New Anthrax Vaccine Added to Arsenal of Defense Against Bioterrorism

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A Brief History of Anthrax Attacks in the U.S.

Shortly after the attacks on September 11, 2001, letters filled with a white powder containing deadly anthrax spores were sent to congressional offices and media companies. Five people died, 17 others became ill, and 10,000 more people were considered at risk of possible exposure to anthrax, in what is considered the worst biological attack in U.S. history.

New Anthrax Vaccine Approved

Anthrax continues to pose a significant public health concern due to its potential use as a bioterrorism agent and its ability to cause severe illness in humans. However, this summer a new anthrax vaccine was added to the U.S. arsenal of defense against bioterrorism. On July 20, 2023, the United States Food and Drug Administration (FDA) approved Cyfendus for use in adults aged 18 to 65 years exposed to anthrax.

Understanding Anthrax Causes and Symptoms

Anthrax is an infectious disease caused by the bacterium Bacillus anthracis. It can infect both humans and animals and is found all around the world.

Anthrax can be transmitted to humans via several routes of exposure to bacterial spores, including inhalation, intestinal absorption, injection, and skin wounds. It can be spread through direct or indirect contact with infected animals or contaminated animal products, or the intentional release of anthrax spores in the air.

Symptoms of anthrax depend on the type of infection but can include fever, chills, chest discomfort, coughing, shortness of breath, fatigue, vomiting, diarrhea, and skin lesions.

Inhalation anthrax is the deadliest form of the disease. Typical symptoms of inhalation anthrax develop within a week after exposure and include fever, chest pain, and shortness of breath.  Altered mental status, mediastinitis, and shock can then develop and typically lead to death if untreated.

Early recognition of anthrax symptoms is crucial for timely intervention.

Early Treatment Critical to Successful Management

The newly approved vaccine Cyfendus (Anthrax Vaccine Adsorbed, Adjuvanted) is indicated for people with suspected or confirmed inhalational exposure to anthrax. The vaccine is intended to be given in two intramuscular doses over two weeks, in combination with antibiotic prophylaxis, which often involves two months of treatment with ciprofloxacin, levofloxacin, or doxycycline.

Cyfendus has been in use under a pre-emergency use authorization status since 2019. Full FDA approval came after a manufacturer-conducted trial showing safety and an immune response protective against anthrax in healthy adults.

For post-exposure prophylaxis, Cyfendus provides more rapid protection than its predecessor, BioThrax. Approved by the FDA in 1972, BioThrax is administered in three doses over 28 days when used for post-exposure prophylaxis. Cyfendus uses an adjuvant to stimulate a rapid immune response against Bacillus anthracis in just two weeks.

Anthrax-specific medications may be given in addition to antibiotics: anthrasil, an immune globulin, and raxibacumab and obiltoxaximab, two monoclonal antibodies active against anthrax. Coordinate with your public health agencies to obtain these medications.

Prevention in Health Care Settings

Infection control measures are critical to prevent the spread of anthrax in health care settings. This includes the isolation of infected patients and strict adherence to standard and contact precautions. Routine vaccination against anthrax is recommended for health care personnel who may be at risk of occupational exposure.

While anthrax is relatively rare, health care personnel should be prepared to effectively manage and respond to cases of anthrax.