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ACAM2000 is a smallpox vaccine and an mpox vaccine manufactured by Emergent Biosolutions. It provides protection against smallpox for people determined to be at high risk for smallpox infection. ACAM2000 is a live replicating vaccinia virus vaccine.

Medical uses

ACAM2000 is indicated for active immunization against smallpox disease for individuals determined to be at high risk for smallpox infection. It is also indicated for the active prevention of mpox disease in individuals determined to be at high risk for mpox infection.

History

ACAM2000 is a vaccine developed by Acambis, which was acquired by Sanofi Pasteur in 2008, before selling the smallpox vaccine to Emergent Biosolutions in 2017. Six strains of vaccinia were isolated from 3,000 doses of Dryvax and found to exhibit significant variation in virulence. The strain with the most similar virulence to the overall Dryvax mixture was selected and grown in MRC-5 cells to make the ACAM1000 vaccine. After a successful Phase I trial of ACAM1000, the virus was passaged three times in Vero cells to develop ACAM2000, which entered mass production at Baxter. The United States ordered over 200 million doses of ACAM2000 in 1999–2001 for its stockpile, and production is ongoing to replace expired vaccine.

Emergent Biosolutions developed ACAM2000 under a contract with the US Centers for Disease Control and Prevention (CDC).

The US Food and Drug Administration (FDA) approved ACAM2000 in August 2007. By February 2008, it replaced Dryvax for all smallpox vaccinations.

As of 2010, there were over 200 million doses manufactured for the US Strategic National Stockpile.

According to the US FDA, "The approval and availability of this second-generation smallpox vaccine in the Strategic National Stockpile (SNS) enhances the emergency preparedness of the United States against the use of smallpox as a dangerous biological weapon."

In August 2024, ACAM2000 was approved for mpox prevention in the United States.

Administration of ACAM2000

The ACAM2000 vaccine is produced from the vaccinia virus, which is sufficiently closely related to smallpox to provide immunity, but the ACAM2000 vaccine cannot cause smallpox because it does not contain the smallpox virus. Other vaccines containing live viruses include measles, mumps, rubella, polio and chickenpox.

The vaccine is administered using a bifurcated stainless steel needle. The needle is dipped into the vaccine solution and used to prick the skin several times in the upper arm. The vaccinia virus will begin to grow at the injection site. It will cause a localized infection, with a red itchy sore produced at the vaccination site within three to four days. If the infection occurs, that is an indication that the vaccine was successful. Ultimately, the sore turns into a blister and then dries up. A scab forms and then falls off in the third week, leaving a small scar behind.

Risks

Administration of ACAM2000 poses risks and may cause side effects. Most people who have taken the vaccine only report mild reactions. Reactions may include a sore arm, fever, and body aches. Some people may have more serious side effects, including effects that may be life-threatening.

According to the FDA-approved prescribing information leaflet, "Common adverse events include inoculation site signs and symptoms, lymphadenitis, and constitutional symptoms, such as malaise, fatigue, fever, myalgia, and headache." These reactions are less frequent in people being revaccinated than those receiving the vaccine for the first time.

No known contraindications exist to receiving the vaccine in case of an outbreak emergency. Furthermore, it is recommended that the vaccine should be given to pregnant women who have been exposed to smallpox. "Because the risk of maternal serious illness or death, prematurity, miscarriage, or stillbirth from a smallpox infection are greater than the risk of the vaccination, smallpox vaccine is recommended and should be offered to pregnant women in case of an outbreak emergency."

References

1. ^ "ACAM2000 smallpox vaccine (live vaccinia virus) vial with diluent (153108)". Therapeutic Goods Administration (TGA). 26 May 2022. Retrieved 2 October 2024.
2. ^ "ACAM2000 (smallpox- vaccinia vaccine, live injection, powder, lyophilized, for solution". DailyMed. U.S. National Library of Medicine. 21 March 2018. Retrieved 10 January 2023.
3. "Regulatory Decision Summary for ACAM2000". Drug and Health Products Portal. 5 December 2023. Archived from the original on 2 April 2024. Retrieved 2 April 2024.
4. ^ "ACAM2000". U.S. Food and Drug Administration (FDA). 29 August 2024. Retrieved 1 September 2024.
5. ^ "FDA Roundup: August 30, 2024". U.S. Food and Drug Administration (FDA) (Press release). 30 August 2024. Retrieved 1 September 2024.
6. http://cfile204.uf.daum.net/attach/99D1CC495CC112781A6A94. {{cite web}}: Missing or empty |title= (help)
7. Monath TP, Caldwell JR, Mundt W, Fusco J, Johnson CS, Buller M, et al. (October 2004). "ACAM2000 clonal Vero cell culture vaccinia virus (New York City Board of Health strain)--a second-generation smallpox vaccine for biological defense". International Journal of Infectious Diseases. 8 (Suppl 2): S31–S44. doi:10.1016/j.ijid.2004.09.002. PMC 7110559. PMID 15491873.
8. Nalca A, Zumbrun EE (May 2010). "ACAM2000: the new smallpox vaccine for United States Strategic National Stockpile". Drug Design, Development and Therapy. 4: 71–79. doi:10.2147/dddt.s3687. PMC 2880337. PMID 20531961.
9. "About ACAM2000" (PDF). Emergent Biosolutions. Archived from the original (PDF) on 14 August 2018. Retrieved 8 September 2018.
10. ^ Nalca A, Zumbrun EE (May 2010). "ACAM2000: the new smallpox vaccine for United States Strategic National Stockpile". Drug Design, Development and Therapy. 4: 71–79. doi:10.2147/dddt.s3687. PMC 2880337. PMID 20531961.
11. ^ "ACAM2000 (Smallpox Vaccine) Questions and Answers". U.S. Food and Drug Administration (FDA). Retrieved 8 September 2018. This article incorporates text from this source, which is in the public domain.
12. "Emergent Biosolutions' ACAM2000, (Smallpox and Mpox (Vaccinia) Vaccine, Live) Receives U.S. FDA Approval for Mpox Indication; Public Health Mpox Outbreak Continues Across Africa & Other Regions" (Press release). Emergent Biosolutions. 29 August 2024. Retrieved 1 September 2024 – via GlobeNewswire.
13. "Smallpox Vaccine Basics". U.S. Centers for Disease Control and Prevention (CDC). 13 July 2017. Retrieved 8 September 2018.
14. "Smallpox Vaccine Safety". U.S. Centers for Disease Control and Prevention (CDC). 13 July 2017. Retrieved 8 September 2018.
15. "Smallpox vaccine Use During Pregnancy". Drugs.com. Retrieved 8 September 2018.

External links

• "Medication Guide Smallpox (Vaccinia) Vaccine, Live ACAM2000" (PDF). U.S. Food and Drug Administration (FDA).

• Medicine
• Viruses

• Healthcare in the United States
• History of immunology
• Infectious diseases
• Smallpox
• Smallpox vaccines
• Vaccines