Prophylactic Treatment

Prophylactic treatment for persons exposed to anthrax spores

In the event of a known exposure to anthrax spores, antibiotic prophylaxis should be initiated as soon as possible - as described in the Table. Prophylaxis should continue until B. anthracis exposure has been excluded. For adults, children and pregnant women, ciprofloxacin is the drug of choice. Pharmokinetic studies have shown that ciprofloxacin achieves far higher concentrations in lung macrophages than penicillins, and is therefore a more effective prophylactic antibiotic. Ciprofloxacin has the added advantage that it is also an effective prophylactic treatment for other potential agents that may be used in deliberate release scenarios such as plague and tularemia. The risk of adverse effects from prophylaxis must be weighed against the risk of developing a serious disease.

After initial treatment with ciprofloxacin, doxycycline may be substituted to complete the 60 day prophylaxis. The duration of initial course of antibiotic treatment is currently 5 days. Only the initial course of antibiotics for prophylaxis is held in pods as part of the antibiotic stockpile. Arrangements for the supply of the remainder of the prophylactic course are being developed and individuals should be advised to report to their own GP. See DH Patient Group Directions for the initial and further supply of ciprofloxacin and the further supply of doxycycline in the event of exposure to a suspect biological agent.

In a major incident information on how to access stocks of antibiotics for the initial treatment or prophylaxis can be found on the DH website.

If B. anthracis exposure is confirmed, the organism must be tested for penicillin susceptibility. If susceptible, exposed persons may be treated with oral amoxicillin as an alternative to ciprofloxacin or doxycycline. The prophylaxis should continue for 60 days (recommended because of prolonged latency period that can elapse before germination of inhaled spores). During this period, no special precautions are required for exposed persons, but they should receive an anthrax information sheet and be instructed to seek medical attention immediately in the event of any suspicious symptoms.
 

Table: Recommended prophylaxis after exposure to B. anthracis

	Antimicrobial agent	Duration
Adults (including pregnant women)	Initial (5 day) therapy Ciprofloxacin 500mg orally every 12 hrs Further (55 day) therapy Ciprofloxacin 500mg orally every 12 hrs OR Doxycycline100mg orally every 12 hrs   Alternative therapy if strain is susceptible Amoxicillin 500mg orally three times daily	60 days
Children	Initial (5 day) therapy Ciprofloxacin 15mg/kg orally (maximum 500mg) every 12 hrs (not to exceed 1g per day)   Further (55 day) therapy Ciprofloxacin 15mg/kg orally (maximum 500mg) every 12 hrs (not to exceed 1g per day) Ciprofloxacin dose depends on age and weight, as a guide: newborn to 6months                100mg/day 1 year to less than 3 years      200mg/day 3 years to less than 5 years    300mg/day 5 years to less than 7 years    400mg/day 7 years to less than 12 years  500mg/day 12+ years (adult dose)           1000mg/day   OR Doxycycline 100mg every 12hrs (NB: only for children less than 8 years old and under 45kg Alternative therapy if strain is susceptible Amoxicillin 80mg/kg per day, in three doses (not to exceed 500mg/dose)	60 days

 

Immunisation for exposed persons

In certain circumstances, in addition to antimicrobial prophylaxis, post-exposure immunisation may also be indicated. This consists of three doses of vaccine at 0, 3 and 6 weeks after exposure (with added doses at 6 months and 1 year if there is continued exposure). With vaccination, post-exposure antibiotic prophylaxis can be reduced to 4 weeks. Prompt post-exposure prophylaxis with antibiotics and vaccine appears to be highly effective.

Note that anthrax vaccination is currently only available for people with an occupational risk of exposure. This includes people who work with animal hides or products and laboratory staff who handle the organism routinely. Prophylactic anthrax vaccination is not required for other members of the public. In the event of a deliberate release, individuals will be considered for vaccination on a case-by-case basis, according to their risk of exposure.

Contacts of cases

There is no need to provide antibiotic prophylaxis or immunisation to contacts of patients unless there is concern that they were also exposed to the initial release.

Prophylactic treatment for frontline and healthcare workers

Frontline workers entering the exposed zone should be offered antibiotic prophylaxis as in the Table, and in addition, should be offered a course of vaccination at 0, 3 and 6 weeks following exposure (with added doses at 6 months and 1 year if there is continued exposure) subject to availability .

Prophylactic treatment may also be considered for frontline workers involved in other activities including:

• Decontamination of exposed persons
• Handling exposed persons
• Management of patients or disposal of bodies infected with anthrax.

Decisions about who should receive prophylaxis should be taken on an individual basis according to duration and degree of potential exposure, and taking into account the availability and side effects of prophylactic treatments.

Prevention of secondary spread

Person-to-person spread of anthrax is negligible, and therefore there is no specific treatment or advice required for secondary contacts. There is no requirement for quarantine of infected patients. However, those contaminated with anthrax spores will need to be decontaminated. There is no need to provide antibiotic prophylaxis or immunisation to contacts of patients unless there is concern that they were also exposed to the initial release.

Last reviewed: 23 December 2010