breastfeeding is not a contraindication to receiving JYNNEOS. It is not known whether JYNNEOS is excreted in human milk. Data are not available to assess the impact of JYNNEOS on milk production or the safety of JYNNEOS in breastfed infants. However, because JYNNEOS vaccine is replication-deficient, it likely does not present a risk of transmission to breastfed infants and can be administered to women who are breastfeeding if vaccination is critical.

⁵ Presence of three or more of these major cardiac risk factors is a contraindication to vaccination with ACAM2000: hypertension, diabetes, hypercholesterolemia, heart disease at age ≤50 years in a first-degree relative, or smoking. Clinical studies have not detected an increased risk for myopericarditis in recipients of JYNNEOS. However, people with underlying heart disease (e.g., previous myocardial infarction, angina, congestive heart failure, cardiomyopathy, stroke or transient ischemic attack, or other heart conditions) or three or more major cardiac risk factors should be counseled about the theoretical risk for myopericarditis following vaccination with JYNNEOS given the uncertain etiology of myopericarditis associated with replication-competent smallpox vaccines such as ACAM2000.

⁶ Studies evaluating JYNNEOS in people with atopic dermatitis have demonstrated immunogenicity in eliciting a neutralizing antibody response. No concerning safety signals were revealed.

⁷ In the context of the current mpox outbreak, and while the supply of JYNNEOS vaccine is limited, the following are exceptions to the recommended two-dose series:

• A person who is diagnosed with mpox after their first dose of JYNNEOS is not recommended to receive the second dose at this time, because mpox infection likely confers additional immune protection.
• A person who would be eligible for vaccination but has been diagnosed with mpox during this outbreak, which started in the United States on May 17, 2022, is not recommended to be vaccinated at this time, because mpox infection likely confers immune protection.