Clinical Review
Prophylaxis
Is a vaccine on the way?
Development of an Ebola vaccine is under way. The most promising vaccine to date is cAd3-ZEBOV (GlaxoSmithKline, Brentford, London, United Kingdom). This vaccine is derived from a chimpanzee adenovirus, called Chimp Adenovirus type 3 (ChAd3), which has been genetically engineered to express proteins from both the Zaire and Sudan species of Ebola virus to provoke an immune response against them. Phase 1 trials of this vaccine began in September 2014.17
Appropriate precautions
Until an effective vaccine is available, a number of recommendations have been put in place in an effort to prevent Ebola infection:
- Avoid all nonessential travel to West Africa, especially to Sierre Leone, Guinea, and Liberia.7
- Avoid exposure to bodily fluids of patients who have been exposed to or are at high risk of having Ebola. This includes individuals who are febrile or feeling unwell and who have traveled to West Africa within the previous 21 days, especially if they visited 1 of the 3 countries with the highest Ebola infection rates (Sierre Leone, Guinea, and Liberia).
- Introduce universal screening of all patients, family members, and employees entering labor and delivery units.
Classifying risk and risk-associated protocols
If an at-risk patient is identified, she should be placed in isolation and consultation with an infectious disease specialist should occur. Using appropriate personal protective equipment (PPE), a detailed history and physical examination should be performed, and the patient should be classified according to risk14,15:
- No risk—defined as those who traveled to an Ebola-affected country more than 21 days previously, those in contact with an asymptomatic person prior to them being diagnosed with Ebola, and those in contact with an asymptomatic person who in turn had contact with an infected individual.
- Low risk—including those who traveled to an Ebola-affected country within 21 days but are asymptomatic, those with brief contact with asymptomatic infected individuals, those exposed to infected individuals in countries without widespread disease while wearing PPE, and those in brief proximity to a symptomatic individual, such as being in the same room or on the same airplane.
- Some (moderate) risk—including those in close contact (within 1 m) with a symptomatic individual or those exposed to an infected individual in a country with widespread disease while wearing PPE.
- High risk—defined as those exposed to the bodily fluids of an infected individual without PPE.
When should a patient be tested for Ebola, and what does that testing entail?
Patients found to be at no risk should not be tested or monitored, regardless of whether or not they are symptomatic. Asymptomatic patients with risk factors should not be tested for the Ebola virus. However, they do need to be followed for signs and symptoms of infection. At this time, the CDC has decided that it will take on the responsibility of monitoring all such patients until they are out of the 21-day window.14,15
Symptomatic patients with risk factors should be tested for the Ebola virus, regardless of whether they are designated as being at low, moderate, or high risk of infection. Strict infection control precautions should be followed for such patients, and local/state health departments should be notified. Laboratory testing includes RT-PCR or Ebola immunoassay. A negative RT-PCR test result obtained more than 72 hours after the onset of symptoms effectively rules out Ebola infection. In general, patients can be discharged from the hospital if they are asymptomatic and have 2 negative RT-PCR test results within 48 hours.14,15
Other diagnoses that should be considered in these patients include influenza, malaria, Lassa fever, meningococcal infection, and typhoid. If a patient is asymptomatic but at risk, all nonemergent medical care should be deferred until they are out of the 21-day window. Repeat testing may be warranted in certain clinical scenarios.
Management of infected patients in a maternity ward
While no pregnant patient has yet been diagnosed with Ebola infection in the United States, it remains a possibility, and clinicians should be aware of appropriate management actions. Once the diagnosis is confirmed, patients and their families should be placed in strict isolation. In some states, specific regional centers have been designated to care for these patients. They should be cared for by a small, dedicated team of clinicians dressed in state-of-the-art PPE and fully trained in the technique of donning and doffing the gear. Some institutions have mandated that no medical students or residents be involved directly in the care of these patients. Infectious disease specialists should be actively involved. All medical equipment (such as stethoscopes, blood pressure cuffs, thermometers, and fetal heart rate monitors) should be dedicated to the care of this patient alone and should remain in the room, as the virus can remain viable on surfaces for “a few hours or days.”18
