Table 1.

Comparison between biological and pharmacological characteristics of JYNNEOS and ACAM2000 vaccines.

Characteristics	JYNNEOS Vaccine	ACAM2000 Vaccine
Generic name	Smallpox and monkeypox vaccine live non-replicating	Smallpox vaccinia, vaccine, live replicating
Brand name	JYNNEOS/Imamune/Imvanex, MVA Vaccinia Ankara	ACAM2000 Emergent Bio Solutions
Types of vaccine	Third-generation vaccine [14]	Second-generation vaccine [14]
Manufacturer, city and country	Bavarian Nordic, Hørsholm, Denmark	Gaithersburg, MD, USA and Sanofi Pasteur Biologics, LLC [9]
Vaccine production	Prepared using weakened live vaccinia virus, cannot cause smallpox or monkeypox. Produced from “strain-modified vaccinia Ankara-Bavarian Nordic (MVA-BN), an attenuated, non-replicating orthopoxvirus” [2]	The vaccine is made from a virus called vaccinia is a “pox”-type virus [7]
Replication-competent	A live-attenuated, non-replicating vaccine [8]	A live-attenuated replicating vaccine [8]
Produced from	“Strain-modified Vaccinia Ankara-Bavarian Nordic (MVA-BN), an attenuated, non-replicating orthopoxvirus” [7]	ACAM2000 is a “live vaccinia virus derived by plaque purification from a previously calf lymph-produced vaccine (Dryvax) and manufactured in Vero cells” [9]
Effective in age groups	Active immunization for the prevention of monkeypox disease in individuals less than 18 years, and 18 years of age and older [15]	Not effective in infants mainly aged <1 year, although vaccination is contraindicated [16]
FDA approval	FDA granted an emergency use authorization (EUA) for the emergency use of JYNNEOS/interim authorized, on 9 August 2022 [7], and a supplementary letter was issued on 2 September 2022	Interim authorized 28 June 2022, for people aged 1 year and older for monkeypox prophylaxis, CDC, ACAM2000 vaccine [17]
Dose(s)	Age <18 years: subcutaneous injection, 2 doses (0.5 mL each) 4 weeks (28 days) apart. Age ≥18 years: intradermal injection, two doses (0.1 mL each) 4 weeks (28 days) apart [15]	A single dose of 0.0025 mL droplet of reconstituted vaccine [17]
Booster shots	“Booster dose is recommended every two years for people with high-virulent orthopoxvirus, and every ten years for those in contact with low-virulent strains” [8,16]	High risk of exposure, researchers working in laboratories handling “variola virus, and monkeypox virus” should receive a booster dose every three years [16]
Route of administration	Subcutaneous injection [15]	Need a trained person, percutaneous route (scarification), prick the skin several times with a droplet of the vaccine. ACAM2000 cannot be given through subcutaneous, intradermal, intramuscular or intravenous routes [17]
Vaccination cost	The complete vaccination cost per person is about USD 115 [18]	The complete vaccination cost per person is about USD 139 [18].
Storage	Stored at −15 °C to −25 °C, once thawed the vaccine may be kept at +2 °C to +8 °C for 8 weeks [15]	Stored at −15 °C to −25 °C, shipment at −10 °C. After reconstitution use within 6–8 h at room temperature 20–25 °C. Reconstituted vaccine stored at 2–8 °C no longer than 30 days [17]
Mechanism of action	Produces “humoral and cellular immune responses to orthopoxviruses, neutralizing antibody for the prevention of smallpox and monkeypox” [15]	ACAM2000 vaccine stimulates the immune system to develop antibodies and cells in the blood to fight against infection [10]